+---
+title: Under-Slab Vapor Barriers
+category: Structural / Concrete
+toc_depth: 3
+description: >
+ When to use: Vapor barriers and vapor retarders installed in direct contact with soil or
+ granular fill beneath concrete slabs-on-grade in commercial, institutional, and residential
+ construction. Covers material selection, ASTM E1745 performance-class determination, true
+ vapor barriers (less than or equal to 0.01 perms) for high-sensitivity occupancies, placement
+ sequence, lap and seam requirements, penetration sealing, repair, and coordination with
+ concrete placement.
+ Not intended for: structural slab design and granular sub-base design/compaction (use
+ sync/slab-on-grade and sync/site-rough-grading); concrete mix, placement, curing, and
+ finishing (use sync/cast-in-place-concrete); below-grade wall waterproofing and slabs under
+ hydrostatic pressure (separate waterproofing assemblies); above-slab flooring vapor layers
+ (use the flooring assembly, e.g. sync/epoxy-flooring); generic wall/roof vapor retarders
+ (use sync/vapor-retarders).
+---
+
+# Scope {toc}
+
+## This Standard covers water vapor retarders and water vapor barriers installed in direct contact with soil or granular fill beneath concrete slabs-on-grade. {note}
+
+## It addresses material selection (single-ply polyethylene sheet, multi-layer reinforced laminate, and bituminous sheet), determination of the ASTM E1745 performance class, the elevated requirements for true vapor barriers serving moisture-sensitive occupancies, placement sequence, lap and seam construction, penetration sealing, repair before concrete placement, and coordination with the concrete pour. {note}
+
+## This Standard applies wherever the finished slab will receive moisture-sensitive flooring, coatings, or adhesives, will be climate-controlled, or where code requires floor dampproofing. {note}
+
+## Resilient flooring, sheet vinyl, wood, carpet tile with moisture-sensitive adhesives, epoxy and urethane coatings, and most adhered finishes fail when slab moisture vapor migrates upward unchecked. ASTM F710 requires an effective vapor retarder in direct contact with the underside of any slab that will receive resilient flooring, and IRC R506.2.3 requires a Class A retarder beneath residential slabs on ground. The under-slab membrane is the primary, permanent line of moisture control because it cannot be added after the slab is placed. {note}
+
+## This Standard does not cover the following adjacent scopes. {note}
+
+## Each excluded item is owned by another standard and is called out here to fix the boundary at bid time: {note}
+- Structural design of the slab itself (thickness, reinforcement, joints) and granular sub-base design and compaction — see [[sync/slab-on-grade]] and [[sync/site-rough-grading]].
+- Concrete mix design, placement, curing, and finishing — see [[sync/cast-in-place-concrete]].
+- Waterproofing membranes on the exterior face of below-grade walls, and occupied below-grade slabs subject to hydrostatic pressure — those are wall and plaza waterproofing assemblies, not under-slab vapor control.
+- Above-slab vapor control layers that are part of a flooring system (sheet or liquid-applied moisture-mitigation coatings over a cured slab) — those belong with the flooring assembly, e.g. [[sync/epoxy-flooring]].
+- Generic vapor retarders used in wall or roof assemblies — see [[sync/vapor-retarders]].
+
+## Terminology used in this Standard is defined by permeance, not by trade habit. {note}
+
+## The terms "vapor barrier" and "vapor retarder" are frequently used interchangeably in the field, which creates ambiguity at bid time. This Standard fixes the meanings: {note}
+- Vapor retarder: a membrane with a water vapor permeance less than or equal to 0.1 perms (after conditioning), meeting ASTM E1745 Class A, B, or C.
+- Vapor barrier: a membrane with a water vapor permeance less than or equal to 0.01 perms, the threshold ACI 302.2R associates with slabs receiving moisture-sensitive flooring.
+- Permeance is measured per ASTM E96/E96M and reported in U.S. perms.
+
+## Where this Standard refers to "the membrane," it means the under-slab vapor retarder or vapor barrier sheet, whichever class the Contract Documents require. {note}
+
+# Referenced Standards {toc}
+
+## Materials, products, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited in the Contract Documents.
+
+## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ASTM E1745-17 | Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete Slabs |
+| ASTM E1643 | Selection, Design, Installation, and Inspection of Water Vapor Retarders Used in Contact with Earth or Granular Fill under Concrete Slabs |
+| ASTM E1993 | Bituminous Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete Slabs |
+| ASTM E96/E96M | Water Vapor Transmission of Materials |
+| ASTM E154 | Water Vapor Retarders Used in Contact with Earth Under Concrete Slabs, on Walls, or as Ground Cover |
+| ASTM F710 | Preparing Concrete Floors to Receive Resilient Flooring |
+| ASTM F2170 | Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes |
+| ACI 302.1R | Guide for Concrete Floor and Slab Construction |
+| ACI 302.2R | Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials |
+| IBC | International Building Code (Section 1805.2.2, Floors Below Grade) |
+| IRC | International Residential Code (Section R506.2.3, Vapor Retarder) |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following action submittals for review before delivering material to the site:
+- Product data for the proposed membrane, seam tape, pipe boots, and mastic, including manufacturer, product designation, nominal thickness, and material type.
