Building Thermal Insulation
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 6
to Rev 7
in Building Thermal Insulation.
---
title: Building Thermal Insulation
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### 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). {note}
+### The energy code compliance path — prescriptive, trade-off, or performance — used to establish the project's minimum R-values shall be specified.
+
```datasheet
+label: Energy Code Compliance Path
+type: radio
+options:
+ - "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)"
+default: "Prescriptive (minimum R-values from IECC Table R402.1.2 or ASHRAE 90.1 Table 5.5)"
+```
+
+### 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.
+
+```datasheet
label: Project Climate Zone (IECC/ASHRAE)
type: select
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```
−```datasheet
−label: Energy Code Compliance Path
−type: radio
−options:
− - "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)"
−default: "Prescriptive (minimum R-values from IECC Table R402.1.2 or ASHRAE 90.1 Table 5.5)"
−```
−
−### 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.
−
### The prescriptive minimum R-values for the project climate zone shall be [[drawing: as tabulated on the energy compliance drawings or energy code compliance report]].
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### These are not the same. {note}
+### The basis for the wall assembly's thermal performance shall be specified, and shall be the whole-wall effective R-value or simulated performance, not the nominal cavity R-value.
+
```datasheet
label: Wall Assembly Thermal Performance Basis
…14 unchanged lines
### The following datasheet elements record the specified minimum R-values for submittal verification and field inspection documentation. {note}
+### Design R-values for each assembly type shall be [[drawing: as indicated on the building envelope drawings and energy code compliance documentation]].
+
```datasheet
label: Roof/Ceiling Assembly — Specified R-Value
…68 unchanged lines
```
−### Design R-values for each assembly type shall be [[drawing: as indicated on the building envelope drawings and energy code compliance documentation]].
−
# Insulation Materials {toc}
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### Mineral fiber includes glass fiber (fiberglass) and mineral wool (rock or slag wool) products. {note}
+### The mineral fiber product type — batt, blanket, or board — used for each application shall be specified, consistent with the ASTM standard governing that product.
+
```datasheet
label: Mineral Fiber Batt/Blanket Product Type
…7 unchanged lines
```
+### The nominal R-value per inch of the mineral fiber batt or blanket product shall be specified, consistent with the product type selected for the application.
+
```datasheet
label: Mineral Fiber Batt/Blanket — Nominal R-Value per Inch
…7 unchanged lines
```
+### The vapor retarder facing, if any, for mineral fiber batt or blanket insulation shall be specified based on the assembly's vapor control requirements.
+
```datasheet
label: Mineral Fiber Batt/Blanket — Facing
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### 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. {note}
−```datasheet
−label: XPS Board — ASTM C578 Compressive Resistance Type
−type: select
−options:
− - "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"
−default: "Type II — 15 psi (general below-grade and above-grade CI)"
−```
+### The nominal thickness of extruded polystyrene board insulation shall be specified to achieve the assembly R-value required for the application.
```datasheet
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### 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.
+```datasheet
+label: XPS Board — ASTM C578 Compressive Resistance Type
+type: select
+options:
+ - "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"
+default: "Type II — 15 psi (general below-grade and above-grade CI)"
+```
+
### 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.
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### 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. {note}
+### Expanded polystyrene rigid board insulation shall conform to ASTM C578 (EPS types).
+
```datasheet
label: EPS Board — Density and Compressive Strength
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```
−### Expanded polystyrene rigid board insulation shall conform to ASTM C578 (EPS types).
−
### 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. {note}
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### 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. {note}
+### The ASTM C1289 type and facing of polyisocyanurate board insulation shall be specified for each application where polyiso is used.
+
```datasheet
label: Polyisocyanurate Board — ASTM C1289 Type (Facing)
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```
−```datasheet
−label: Polyisocyanurate Board — Specified LTTR R-Value
−type: range
−unit: R (h·ft²·°F/Btu)
−options:
− min: 6.5
− max: 40
− setpoints: [6.5, 13, 16, 19.5, 25, 30, 35, 40]
−drawing_ref: true
−default: 25
−```
+### The nominal thickness of polyisocyanurate board insulation shall be specified to achieve the assembly R-value required for the application.
```datasheet
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### 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.
+```datasheet
+label: Polyisocyanurate Board — Specified LTTR R-Value
+type: range
+unit: R (h·ft²·°F/Btu)
+options:
+ min: 6.5
+ max: 40
+ setpoints: [6.5, 13, 16, 19.5, 25, 30, 35, 40]
+drawing_ref: true
+default: 25
+```
+
### 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. {note}
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### 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. {note}
−```datasheet
−label: SPF Type
−type: radio
−options:
− - "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"
−default: "Closed-cell SPF (ccSPF) — ASTM C1029, approximately R-6.5/inch, Class II vapor retarder at 2 in."
−```
+### The minimum applied thickness of spray-applied polyurethane foam insulation shall be specified to achieve the assembly R-value required for the application.
```datasheet
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```
+### The minimum applied density of spray-applied polyurethane foam insulation shall be specified, consistent with the cell type selected for the application.
