SynC · SynC Standards

Building Thermal Insulation

Rev5
IssuedJun 12, 2026

Revision history

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1 Scope

NOTE This standard governs the selection, specification, and installation of thermal insulation in the building envelope for buildings constructed under the International Building Code (IBC), International Energy Conservation Code (IECC), or ASHRAE 90.1 energy standard. (1.1)
NOTE It applies to new construction and to alterations that affect the thermal performance of existing assemblies. (1.2)
NOTE The standard addresses the full range of insulation materials used in commercial and residential building envelope assemblies, the verification of thermal performance, fire and smoke classification, moisture management through vapor retarder and air barrier coordination, installation quality grading, and the inspection and testing required to confirm that specified performance is actually achieved in the field. (1.3)
NOTE Thermal insulation is one of the most cost-effective energy conservation measures in a building, and its in-place thermal performance depends not only on the material's rated R-value but on how it is installed — whether cavities are completely and uniformly filled, whether thermal bridges are properly broken, whether vapor control is correctly placed, and whether the assembly remains dry over its service life. (1.4)
NOTE A well-specified insulation scope that is poorly installed may achieve only 50 to 70 percent of its design R-value, which is why this standard addresses both material requirements and installation requirements with equal rigor. (1.5)
NOTE The building envelope is also the primary line of defense against moisture accumulation within the building structure, and incorrect placement of vapor retarders, mismatched permeance between assembly layers, and gaps in the air barrier all create conditions for condensation and long-term moisture damage. (1.6)
1.7 Insulation specification shall be coordinated with the vapor retarder requirements of IBC Section 1405 and the air barrier requirements of IECC Section C402.5 and ASHRAE 90.1 Section 5.4.
1.8 Roof assemblies where insulation is specified as part of a single-ply, modified bitumen, or built-up roofing scope shall be coordinated with Membrane Roofing.
1.9 Insulation installed on the exterior of below-grade foundation walls as protection board over waterproofing shall be coordinated with Below Grade Waterproofing.
1.10 Details at the interior face of insulated wall assemblies shall be coordinated with Gypsum Board Assemblies.
1.11 Duct insulation within the building envelope shall be coordinated with Hvac Ductwork.
1.12 Where a separate fluid-applied air barrier membrane is used in conjunction with continuous insulation sheathing, the work shall be coordinated with Air Barriers.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of the following standards and codes.
Standard Title
ASHRAE 90.1 Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings
ICC IECC International Energy Conservation Code
IBC Chapter 7 Fire and Smoke Protection Features
IBC Chapter 14 Exterior Walls (vapor retarder requirements)
IBC Section 2603 Foam Plastic Insulation
ASTM C165 Standard Test Method for Measuring Compressive Properties of Thermal Insulations
ASTM C177 Standard Test Method for Steady-State Heat Flux and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
ASTM C518 Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
ASTM C553 Standard Specification for Mineral Fiber Blanket Thermal Insulation for Commercial and Industrial Applications
ASTM C578 Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation
ASTM C612 Standard Specification for Mineral Fiber Block and Board Thermal Insulation
ASTM C665 Standard Specification for Mineral-Fiber Blanket Thermal Insulation for Light Frame Construction and Manufactured Housing
ASTM C1029 Standard Specification for Spray-Applied Rigid Cellular Polyurethane Thermal Insulation
ASTM C1289 Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board
ASTM C1320 Standard Practice for Installation of Mineral Fiber Batt and Blanket Thermal Insulation for Light Frame Construction
ASTM C1338 Standard Test Method for Determining Fungi Resistance of Insulation Materials and Facings
ASTM E84 Standard Test Method for Surface Burning Characteristics of Building Materials
ASTM E96 Standard Test Methods for Water Vapor Transmission of Materials
ASTM E283 Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors
RESNET HERS Residential Energy Services Network Home Energy Rating System Standards (for installation grading)
NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components
ICC 1100 Standard for Spray-Applied Polyurethane Foam Plastic Insulation
2.2 Where the contract documents, the adopted building code, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record or Architect of Record directs otherwise in writing.

3 Submittals

3.1 Action Submittals

3.1.1 Contractor shall submit the following for the Architect's or Engineer's review prior to procurement and installation:
  • Product data for each insulation type, including material composition, physical properties (density, R-value at stated thickness and mean temperature), facing description, and dimensional tolerances, demonstrating conformance with the applicable ASTM product standard
  • Third-party thermal resistance test reports per ASTM C518 or C177 for each insulation product, confirming the stated R-value per inch (RSI per 25mm) at the design mean temperature
  • ASTM E84 flame spread and smoke developed test reports for all insulation products that will be exposed or require classification documentation
  • For foam plastic insulation: documentation that the product has been tested in the intended wall or roof assembly per NFPA 285 where required by IBC Section 2603.5, unless an exemption under IBC Section 2603.5 applies
  • Vapor retarder product data including permeance rating per ASTM E96 and temperature/humidity range of applicability
  • For spray-applied polyurethane foam: contractor qualifications, installer certifications, proposed mix ratio and density range, substrate preparation requirements, and Safety Data Sheets
  • Sample of each insulation product where required for color, finish, or facing verification
  • Manufacturer's installation instructions for each insulation type, including minimum substrate temperature requirements, coverage rates for spray-applied products, and fastener or adhesive recommendations for board products
Action Submittals Requiredcheckbox
Product data and physical properties for each insulation type
ASTM C518 or C177 thermal resistance test reports
ASTM E84 surface burning test reports
NFPA 285 assembly fire test documentation (foam plastic in exterior walls)
Vapor retarder product data and permeance rating
Spray-applied polyurethane foam installer qualifications and mix documentation
Manufacturer installation instructions for each insulation type
3.1.2 The Contractor shall submit the action submittals listed for this standard for the Architect's or Engineer's review prior to procurement and installation.
3.1.3 Installation of insulation in any assembly shall not proceed until the corresponding submittals are reviewed and returned without rejection.

3.2 Closeout Submittals

3.2.1 Contractor shall provide the following at substantial completion prior to final acceptance:
  • Certificate of compliance signed by the Contractor certifying that all insulation was installed in full conformance with the approved submittals, the manufacturer's instructions, and this standard
  • Inspection records and field test reports, including blower door or tracer gas air barrier test results where required
  • Copies of any third-party inspection or HERS rater reports where energy code compliance documentation requires a field grading inspection
  • Warranty documentation for products carrying a manufacturer warranty
Closeout Submittals Requiredcheckbox
Contractor certificate of compliance (signed)
Inspection records and field test reports (including air barrier test results where required)
Third-party inspection or HERS rater reports (where required for energy code compliance)
Warranty documentation for products carrying a manufacturer warranty
3.2.2 The Contractor shall provide the closeout submittals listed for this standard at substantial completion prior to final acceptance.