+- Manufacturer's certified test report demonstrating the membrane meets the required ASTM E1745 class for tensile strength, puncture resistance, and permeance, with permeance reported per ASTM E96/E96M.
+- For true vapor barrier applications, certified permeance test data demonstrating permeance less than or equal to 0.01 perms.
+- Samples of the membrane and the manufacturer's seam tape.
+- Shop drawings or manufacturer details for lap construction, penetration boots and collars, perimeter termination, and repair patching.
+- Statement of compatibility confirming the seam tape, pipe boots, and mastic are produced or approved by the membrane manufacturer for use with the proposed membrane.
+
+```datasheet
+label: Action Submittals
+type: checkbox
+options:
+ - Product data (membrane, tape, boots, mastic)
+ - ASTM E1745 class certified test report
+ - Permeance test data (E96/E96M)
+ - Samples (membrane and seam tape)
+ - Detail drawings (laps, penetrations, termination, repair)
+ - Compatibility statement (tape/boots/mastic)
+default:
+ - Product data (membrane, tape, boots, mastic)
+ - ASTM E1745 class certified test report
+ - Permeance test data (E96/E96M)
+ - Detail drawings (laps, penetrations, termination, repair)
+ - Compatibility statement (tape/boots/mastic)
+```
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following informational submittals:
+- Manufacturer's printed installation instructions, including lap width, sealing method, and maximum permitted exposure interval before concrete placement.
+- Field inspection report confirming the membrane was installed and repaired before concrete placement, per ASTM E1643.
+- For radon-zone projects, coordination documentation confirming the membrane type and penetration sealing are compatible with the sub-slab depressurization system.
+
+```datasheet
+label: Informational Submittals
+type: checkbox
+options:
+ - Manufacturer installation instructions
+ - Pre-pour field inspection report (E1643)
+ - Radon system coordination documentation
+default:
+ - Manufacturer installation instructions
+ - Pre-pour field inspection report (E1643)
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following closeout submittals:
+- Post-cure slab relative humidity test results per ASTM F2170 demonstrating the slab meets the flooring or adhesive manufacturer's maximum relative humidity before flooring installation.
+- Documentation of any membrane repairs performed, with locations.
+
+```datasheet
+label: Closeout Submittals
+type: checkbox
+options:
+ - ASTM F2170 relative humidity test results
+ - Membrane repair documentation
+default:
+ - ASTM F2170 relative humidity test results
+```
+
+# Quality Assurance {toc}
+
+## The membrane manufacturer shall be a firm regularly engaged in producing under-slab vapor retarders meeting ASTM E1745.
+
+## The Installer shall be experienced in installing under-slab vapor retarders and shall follow the membrane manufacturer's printed instructions and ASTM E1643.
+
+## A pre-installation conference shall be held before membrane installation to confirm sub-base readiness, lap and sealing method, penetration details, and the planned interval between membrane installation and concrete placement.
+
+## The interval between installing the membrane and placing concrete is the single most common source of field damage, so it is fixed in advance rather than left to the pour schedule. UV exposure, wind uplift, and construction traffic degrade polyethylene over time, and the membrane is buried and unrepairable once concrete is placed. {note}
+
+## The membrane shall be inspected for tears, punctures, and open seams immediately before concrete placement.
+
+## All defects found during the pre-pour inspection shall be repaired before concrete is placed.
+
+## Inspection of the installed membrane shall conform to ASTM E1643.
+
+## Where the project's structural or geotechnical scope designates the under-slab vapor retarder as an item subject to special inspection, coordinate the inspection and reporting with [[sync/special-inspections-and-testing]]. {note}
+
+# Performance and Classification {toc}
+
+## ASTM E1745 Performance Class {toc}
+
+### The membrane shall meet ASTM E1745 for the performance class required by the Contract Documents.
+
+### ASTM E1745 sorts retarders into three classes by tested mechanical performance. All three classes share the same maximum permeance after conditioning (less than or equal to 0.1 perms); the classes differ only in tensile strength and puncture resistance, which govern how well the membrane survives installation traffic, rebar chairs, and the concrete pour. Class A is the default for commercial and institutional construction because the membrane must survive being walked on, having reinforcement placed over it, and the pour itself without tearing. {note}
+
+### The minimum required performance class for the membrane shall be Class A unless the Contract Documents specify otherwise.