+
```datasheet
label: SPF Minimum Applied Density
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```
+### Spray-applied polyurethane foam insulation shall conform to ASTM C1029 for closed-cell SPF (ccSPF) and to ICC 1100 for open-cell SPF (ocSPF).
+
```datasheet
−label: SPF Thickness Verification Method
+label: SPF Type
type: radio
options:
− - "Probe and measure during application by installer"
− - "Third-party core sampling after installation"
− - "Both probe-during-application and third-party core sampling"
−default: "Both probe-during-application and third-party core sampling"
+ - "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"
+default: "Closed-cell SPF (ccSPF) — ASTM C1029, approximately R-6.5/inch, Class II vapor retarder at 2 in."
```
−### Spray-applied polyurethane foam insulation shall conform to ASTM C1029 for closed-cell SPF (ccSPF) and to ICC 1100 for open-cell SPF (ocSPF).
−
### Closed-cell SPF applied at 2 inches meets the vapor retarder requirement of many climate zones as a Class II retarder.
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### 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.
+```datasheet
+label: SPF Thickness Verification Method
+type: radio
+options:
+ - "Probe and measure during application by installer"
+ - "Third-party core sampling after installation"
+ - "Both probe-during-application and third-party core sampling"
+default: "Both probe-during-application and third-party core sampling"
+```
+
### Core locations shall be patched by the SPF installer immediately after sampling with the same SPF material.
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### The standard reporting convention is "FSI/SDI" (e.g., 25/450). {note}
+### Insulation materials required to demonstrate surface burning characteristics shall be tested per ASTM E84 (Steiner Tunnel test).
+
```datasheet
label: Required ASTM E84 Classification — Flame Spread Index (FSI)
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```
−### Insulation materials required to demonstrate surface burning characteristics shall be tested per ASTM E84 (Steiner Tunnel test).
−
### 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. {note}
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### Foam plastic insulation installed in buildings regulated by the IBC is subject to IBC Section 2603. {note}
+### 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.
+
+### 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.
+
+### 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. {note}
+
+### 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.
+
+### 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.
+
+### 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.
+
```datasheet
label: NFPA 285 Assembly Test Documentation
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```
+### 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.
+
```datasheet
label: Foam Plastic — Ignition Barrier in Attic/Crawl Space
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```
−### 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.
−
−### 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.
−
−### 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. {note}
−
−### 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.
−
−### 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.
−
−### 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.
−
−### 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.
−
# Vapor Retarders and Air Barrier Coordination {toc}
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### IBC Section 1405.3 and IRC Section R702.7 establish the climate-zone vapor retarder requirements set out below. {note}
+### 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.
+
```datasheet
label: Continuous Exterior Insulation R-Value / Total Wall R-Value Ratio — IBC 1405.3.3 Compliance
…6 unchanged lines
```
−### 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.
−
### 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. {note}
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### 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. {note}
+### 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.
+
```datasheet
label: Air Barrier System Coordination
…7 unchanged lines
```
−### 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.
−
### 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.
…7 unchanged lines
### This is critical in climate zones 5–8 and in buildings with high interior humidity (natatoriums, food processing facilities, commercial kitchens). {note}
+### Roofing vapor retarders shall be specified in coordination with [[sync/membrane-roofing]].
+
```datasheet
label: Roof Assembly — Vapor Retarder Below Insulation
…6 unchanged lines
```
−### Roofing vapor retarders shall be specified in coordination with [[sync/membrane-roofing]].
−
### This standard addresses only the insulation above the vapor retarder; the vapor retarder substrate material is governed by the roofing assembly standard. {note}
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### 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. {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. {note}
+
+### 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.
+
```datasheet
label: Wall Framing Material (for thermal bridge assessment)
…19 unchanged lines
```
−### 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. {note}
−
−### 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.
−
## Fastener and Cladding Attachment Thermal Penalty {toc}
### 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. {note}
+### For ASHRAE 90.1 performance compliance, the thermal penalty of fasteners through continuous insulation shall be accounted for in the assembly U-factor calculation.
+
```datasheet
label: CI Fastener Thermal Bridging Correction
…6 unchanged lines
```
−### For ASHRAE 90.1 performance compliance, the thermal penalty of fasteners through continuous insulation shall be accounted for in the assembly U-factor calculation.
−
### Nylon-tipped or thermally broken fastening systems reduce the fastener thermal penalty and shall be used where drawings or specifications require it.
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### 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. {note}
+### 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.
+
+### 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.
+
```datasheet
label: Infrared Thermographic Inspection
…6 unchanged lines
```
−### 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.
−
−### 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.
−
# Warranty {toc}
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### 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. {note}
+### Insulation products carrying a manufacturer's material warranty against defects in materials shall be warranted to the Owner.
+
```datasheet
label: Manufacturer's Material Warranty Period — Rigid Board Insulation
…8 unchanged lines
```
−### Insulation products carrying a manufacturer's material warranty against defects in materials shall be warranted to the Owner.
−
### The Contractor shall submit warranty documents as part of closeout submittals.
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### This energy code compliance documentation is required for certificate of occupancy in many jurisdictions and shall be treated as a contract deliverable.