4 Quality Assurance

4.1 Installer Qualifications

4.1.1 A certified SPF applicator shall be on-site during all SPF application operations, and SPF shall not be applied by untrained laborers.
Minimum Installation Grade Required (RESNET)radio
Grade I — uniform fill, no voids, splits around obstructions
Grade II — minor compression or gaps permitted per RESNET limits
Grade III — not acceptable for conditioned assemblies
4.1.2 Insulation work shall be performed by installers experienced in the installation of the specific insulation type and assembly being executed.
4.1.3 Spray-applied polyurethane foam (SPF) installation shall be performed by an applicator trained and certified by the foam system manufacturer, or by an applicator holding certification under a recognized SPF training program.
4.1.4 Mineral fiber batt and blanket installation in assemblies subject to HERS rating or energy code documentation shall achieve RESNET Grade I installation in all conditioned-space assemblies unless the project energy model explicitly accounts for a lower installation grade in the HERS score or compliance calculation.
4.1.5 Installation grade shall be verified by a HERS rater or a qualified third-party inspector before assemblies are closed.

4.2 Regulatory and Energy Code Compliance

4.2.1 Insulation shall be specified and installed to meet the minimum requirements of the energy code adopted by the Authority Having Jurisdiction.
4.2.2 The Contractor shall treat the insulation scope as a regulated energy-code element, not merely a material supply item.
4.2.3 Where the project uses a prescriptive compliance path under IECC or ASHRAE 90.1, minimum R-values by climate zone shall be met for each assembly type.
4.2.4 Where the project uses a performance compliance path (energy modeling), the modeled assembly R-values shall be achievable with the specified materials and installation method.
4.2.5 The Contractor shall verify that no assembly is closed — drywalled over, covered by cladding, or membraned — before the insulation in that assembly has been inspected by the Authority Having Jurisdiction, the HERS rater, or the designated third-party inspector as required by the adopted energy code.

4.3 Listing, Labeling, and Product Certification

Polyisocyanurate R-Value Basisradio
LTTR (Long-Term Thermal Resistance per ASTM C1289) — required for energy code compliance
Initial (aged 180 days) — confirm acceptability with AHJ before use
4.3.1 All insulation products shall be listed, labeled, and certified by the manufacturer as conforming to the applicable ASTM product standard.
4.3.2 Labels shall be intact on delivered materials.
4.3.3 The stated R-value on the label or product data sheet shall be based on tests conducted per ASTM C518 or C177 at the mean temperature relevant to the application (75°F mean temperature for most building envelope applications).
4.3.4 Polyisocyanurate board insulation shall be labeled with its Long-Term Thermal Resistance (LTTR) value per ASTM C1289, not its initial thermal resistance.
NOTE Polyiso's thermal performance decreases over the first several years after manufacture as blowing agent gases diffuse out of the foam cells; LTTR represents the stabilized in-service value and is the appropriate basis for energy code compliance calculations. (4.3.5)

5 Thermal Performance and Energy Code Basis

5.1 Climate Zone and Prescriptive Requirements

NOTE The minimum R-values required by the adopted energy code (IECC or ASHRAE 90.1) are a function of climate zone, building type (residential or commercial), and assembly type (roof/ceiling, above-grade wall, below-grade wall, slab). (5.1.1)
Project Climate Zone (IECC/ASHRAE)select
Zone 1 (Tropical — Miami, Honolulu)
Zone 2 (Hot/Humid — Houston, Phoenix)
Zone 3 (Warm — Atlanta, Los Angeles)
Zone 4 (Mixed — Baltimore, Seattle)
Zone 4 Marine (Pacific Northwest)
Zone 5 (Cool — Chicago, Denver)
Zone 6 (Cold — Minneapolis, Burlington)
Zone 7 (Very Cold — Duluth, Fairbanks)
Zone 8 (Sub-Arctic — Anchorage interior)
Per drawings
Energy Code Compliance Pathradio
Prescriptive (minimum R-values from IECC Table R402.1.2 or ASHRAE 90.1 Table 5.5)
Trade-off (UA trade-off or component performance approach)
Performance (whole-building energy model)
5.1.2 The Contractor shall obtain the climate zone for the project location from the drawings or from the energy code report; the climate zone governs minimum R-values throughout this standard.
5.1.3 The prescriptive minimum R-values for the project climate zone shall be as tabulated on the energy compliance drawings or energy code compliance report.
5.1.4 These values represent the minimum acceptable performance level; the Architect or Engineer may specify higher R-values for energy efficiency, owner goals, or resilience objectives.

5.2 Assembly R-Value vs. Nominal R-Value

NOTE The nominal R-value of an insulation product is the R-value of the insulation material alone. (5.2.1)
NOTE The assembly R-value is the thermal performance of the complete wall, roof, or floor section including framing members, air films, and all other materials. (5.2.2)
NOTE These are not the same. (5.2.3)
Wall Assembly Thermal Performance Basisradio
Nominal cavity R-value (not compliant with ASHRAE 90.1 prescriptive tables)
Whole-wall effective R-value per ASHRAE 90.1 Appendix A (required for prescriptive compliance)
As modeled in energy compliance simulation (performance path)
NOTE Framing members in stud walls and roof framing create thermal bridges that substantially reduce the assembly R-value below the cavity R-value, and ASHRAE 90.1 Section 5.5 and the supporting tables are based on assembly R-values (opaque assemblies), not nominal cavity R-values. (5.2.4)
NOTE For a typical wood-framed wall with 2×6 studs at 16 inches on center, the framing fraction reduces the effective clear-field R-19 cavity assembly to approximately R-15 to R-17 at the whole-wall level, which is why IECC and ASHRAE 90.1 increasingly require continuous insulation layers on the exterior of framed walls to supplement the cavity insulation and reduce the influence of framing members on whole-assembly performance. (5.2.5)

5.3 Design R-Values by Assembly

NOTE The following datasheet elements record the specified minimum R-values for submittal verification and field inspection documentation. (5.3.1)
Roof/Ceiling Assembly — Specified R-Valuerange
R (h·ft²·°F/Btu)
2090
2025303849607590
Default: 49 R (h·ft²·°F/Btu)
Per drawings
Above-Grade Wall Assembly — Specified R-Value (cavity + continuous)range
R (h·ft²·°F/Btu)
1340
13152025303540
Default: 20 R (h·ft²·°F/Btu)
Per drawings
Continuous Insulation Component — Above-Grade Wallrange
R (h·ft²·°F/Btu)
025
57.51012152025
Default: 5 R (h·ft²·°F/Btu)
Per drawings
Below-Grade Wall Assembly — Specified R-Valuerange
R (h·ft²·°F/Btu)
020
57.5101520
Default: 10 R (h·ft²·°F/Btu)
Per drawings
Floor/Ceiling over Unconditioned Space — Specified R-Valuerange
R (h·ft²·°F/Btu)
1338
1319253038
Default: 19 R (h·ft²·°F/Btu)
Per drawings
Slab-Edge / Foundation Perimeter — Specified R-Valuerange
R (h·ft²·°F/Btu)
020
5101520
Default: 10 R (h·ft²·°F/Btu)
Per drawings

6 Insulation Materials

6.1 General Material Requirements

6.1.1 All insulation materials shall be new, undamaged, and free of moisture at time of installation.
6.1.2 Materials that have been wetted, compressed, torn, or otherwise damaged in storage or handling shall be discarded and replaced.
6.1.3 The Contractor shall store insulation materials in a dry, covered location, off the ground, and protected from exposure to weather, mechanical damage, and UV degradation until immediately before installation.