+
+### Class selection shall account for installation risk, traffic during the pour, subgrade condition, and any flooring-manufacturer requirement that exceeds the code minimum.
+
+### A coarse or angular granular fill, heavy reinforcement, or an aggressive pour sequence all argue for the higher puncture resistance of Class A even where code would permit a lower class. {note}
+
+```datasheet
+label: ASTM E1745 performance class
+type: radio
+options:
+ - Class A
+ - Class B
+ - Class C
+default: Class A
+```
+
+### The membrane shall meet or exceed the following ASTM E1745 minimum properties for the selected class.
+
+### The tabulated values are the ASTM E1745 class minimums. The membrane is selected to the class, not to a mil thickness; the values below are the acceptance criteria, and the manufacturer's certified test report is the proof of compliance. {note}
+
+| Property | Class A | Class B | Class C |
+|----------|---------|---------|---------|
+| Tensile strength (lb/in., min.) | 45 | 30 | 13.6 |
+| Puncture resistance (g, min.) | 2,200 | 1,700 | 475 |
+| Permeance after conditioning (perms, max.) | 0.1 | 0.1 | 0.1 |
+
+## Permeance and the Vapor Barrier Threshold {toc}
+
+### The membrane permeance shall be determined per ASTM E96/E96M and reported in U.S. perms.
+
+### Permeance is the controlling moisture-performance property. ASTM E1745 caps all classes at 0.1 perms, but that ceiling is not low enough for every floor. {note}
+
+### For slabs receiving moisture-sensitive flooring, coatings, or adhesives, the membrane shall have a permeance less than or equal to 0.01 perms (a true vapor barrier per ACI 302.2R) unless the flooring or adhesive manufacturer permits a higher value in writing.
+
+### This is the most consequential pitfall in under-slab vapor control. A membrane that satisfies ASTM E1745 Class A at 0.1 perms can still pass enough vapor to debond resilient flooring adhesives and blister coatings. ACI 302.2R recommends the 0.01-perm threshold for moisture-sensitive finishes. Specifying a class without also specifying the permeance ceiling is therefore insufficient whenever an adhered or coated finish will be installed; always cross-check the flooring or adhesive manufacturer's stated maximum permeance. {note}
+
+### The flooring or adhesive manufacturer's maximum permeance shall be obtained and the membrane selected to satisfy the more stringent of that value and this Standard.
+
+```datasheet
+label: Required maximum permeance
+type: radio
+options:
+ - Vapor barrier, ≤ 0.01 perms (moisture-sensitive flooring)
+ - Vapor retarder, ≤ 0.1 perms (ASTM E1745 class)
+default: Vapor barrier, ≤ 0.01 perms (moisture-sensitive flooring)
+```
+
+### The code-minimum 6-mil polyethylene permitted by IBC Section 1805.2.2 for below-grade floor dampproofing shall not be used where flooring adhesives, coatings, or moisture-sensitive finishes will be installed.
+
+### The IBC below-grade floor dampproofing provision allows a minimum 6-mil polyethylene sheet or approved equivalent. That sheet is inadequate for flooring applications on two counts: its tested performance falls short of the durability needed to survive the pour, and its permeance is far above the threshold for moisture-sensitive finishes. The 6-mil sheet is a dampproofing minimum, not a vapor-control specification. {note}
+
+# Materials {toc}
+
+## Membrane Type {toc}
+
+### The membrane shall be one of the following types, selected to meet the required class and permeance.
+
+### Three material families serve this scope, and they trade off cost, puncture resistance, and achievable permeance: {note}
+- Single-ply polyethylene sheet (HDPE or LLDPE): a single extruded film. Economical; commonly available at 10-mil through 20-mil nominal thickness. Higher mil grades from major manufacturers are Class A capable.
+- Multi-layer reinforced laminate: a woven polyethylene scrim core laminated between two polyethylene films. The scrim core gives high tensile and puncture resistance, so these products are typically Class A and are the workhorse for commercial slabs.
+- Bituminous sheet per ASTM E1993: an asphalt-based composite sheet that achieves true vapor barrier performance (less than or equal to 0.01 perms). Used where the project demands a true vapor barrier for high-sensitivity occupancies.
+
+```datasheet
+label: Membrane type
+type: radio
+options:
+ - Single-ply polyethylene sheet (HDPE/LLDPE)
+ - Multi-layer reinforced laminate (scrim-reinforced)
+ - Bituminous sheet (ASTM E1993)
+default: Multi-layer reinforced laminate (scrim-reinforced)
+```
+
+### The membrane material shall be free of recycled content that would compromise the certified ASTM E1745 properties or the manufacturer's permeance rating.