6.2 Mineral Fiber Batt and Blanket Insulation

NOTE Mineral fiber includes glass fiber (fiberglass) and mineral wool (rock or slag wool) products. (6.2.1)
Mineral Fiber Batt/Blanket Product Typeradio
Glass fiber (fiberglass) batt — ASTM C665 (light frame)
Glass fiber blanket — ASTM C553 (commercial/industrial)
Mineral wool (rock or slag wool) board — ASTM C612
Not used in this project
Mineral Fiber Batt/Blanket — Nominal R-Value per Inchselect
R-3.2 per inch (standard glass fiber)
R-3.7 per inch (high-density glass fiber)
R-4.0 per inch (mineral wool)
Mineral Fiber Batt/Blanket — Facingradio
Unfaced (no vapor retarder facing)
Kraft-faced (Class II vapor retarder, 0.1–1.0 perm)
Foil-faced (Class I vapor retarder, ≤0.1 perm)
Friction-fit (unfaced, friction-fit in cavity)
6.2.2 Mineral fiber batt and blanket insulation for light frame construction shall conform to ASTM C665.
6.2.3 Mineral fiber blanket for commercial and industrial applications shall conform to ASTM C553.
6.2.4 Mineral wool (rock wool or slag wool) board insulation shall conform to ASTM C612.
NOTE Mineral fiber is noncombustible per ASTM E136 and requires no thermal or ignition barrier when installed in noncombustible assemblies or when left exposed in unconditioned spaces such as attics, and its noncombustibility is one of its key advantages in fire-sensitive applications. (6.2.5)
NOTE Mineral wool board products offer higher compressive strength, greater dimensional stability at elevated temperature, and better moisture resistance compared to glass fiber batts, making them well-suited for continuous exterior insulation and under-slab applications. (6.2.6)
6.2.7 The kraft facing shall face the conditioned space side of the assembly in heating-dominated climates (zones 5–8).
6.2.9 Where facing material is also intended to serve as the vapor retarder, the specifier shall confirm that the facing's permeance is appropriate for the climate zone and assembly configuration.

6.3 Rigid Extruded Polystyrene (XPS) Insulation

NOTE XPS is produced by extruding molten polystyrene through a die, yielding a closed-cell foam with low water vapor permeance (typically 1.0 perm at 1-inch thickness), high compressive strength, and good moisture resistance. (6.3.1)
NOTE XPS delivers approximately R-5.0 per inch, and unlike polyiso its R-value per inch is relatively stable across a wide temperature range, which is an advantage in cold-climate below-grade and at-grade applications. (6.3.2)
XPS Board — ASTM C578 Compressive Resistance Typeselect
Type XIII — 10 psi (under-slab, lightly loaded)
Type II — 15 psi (general below-grade and above-grade CI)
Type IV — 25 psi (moderate load, parking deck)
Type VII — 40 psi (heavy load, plaza deck)
Type V — 60 psi (heavy vehicular, cold storage)
Not used
XPS Board Nominal Thicknessrange
inches
0.54
0.511.522.534
Default: 2 inches
Per drawings
6.3.3 Extruded polystyrene rigid board insulation shall conform to ASTM C578.
6.3.4 ASTM C578 classifies XPS into multiple types by compressive strength; the appropriate type shall be selected based on the structural loads to which the insulation will be subjected.
6.3.5 The blowing agents used historically in XPS production had high global warming potential; many manufacturers have transitioned to lower-GWP blowing agents, and the specifier should confirm the product's blowing agent status where environmental criteria apply.

6.4 Rigid Expanded Polystyrene (EPS) Insulation

NOTE EPS is produced by expanding polystyrene beads in a mold; it has an open-cell micro-texture that allows water vapor to pass more freely than XPS, with permeance typically 2–5 perms at 1-inch thickness depending on density. (6.4.1)
NOTE EPS delivers approximately R-3.6 to R-4.2 per inch depending on density; higher-density EPS achieves higher R-value per inch and higher compressive strength. (6.4.2)
EPS Board — Density and Compressive Strengthselect
Type I — 0.90 pcf, 10 psi
Type II — 1.25 pcf, 15 psi (general-purpose)
Type IX — 1.50 pcf, 25 psi
Type XIV — 1.80 pcf, 40 psi (high load)
Not used
6.4.3 Expanded polystyrene rigid board insulation shall conform to ASTM C578 (EPS types).
NOTE EPS is dimensionally stable and does not shrink or expand significantly over time, making it well-suited for below-grade applications where long-term dimensional stability is important; it does not use blowing agents with significant global warming potential and retains most of its R-value over time, unlike polyiso at low temperatures. (6.4.4)
NOTE EPS is appropriate for below-grade walls, under-slab insulation, and as continuous exterior sheathing where its higher vapor permeance is acceptable or desirable for the assembly's moisture management strategy. (6.4.5)

6.5 Polyisocyanurate Board (Polyiso) Insulation

NOTE Polyiso delivers the highest R-value per inch of any commercially available rigid board insulation under standard test conditions (approximately R-6.5 per inch at 75°F mean temperature), making it the dominant insulation choice for low-slope commercial roofing and exterior continuous insulation in above-grade walls. (6.5.1)
Polyisocyanurate Board — ASTM C1289 Type (Facing)select
Type I (glass fiber-reinforced felt facers, both sides)
Type II (glass fiber-reinforced felt or coated glass mat, one or both sides)
Foil-faced (aluminum foil facer, both sides)
Not used
Polyisocyanurate Board — Specified LTTR R-Valuerange
R (h·ft²·°F/Btu)
6.540
6.5131619.525303540
Default: 25 R (h·ft²·°F/Btu)
Per drawings
Polyisocyanurate Board Nominal Thicknessrange
inches
16
11.522.533.544.556
Default: 4 inches
Per drawings
6.5.2 Polyisocyanurate board insulation shall conform to ASTM C1289.
NOTE A critical characteristic of polyiso is its temperature-dependent thermal resistance: at mean temperatures below approximately 40°F, polyiso's R-value degrades substantially — by 20 to 35 percent depending on product and temperature — and this degradation is reversible but means that polyiso specified solely on its 75°F test value may not deliver the expected winter performance in cold-climate continuous insulation applications. (6.5.3)
6.5.4 For climate zones 5–8, the specifier should either use LTTR values, account for thermal performance at cold conditions, or supplement polyiso with a layer of XPS or mineral wool that maintains performance at low temperatures.
NOTE ASTM C1289 classifies polyiso into types based on facing material; the most common facing for roofing applications is a glass fiber-reinforced felt or glass mat facer (Type I, Type II), while for wall applications foil-faced polyiso is commonly used and provides a Class I vapor retarder and radiant barrier, and the facing determines the product's vapor permeance, fire performance classification, and suitability for specific adhesives and field cuts. (6.5.5)

6.6 Spray-Applied Polyurethane Foam (SPF)

NOTE SPF is applied as a two-component liquid system that expands and cures in place, filling complex geometries, bridging gaps, and adhering to the substrate. (6.6.1)
NOTE It is the only insulation type that simultaneously provides insulation and a continuous air barrier in a single material application, which is a significant installation advantage in complex assemblies with many penetrations and irregular framing. (6.6.2)
NOTE Closed-cell SPF delivers approximately R-6.0 to R-7.0 per inch, has very low vapor permeance (less than 1.0 perm at 2 inches), high structural rigidity, and excellent moisture resistance; open-cell SPF delivers approximately R-3.5 to R-3.8 per inch, has higher vapor permeance (greater than 10 perms), lower density, and lower cost per R-unit. (6.6.3)
SPF Typeradio
Closed-cell SPF (ccSPF) — ASTM C1029, approximately R-6.5/inch, Class II vapor retarder at 2 in.
Open-cell SPF (ocSPF) — ICC 1100, approximately R-3.7/inch, high vapor permeance (>10 perm)
Not used
SPF Minimum Applied Thicknessrange
inches
17
11.522.533.5455.567
Default: 3.5 inches
Per drawings
SPF Minimum Applied Densityradio
Closed-cell: 1.7–2.2 pcf (per ASTM C1029 Type II)
Closed-cell: 2.5–3.0 pcf (per ASTM C1029 Type III, higher compressive strength)
Open-cell: 0.4–0.5 pcf (per ICC 1100)
SPF Thickness Verification Methodradio
Probe and measure during application by installer
Third-party core sampling after installation
Both probe-during-application and third-party core sampling
6.6.4 Spray-applied polyurethane foam insulation shall conform to ASTM C1029 for closed-cell SPF (ccSPF) and to ICC 1100 for open-cell SPF (ocSPF).
6.6.5 Closed-cell SPF applied at 2 inches meets the vapor retarder requirement of many climate zones as a Class II retarder.
6.6.6 Open-cell SPF is not an adequate vapor retarder and is not moisture-resistant, and shall not be used in roofing applications, on exterior surfaces exposed to weather, or in any location where its high vapor permeance would create a vapor or moisture management problem.
6.6.7 The SPF manufacturer's minimum substrate temperature (typically 40°F) shall be met and maintained during application and cure.
6.6.8 Application outside the manufacturer's environmental window shall not proceed and shall require written authorization from the SPF manufacturer.
6.6.9 SPF cores shall be taken in locations agreed upon with the Architect during the pre-application meeting, at a frequency of at least one core per 1,000 square feet of applied area, or as directed by the contract documents.
6.6.10 Core locations shall be patched by the SPF installer immediately after sampling with the same SPF material.

7 Fire and Smoke Characteristics

7.1 General Fire Requirements

7.1.1 All insulation materials installed in building envelope assemblies shall meet the fire and smoke classification required by the IBC for the specific assembly and occupancy.
7.1.2 The Contractor shall confirm the applicable fire code requirement for each assembly before procurement and shall not substitute insulation products that alter the fire classification of a tested assembly.

7.2 ASTM E84 Classification

NOTE ASTM E84 (Steiner Tunnel test) measures the Flame Spread Index (FSI) and the Smoke Developed Index (SDI) of the material surface. (7.2.1)
NOTE IBC Chapter 8 and Chapter 26 use these indices to classify interior finish and foam plastic insulation. (7.2.2)
NOTE The standard reporting convention is "FSI/SDI" (e.g., 25/450). (7.2.3)
Required ASTM E84 Classification — Flame Spread Index (FSI)radio
Class A — FSI 0–25 (IBC Type I/II/III/IV occupancies, most exposed applications)
Class B — FSI 26–75 (limited exposed applications per IBC)
Class C — FSI 76–200 (concealed within assemblies only)
Not required (noncombustible mineral fiber in noncombustible assembly)
Required ASTM E84 Smoke Developed Index (SDI) Maximumradio
450 or less (IBC standard requirement for foam plastic insulation per Section 2603)
Specific lower value required — see drawings/energy code report
Not required (noncombustible mineral fiber)
7.2.4 Insulation materials required to demonstrate surface burning characteristics shall be tested per ASTM E84 (Steiner Tunnel test).
NOTE Mineral fiber (glass fiber and mineral wool) insulation products are noncombustible and are not subject to the ASTM E84 requirements imposed on foam plastic insulation; however, mineral fiber products with facings (kraft, foil, or composite) do require surface burning classification of the faced assembly if the facing is left exposed, and unfaced mineral fiber in a concealed cavity does not require ASTM E84 documentation. (7.2.5)

7.3 Foam Plastic Insulation — IBC Section 2603 Requirements

NOTE Foam plastic insulation installed in buildings regulated by the IBC is subject to IBC Section 2603. (7.3.1)
NFPA 285 Assembly Test Documentationradio
Required — assembly test report on file, confirmed matching assembly conditions
Exempt — exterior wall is Type I/II noncombustible construction without combustible components
Exempt — foam is installed in concrete or masonry wall fully protected per IBC 2603.5.6
Not applicable — no foam plastic in exterior walls
Foam Plastic — Ignition Barrier in Attic/Crawl Spaceradio
Required — 1-1/2 in. mineral fiber over foam per IBC 2603.9
Required — 3/8 in. gypsum wallboard over foam per IBC 2603.9
Required — 1/4 in. wood structural panel over foam per IBC 2603.9
Not required — foam product listed as ignition-barrier-exempt per IBC 2603.9 exception
Not applicable — no foam in attic or crawl space
7.3.2 IBC Section 2603.3 requires that foam plastic insulation have a maximum FSI of 75 and maximum SDI of 450 per ASTM E84 in all applications except where the insulation is installed within a tested assembly.
7.3.3 IBC Section 2603.4 requires that foam plastic insulation be separated from all interior spaces by a thermal barrier of minimum 15-minute fire resistance, unless an exception in Section 2603.4.1 applies, the standard thermal barrier being 1/2-inch gypsum board.
NOTE Exceptions to the thermal barrier include foam plastic within roofing systems, within HVAC plenums that are entirely enclosed by noncombustible materials, and specific listed assemblies. (7.3.4)
7.3.5 IBC Section 2603.5 requires that exterior walls containing foam plastic insulation meet the fire propagation requirements of NFPA 285, which is a full-scale assembly fire test evaluating whether fire propagates vertically through the exterior wall assembly, including the foam insulation, any combustible drainage plane materials, and the exterior cladding.
7.3.6 NFPA 285 shall be satisfied for the entire assembly, not just the individual foam product, and a product's ASTM E84 classification does not substitute for NFPA 285 assembly testing where NFPA 285 is required.
7.3.7 The Contractor shall confirm that any exterior wall assembly containing foam plastic has a documented NFPA 285 test or qualifies for an exemption before procurement.
7.3.8 IBC Section 2603.9 (attics and crawl spaces) requires that foam plastic insulation within an attic or crawl space entered only for utility service be protected from ignition by a covering of 1-1/2-inch mineral fiber insulation, 1/4-inch wood structural panel or equivalent, 3/8-inch gypsum wallboard, or another approved ignition barrier material, unless the foam product has been specifically tested and listed as an ignition-barrier-exempt material.

8 Vapor Retarders and Air Barrier Coordination

8.1 Vapor Retarder Classification

8.1.1 Vapor retarders shall be classified by water vapor permeance as determined by ASTM E96 wet-cup or dry-cup method.
Vapor Retarder Class — Above-Grade Wallradio
Class I (≤0.1 perm) — foil or polyethylene sheet
Class II (0.1–1.0 perm) — kraft facer or coated membrane
Class III (1.0–10 perm) — latex paint on gypsum board
None required (Climate Zones 1–3 and per IBC 1405.3 exceptions)
Vapor Retarder Location in Wall Assemblyradio
Interior side of insulation (warm-in-winter face) — heating-dominated climates
Exterior side of insulation — cooling-dominated climates only (confirm with architect)
Integral facer on cavity insulation
No vapor retarder in assembly
8.1.2 Class I vapor retarders have permeance of 0.1 perm or less (examples: polyethylene sheet, aluminum foil, foil-faced polyiso facer) and shall be used only where specified by the Architect, because they are highly restrictive and can trap moisture in assemblies that experience seasonal reversal of vapor drive.
NOTE Class II vapor retarders have permeance greater than 0.1 perm and at or below 1.0 perm (examples: kraft-faced insulation facer, coated kraft paper, some low-permeance paints) and are appropriate in cold-climate above-grade walls where vapor drive from inside to outside is dominant in winter. (8.1.3)
NOTE Class III vapor retarders have permeance greater than 1.0 perm and at or below 10 perms (examples: standard latex paint on gypsum board, house wrap materials in this range) and are appropriate only in climate zones where adequate continuous insulation on the exterior prevents condensation within the wall cavity (per IBC Table 1405.3.3 ratios), shifting the dew point to the exterior side of the thermal envelope. (8.1.4)

8.2 Climate Zone Guidance for Vapor Retarder Selection

NOTE IBC Section 1405.3 and IRC Section R702.7 establish the climate-zone vapor retarder requirements set out below. (8.2.1)
Continuous Exterior Insulation R-Value / Total Wall R-Value Ratio — IBC 1405.3.3 Complianceradio
Ratio verified — exterior CI is sufficient to allow Class III vapor retarder per IBC Table 1405.3.3
Ratio not met — Class I or II vapor retarder required on interior face
Climate Zones 1–3 — no vapor retarder required
8.2.2 Climate Zones 5, 6, 7, 8, and Marine 4 require a Class I or II vapor retarder on the interior (warm-in-winter) face of the frame wall insulation, unless the assembly includes sufficient continuous exterior insulation to keep the interior wall sheathing above the dew point.
NOTE Climate Zones 1, 2, and 3 do not require a vapor retarder, and in hot-humid climates a vapor retarder on the interior face is actually counterproductive because it traps moisture driven inward by outdoor humidity. (8.2.3)
8.2.4 Climate Zone 4 (non-marine) requires a Class I, II, or III vapor retarder.
NOTE The minimum ratio of exterior continuous insulation R-value to total wall R-value required to shift the dew point and allow a Class III vapor retarder (painted drywall) in lieu of Class I or II is established in IBC Table 1405.3.3 and varies by climate zone and wall R-value. (8.2.5)
8.2.6 The Contractor shall not substitute vapor retarder products without confirming compliance with the applicable IBC table and climate zone requirements.

8.3 Coordination with Air Barrier

NOTE The air barrier and the vapor retarder serve different functions and are not always the same material: the air barrier resists bulk air movement through the assembly, while the vapor retarder controls diffusion of water vapor through the material. (8.3.1)
8.3.2 The air barrier should be continuous across the entire building envelope; the vapor retarder is placed at a specific layer within the assembly.
NOTE In SPF assemblies, closed-cell SPF serves simultaneously as insulation, vapor retarder, and air barrier in the locations where it is applied; in assemblies using batt cavity insulation with a separate house wrap air barrier on the exterior sheathing, the air barrier and vapor retarder are distinct layers. (8.3.3)
Air Barrier System Coordinationradio
SPF serves as combined insulation, vapor retarder, and air barrier
Separate house wrap or fluid-applied air barrier
Interior vapor barrier (polyethylene sheet) sealed to framing as air barrier and vapor retarder
Continuous rigid board insulation with taped joints as air barrier layer
8.3.4 The Contractor shall confirm that no gap, penetration, or construction joint interrupts the continuity of either the air barrier layer or the vapor retarder layer.
8.3.5 Penetrations through the vapor retarder — for electrical boxes, pipes, and mechanical connections — shall be sealed with compatible materials per the vapor retarder manufacturer's instructions.
8.3.6 Vapor retarder material that is cut, torn, or punctured during installation shall be repaired before the assembly is closed.
8.3.7 Repairs to the vapor retarder shall lap at least 6 inches and be taped with a compatible tape specified by the vapor retarder manufacturer.

8.4 Vapor Retarder for Roofing Assemblies

NOTE In low-slope roofing assemblies, a vapor retarder installed below the roof insulation prevents warm, humid interior air from reaching the cold insulation layer and condensing. (8.4.1)
NOTE This is critical in climate zones 5–8 and in buildings with high interior humidity (natatoriums, food processing facilities, commercial kitchens). (8.4.2)
Roof Assembly — Vapor Retarder Below Insulationradio
Required — Climate Zone 5–8 or high interior humidity occupancy
Not required — Climate Zone 1–4 standard occupancy
Coordinate with membrane roofing assembly per [[sync/membrane-roofing]]
8.4.3 Roofing vapor retarders shall be specified in coordination with Membrane Roofing.
NOTE This standard addresses only the insulation above the vapor retarder; the vapor retarder substrate material is governed by the roofing assembly standard. (8.4.4)

9 Installation by Assembly Type

9.1 General Installation Requirements

Minimum Substrate Temperature for Installationradio
40°F (4°C) — general minimum for most insulation products
50°F (10°C) — required by some adhesive-applied board systems
Per manufacturer's published requirements for specific product — see submittal
9.1.1 Insulation shall be installed in accordance with the manufacturer's published installation instructions, ASTM C1320 for mineral fiber batt and blanket, and ICC 1100 for spray-applied polyurethane foam.
9.1.2 Where the installation instructions conflict with this standard or the contract documents, the more stringent requirement shall apply.
9.1.3 All substrates receiving insulation shall be clean, dry, and within the manufacturer's specified temperature range.
9.1.4 Substrates with visible moisture, frost, ice, or standing water shall not receive insulation until the moisture condition is corrected and the substrate is within the acceptable temperature range.
9.1.5 Insulation shall not be installed over wet concrete, wet masonry, or wet structural sheathing.

9.2 Wall Assembly — Cavity Insulation

Cavity Insulation — Splitting Around Obstructions Requiredradio
Yes — all wiring, pipes, blocking, and fire stops require split installation
Installer discretion — not contractually required
Cavity Insulation — Batt Size Match to Framing Spacingradio
16-inch on-center framing — 15-inch wide batts
24-inch on-center framing — 23-inch wide batts
24-inch on-center advanced framing — 23-inch wide batts
Per drawings
9.2.1 Mineral fiber batt and blanket installed in stud-framed wall cavities shall fill the cavity completely from stud face to stud face and from bottom plate to top plate, without voids, gaps, or compression.
9.2.2 Insulation shall be split around wiring, blocking, and other obstructions so that insulation fills both sides of the obstruction, and the total installed thickness shall equal the cavity depth.
NOTE Splitting and fitting is the most common Grade I requirement violated in the field — a single batt folded behind a wire rather than split yields a localized void that can reduce the effective R-value of that cavity section by 30 to 50 percent. (9.2.3)
9.2.4 Where batts are installed in two-stud-bay increments, joints between adjacent batts shall be butted tightly without gaps.
9.2.5 Batts at the top and bottom of the cavity shall be cut to length and fitted without fold-over or compression.
9.2.6 Batt width shall match the stud spacing so the batt is friction-fit snugly.
9.2.7 In masonry cavity wall construction, mineral wool or glass fiber batt insulation installed in the cavity between the inner wythe and the outer masonry veneer shall be secured against sagging over the full height of the cavity by insulation clips, self-adhering insulation, or a continuous horizontal support at floor lines.
NOTE Unsecured batts in tall masonry cavities settle over time, creating insulation-free zones at the top of each floor level that are significant thermal leaks. (9.2.8)

9.3 Wall Assembly — Continuous Exterior Insulation

Continuous Insulation — Number of Layers (for joint staggering)radio
Single layer (minimum — joints taped; acceptable for CI ≤ 1.5 in.)
Two layers with offset joints (required for CI ≥ 2.0 in.)
Three or more layers (high-performance assemblies, CI ≥ 4.0 in.)
Continuous Insulation Attachment Methodselect
Long-shank screws through gypsum board or clip system — drawing governs
Adhesive (below 1.0-inch thickness, non-structural — confirm with manufacturer)
Mechanical clips and rail system (MEPS or equivalent — coordinates with cladding attachment)
Per drawings — continuous insulation attachment detail
9.3.1 Rigid board continuous insulation (XPS, EPS, polyiso, or mineral wool board) applied to the exterior face of the structural wall sheathing shall be installed in full-coverage courses with staggered joints in multiple layers and with all joints offset a minimum of 12 inches both horizontally and vertically.
9.3.2 Joints shall not be through-aligned between layers, because aligned joints create a thermal stripe that significantly reduces the thermal benefit of the continuous insulation layer.
9.3.3 Board joints in continuous exterior insulation shall be taped with a compatible tape to minimize air infiltration at joints, unless the exterior air barrier is provided by a separate fluid-applied or sheet-applied layer outboard of the insulation.
9.3.4 Where the taped rigid board joints are the primary air barrier, every joint shall be taped including field cuts, perimeter edges at windows, doors, and penetrations, and transitions to adjacent assemblies.
9.3.5 Window and door rough opening perimeters shall receive flexible flashing tape or sealant at the transition between the continuous insulation and the window or door assembly.
9.3.6 The window and door perimeter transition is one of the highest-frequency air leakage locations in the building envelope and shall be specifically detailed on the drawings and carefully executed in the field.

9.4 Roof Assembly — Low-Slope

Roof Insulation — Layer Configurationradio
Single layer (≤2.5 in. total — low R-value applications)
Two layers with offset joints (required for total thickness >2.5 in.)
Three or more layers (high R-value assembly, ≥R-30)
Roof Insulation Attachment — First Layerradio
Mechanically fastened per manufacturer's table (fastener type, count, pattern per drawings)
Hot-mopped in Type III or IV asphalt (BUR assemblies)
Low-rise foam adhesive (SPF roofing systems and single-ply)
Per drawings — roof assembly insulation attachment detail
Roof Insulation Attachment — Subsequent Layer(s)radio
Mechanically fastened through all layers per manufacturer's requirements
Low-rise foam adhesive (subsequent layers over mechanically fastened base layer)
Hot-mopped over base layer
Per drawings — roof assembly insulation attachment detail
Tapered Insulation for Positive Drainageradio
Required — manufacturer to provide layout drawing
Not required — structural slope provides required drainage
Partial — tapered insulation at sumps and low points only
9.4.1 Polyisocyanurate or XPS board insulation in low-slope roofing assemblies shall be installed in accordance with the requirements of the roofing assembly, as governed by Membrane Roofing, and with the roofing manufacturer's published requirements for the insulation substrate.
9.4.2 Roof insulation shall be installed in at least two layers for thicknesses above 2.5 inches total, with joints offset 12 inches minimum both in the plane of the roofing and between the two layers, so that no through-joint path exists.
NOTE Through-aligned joints create visible ridges in the membrane and points of accelerated moisture accumulation. (9.4.3)
9.4.4 Tapered insulation for positive slope drainage at low-slope roofs shall be installed per the tapered insulation layout drawing, which shall be provided by the tapered insulation system supplier and coordinated with the roofing assembly.
9.4.5 The minimum required slope for drainage shall be 1/4 inch per foot unless the roofing system manufacturer approves a lesser slope.
9.4.6 Insulation panels shall be installed sequentially following the drainage direction; random installation that disrupts the taper gradient shall not be permitted.

9.5 Roof Assembly — Steep-Slope (Attic)

9.5.1 In attic assemblies, insulation may be installed either at the roof deck plane (unvented attic, insulation between and over rafters) or at the ceiling plane (vented attic, insulation over the top plate).
Steep-Slope Roof / Attic Insulation Strategyradio
Vented attic — insulation at ceiling plane with ventilation baffles
Unvented attic — closed-cell SPF at roof deck plane (interior application)
Unvented attic — rigid board at roof deck plane (above-deck application)
Hybrid — closed-cell SPF at roof deck + supplemental blown or batt at ceiling plane
9.5.2 Where the attic is vented, insulation shall be installed at the ceiling plane and shall not block the eave vents or ridge vents.
9.5.3 Baffles shall be installed at each rafter bay from the top-of-wall plate to at least 12 inches above the top of the insulation, maintaining a clear ventilation channel of minimum 1-inch depth.
9.5.4 Where blown-in or batt insulation is used in a vented attic, minimum installed depth shall be maintained uniformly across the entire ceiling area including above the top plates, at blocking and bridging, and in any knee-wall areas.
9.5.5 Access hatches to the attic shall be insulated to match the ceiling R-value with rigid insulation, insulated hatch covers, or a combination.
NOTE Uninsulated attic hatches are a common but significant thermal bypass. (9.5.6)

9.6 Floor and Crawl Space

Floor Insulation Supportradio
Wire support rods at 18-inch on-center maximum
Plastic support net or mesh secured to joists
Rigid board adhered to subfloor underside (no support required)
Per installer's approved method — confirm with Architect
9.6.1 Insulation installed between floor joists over unconditioned crawl spaces or garages shall be friction-fit tightly against the subfloor and held securely in place by insulation supports (wire rods, netting, or strips) spaced at 18 inches on center maximum so that the insulation cannot sag or fall.
NOTE Insulation that sags away from the subfloor creates a significant convective loop and may also create a habitat for pests. (9.6.2)
9.6.3 Where the floor insulation facing is a vapor retarder, the facing shall face toward the heated space (upward in a floor over a crawl space).
9.6.4 In conditioned crawl spaces where the insulation is installed on the crawl space walls rather than the floor joists, rigid board or closed-cell SPF shall be applied to the interior of the foundation wall from the sill plate down to the footing.
9.6.5 The crawl space wall insulation shall extend from 24 inches below grade to the top of the footing and shall be protected from mechanical damage in accessible crawl spaces.
9.6.6 Foundation wall insulation shall be detailed to prevent moisture wicking from the concrete into the insulation by using materials with adequate drainage capability or by detailing appropriate drainage planes.

9.7 Below-Grade Foundation Walls and Slab Edge

Below-Grade Exterior Foundation Insulation Typeradio
Extruded polystyrene (XPS) — ASTM C578, Type II minimum
Expanded polystyrene (EPS) — ASTM C578, Type II minimum
Mineral wool board — ASTM C612 (best moisture and drainage performance)
Not used (insulation on interior face of foundation wall)
Below-Grade Insulation — Protection Above Graderadio
Concrete parging — minimum 3/4 in. Portland cement on metal lath
Rigid protection board — minimum 1/4 in. at grade and above
Dimple drainage mat with protection board at grade
Per drawings — foundation insulation detail at grade
Under-Slab Insulation — Compressive Resistanceselect
15 psi minimum (EPS Type II or XPS Type XIII — residential)
25 psi minimum (EPS Type IX or XPS Type IV — light commercial)
40 psi minimum (EPS Type XIV or XPS Type VII — heavy commercial)
Per drawings — structural engineer's direction
9.7.1 Rigid insulation on the exterior of below-grade foundation walls shall be protected from physical damage above grade and from UV degradation at the grade line.
9.7.2 Protection board (minimum 1/4-inch rigid board), dimple drainage mat, or concrete parging shall be applied over the rigid insulation from the top of the insulation down to 6 inches below grade at minimum.
9.7.3 Above-grade exposure of XPS or polyiso foam plastic is not permitted; mineral wool board or specifically listed below-grade exterior products shall be used where the insulation will remain exposed above grade.
9.7.4 Under-slab insulation shall be rigid board (XPS, EPS, or mineral wool board) rated for the compressive loads imposed by the slab and contents.
9.7.5 The minimum compressive resistance for under-slab insulation shall be 15 psi (EPS Type II, XPS Type XIII or higher) for residential-scale uniform floor loads; heavier commercial or warehouse loads shall require higher-compressive-strength products per the structural engineer's direction.
9.7.6 Under-slab insulation shall be installed in continuous coverage without gaps; gaps at column footings, thickened slab edges, and pipe penetrations are common installation defects that create localized thermal short circuits.

10 Continuous Insulation and Thermal Bridging

10.1 Defining Continuous Insulation

NOTE Continuous insulation (ci) is insulation that extends across all structural members in the assembly without thermal bridges other than fasteners and service openings, as defined by ASHRAE 90.1. (10.1.1)
NOTE By eliminating the thermal bridge created by framing members, continuous insulation dramatically improves the whole-assembly R-value compared to cavity-only insulation of the same nominal value. (10.1.2)
NOTE The benefit of continuous insulation increases with framing fraction; metal-framed walls with continuous exterior insulation achieve whole-wall R-values that would be nearly impossible to approach with cavity insulation alone. (10.1.3)
NOTE ASHRAE 90.1 prescriptive tables for above-grade walls in climate zones 3–8 require continuous insulation in combination with (or as an alternative to) cavity insulation, and the specific minimum ci thickness and total R-value depend on the climate zone, the framing material (wood vs. metal stud), and the framing spacing. (10.1.4)
10.1.5 The project energy code compliance documentation shall identify the minimum ci R-value for each above-grade wall type.

10.2 Thermal Bridging by Framing Material

NOTE Wood stud walls have a framing fraction of approximately 20–25 percent at 16 inches on center. (10.2.1)
NOTE The R-value of wood is approximately R-1.4 per inch, which is substantially lower than that of the cavity insulation it displaces. (10.2.2)
NOTE A 2×6 wood-framed wall with R-19 batts achieves a whole-wall effective R-value of approximately R-15 due to framing; continuous exterior insulation of R-5 to R-7.5 brings the whole-wall assembly close to R-20 to R-22. (10.2.3)
Wall Framing Material (for thermal bridge assessment)radio
Wood stud — standard thermal bridging correction applies
Light-gauge steel stud — severe thermal bridging; continuous insulation critical
Structural steel — continuous insulation required; coordinate with structural
Masonry or concrete — negligible framing bridge; cavity insulation not applicable
Continuous Insulation Strategy for Above-Grade Wallsradio
Exterior rigid board CI — outboard of sheathing, inboard of cladding
Exterior SPF CI — spray-applied to exterior sheathing
Thermally broken Z-girt or hat channel system with exterior CI
Interior rigid board CI — inboard of framing (limited effectiveness for metal stud)
No continuous insulation required — prescriptive exception or climate zone 1–2
NOTE Metal stud walls have significantly more severe thermal bridging because steel has very high thermal conductivity — approximately 320 times that of wood — so that a metal-framed wall with R-19 batt insulation between studs achieves an effective whole-wall R-value of only approximately R-8 to R-10 due to thermal bridging through the steel studs, even though the nominal cavity R-value is R-19. (10.2.4)
10.2.5 Continuous exterior insulation is essential in metal-framed construction, and the required ci R-value for metal stud walls is substantially higher than for comparable wood-framed walls to achieve the same whole-wall performance.

10.3 Fastener and Cladding Attachment Thermal Penalty

NOTE When rigid continuous insulation is fastened through by long structural screws to attach cladding or rain screen systems, each fastener penetrating the insulation is a thermal bridge whose magnitude depends on the fastener material (steel vs. nylon or stainless), fastener diameter, spacing, and the thickness of insulation penetrated. (10.3.1)
CI Fastener Thermal Bridging Correctionradio
Accounted for in energy model — see energy compliance report
Thermally broken fastener system specified to minimize correction
Standard steel fastener — thermal penalty accepted per ASHRAE 90.1 Appendix A
10.3.2 For ASHRAE 90.1 performance compliance, the thermal penalty of fasteners through continuous insulation shall be accounted for in the assembly U-factor calculation.
10.3.3 Nylon-tipped or thermally broken fastening systems reduce the fastener thermal penalty and shall be used where drawings or specifications require it.

10.4 Common Thermal Bridging Defects and RFI Sources

10.4.2 Drawings shall detail each of these continuous insulation conditions before construction begins.
10.4.3 Where drawings are silent, the Contractor shall submit an RFI and shall not close the insulation layer until a detailed resolution is documented.
NOTE Improper field resolutions at CI transitions and penetrations are among the most significant thermal defect sources in modern construction. (10.4.4)

11 Inspection

11.1 Pre-Installation Inspection

Pre-Installation Checklistcheckbox
Framing complete and inspected
All rough MEP work installed and inspected
Sheathing and air barrier complete and dry
Substrate temperature within manufacturer's range
Delivered insulation products match approved submittals
11.1.1 Before insulation installation begins in each assembly area, the Contractor shall inspect and confirm that all framing is complete, plumb, and at the correct spacing; that all rough mechanical, electrical, and plumbing work is installed and inspected; that all substrate sheathing is fastened and any required air barrier membrane is applied; that the substrate is dry and within the temperature range for the insulation product; and that the insulation products on-site match the approved submittals.

11.2 In-Progress Inspection

Third-Party Inspection Required Before Closing Assembliesradio
Yes — HERS rater inspection required for energy code documentation
Yes — Owner's independent inspector required
Yes — AHJ rough framing and insulation inspection required
Contractor self-certification only
11.2.1 Insulation installation shall be subject to in-progress inspection before assemblies are closed.
11.2.2 In-progress inspection shall confirm that all cavities are uniformly filled without voids or compression (RESNET Grade I as required), that all batts are properly split around obstructions, that continuous insulation boards are in full contact with the substrate without gaps or hollow spots, that all taped CI board joints are fully adhered, and that vapor retarder facing and any separate vapor retarder membrane are intact and oriented correctly.
11.2.3 The Architect, Owner's designated inspector, or the HERS rater shall have the right to observe insulation installation at any time before assemblies are closed.
11.2.4 The Contractor shall notify the designated inspector at least 48 hours before any insulation is scheduled to be concealed by finishes or cladding.

11.3 Blower Door and Air Barrier Testing

Air Barrier Pressurization Testing Requiredradio
Yes — residential blower door test per IECC Section R402.4 (ACH50 limit per climate zone)
Yes — commercial whole-building or compartmentalized test per IECC C402.5
No — project exempt from pressurization testing under adopted code
Maximum Allowable Air Leakage Raterange
ACH50
17
12357
Default: 3 ACH50
Per drawings
11.3.1 Where required by the adopted energy code (IECC Section R402.4 for residential or IECC Section C402.5 for commercial), air barrier continuity shall be verified by a whole-building pressurization test (blower door test) after the building envelope is complete and before insulation and finishes conceal the air barrier layer.
11.3.2 The maximum allowable air leakage rate shall be per the adopted code and shall be as noted on the energy compliance drawings or energy code report.

11.4 SPF Thickness and Density Verification

SPF Core Sample Frequencyradio
One core per 500 square feet of applied area (high quality control)
One core per 1,000 square feet of applied area (standard)
One core per 2,000 square feet of applied area (minimum)
11.4.1 Spray-applied polyurethane foam shall be verified for thickness and density by core sampling after application and before the foam is concealed.
11.4.2 SPF cores shall be taken in the locations and at the frequency established in the pre-application meeting.
11.4.3 Minimum acceptable SPF thickness shall be the specified minimum minus 1/4 inch at any single core location.
11.4.4 Minimum acceptable SPF density shall be within the range specified by ASTM C1029 for the product type.
11.4.5 Cores that do not meet minimum thickness or density requirements shall trigger additional cores in the surrounding area and remedial application as directed by the Architect.

11.5 Thermal Imaging

NOTE Infrared thermographic scanning of the completed building envelope is a powerful tool for identifying insulation voids, thermal bridges, and air leakage pathways that are not visible by conventional inspection. (11.5.1)
Infrared Thermographic Inspectionradio
Required — Owner's thermographer, schedule with Contractor
Contractor option — may use as self-QC measure
Not required
11.5.2 Thermographic scanning requires a minimum temperature differential of 10°F between interior and exterior and shall be conducted during heating season in cold climates or cooling season in hot climates.
11.5.3 Where infrared scanning is specified as a quality assurance measure, the Contractor shall provide access to the building interior and shall coordinate the timing with the Owner's or Architect's thermographer.

12 Warranty

12.1 Manufacturer's Material Warranty

NOTE Typical manufacturer warranties for rigid board insulation products are 10 to 25 years for resistance to physical degradation; the specific warranty coverage and exclusions vary by manufacturer and product. (12.1.1)
NOTE Spray-applied polyurethane foam systems typically carry a material warranty of 10 years from the system manufacturer when installed by a certified applicator in conformance with manufacturer requirements. (12.1.2)
Manufacturer's Material Warranty Period — Rigid Board Insulationselect
10 years
15 years
20 years
25 years
Per manufacturer's standard warranty
12.1.3 Insulation products carrying a manufacturer's material warranty against defects in materials shall be warranted to the Owner.
12.1.4 The Contractor shall submit warranty documents as part of closeout submittals.
12.1.5 The Contractor shall review the applicable warranty before procurement, since the specific warranty coverage and exclusions vary by manufacturer and product.
NOTE Warranty coverage for SPF is often conditional on the foam being covered by a compatible protective coating or covered by finished materials; uncovered and UV-exposed SPF is not warranted and will physically degrade within 1–2 years of UV exposure. (12.1.6)

12.2 Installation Warranty

Installation Warranty Periodselect
1 year from substantial completion
2 years from substantial completion
12.2.1 The Contractor shall warrant the insulation installation against defects in workmanship, including voids, compression, improper facing orientation, unsealed joints, and failure to achieve specified R-value in completed assemblies, for the project warranty period from the date of substantial completion.
12.2.2 Where blower door testing reveals air leakage above the specified maximum during the warranty period, the Contractor shall identify and correct the leakage source and re-test at no additional cost to the Owner.
12.2.3 Where thermal imaging reveals insulation voids or deficiencies during the warranty period, the Contractor shall open the affected assembly, correct the deficiency, and restore the assembly at no additional cost to the Owner, unless the deficiency is demonstrably due to post-completion Owner modifications.

12.3 Performance Documentation

Energy Code Compliance Documentation Provided at Closeoutcheckbox
Contractor certificate of compliance (signed)
Energy code compliance report / compliance certificate
Blower door test results
HERS rater inspection report
AHJ inspection approvals for insulation rough-in
Infrared thermographic report (if required)
SPF core sample test reports
12.3.1 The Contractor shall maintain and provide to the Owner at closeout a complete set of energy code compliance documentation, including the certificate of compliance, the energy code report, blower door test results, HERS rater inspection reports where applicable, and any other documentation required by the AHJ for energy code compliance certification.
12.3.2 This energy code compliance documentation is required for certificate of occupancy in many jurisdictions and shall be treated as a contract deliverable.

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