+
+## Nominal Thickness {toc}
+
+### The membrane nominal thickness shall be as required to meet the specified class and permeance, and not less than the value scheduled.
+
+### Nominal thickness is not the same as ASTM E1745 class. A "15-mil" sheet is not automatically Class A; class is determined by tested tensile, puncture, and permeance performance, and the manufacturer's certified test report is the only proof. Thicker membranes generally resist puncture better and are preferred where the subgrade is coarse or the pour traffic is heavy, but thickness is selected alongside the class requirement, never as a substitute for it. {note}
+
+```datasheet
+label: Membrane nominal thickness
+type: select
+unit: mil
+options:
+ - "10"
+ - "15"
+ - "20"
+default: "15"
+```
+
+### A nominal thickness of 10-mil shall be regarded as a Class C baseline and shall not be specified where Class A performance is required.
+
+### A nominal thickness of 15-mil or greater shall be used where Class A performance is required, subject to certified test confirmation.
+
+## True Vapor Barrier Configuration {toc}
+
+### Where a true vapor barrier is required, the membrane shall be a bituminous sheet per ASTM E1993, or a multi-layer laminate independently certified to a permeance less than or equal to 0.01 perms.
+
+### ASTM E1993 is the product standard for bituminous under-slab vapor barriers and is written around the 0.01-perm threshold. Some heavy multi-layer polyethylene laminates also achieve 0.01 perms; where one is proposed in place of a bituminous sheet, the certified permeance test report is the basis for acceptance. {note}
+
+```datasheet
+label: True vapor barrier configuration (where required)
+type: radio
+options:
+ - Bituminous sheet per ASTM E1993
+ - Multi-layer laminate certified to ≤ 0.01 perms
+default: Bituminous sheet per ASTM E1993
+```
+
+## Accessory Materials {toc}
+
+### Seam tape shall be the pressure-sensitive tape produced or approved by the membrane manufacturer for use with the specified membrane.
+
+### Field-improvised tapes are a leading cause of seam failure. Standard duct tape and generic packaging tape do not bond reliably to polyethylene and lose adhesion in the moist sub-slab environment. Only the manufacturer's project-specific seam tape carries a compatibility and performance warranty for the joint. {note}
+
+### Pipe boots and penetration collars shall be the prefabricated or field-formed components produced or approved by the membrane manufacturer for the specified membrane.
+
+### Mastic and sealant used to seal penetrations and terminations shall be compatible with the membrane and approved by the membrane manufacturer.
+
+### Repair patch material shall be the same membrane as the field sheet.
+
+# Sub-Base and Placement Position {toc}
+
+## The membrane shall be placed directly beneath the concrete slab, in contact with the underside of the slab, on a prepared sub-base.
+
+## ACI 302.1R explicitly recommends placing the vapor retarder directly under the slab. This is a deliberate reversal of the older "blotter" method and is the current position for moisture-sensitive applications. {note}
+
+## A granular blotter layer shall not be placed on top of the membrane beneath a slab that will receive moisture-sensitive flooring.
+
+## The legacy blotter detail placed several inches of sand or fine granular fill on top of the membrane, with the slab poured on the blotter. The intent was to absorb bleed water and reduce curling, but the blotter traps bleed water against the slab and stays saturated, which dramatically slows slab drying and keeps the relative humidity at the flooring level high for months. For any slab receiving moisture-sensitive flooring, the blotter is omitted and the slab is poured directly on the membrane. {note}
+
+## The sub-base supporting the membrane shall be a compacted, fine-graded surface free of sharp protrusions, ruts, and debris that could puncture the membrane.
+
+## Design and compaction of the granular sub-base are outside this scope and are covered by [[sync/slab-on-grade]] and [[sync/site-rough-grading]]; this Standard governs only the condition of that surface where it receives the membrane. Where a granular cushion is used to protect the membrane on a coarse sub-base, a minimum 4 in. of compacted granular material per ACI 302.1R is typical. {note}
+
+```datasheet
+label: Membrane placement position
+type: radio
+options:
+ - Directly under slab, no blotter (current ACI recommendation)
+ - Under slab with granular cushion below membrane on coarse sub-base
+default: Directly under slab, no blotter (current ACI recommendation)
+```
+
+# Installation {toc}
+
+## General {toc}
+
+### The membrane shall be installed in accordance with ASTM E1643 and the manufacturer's printed instructions.
+
+### The membrane shall be unrolled and positioned so the long dimension of the sheet runs in the direction that minimizes the number of end laps. {note}
+
+### The membrane shall be installed continuously over the entire slab area to be protected, with no gaps.
+
+### The membrane shall be drawn taut and free of wrinkles and fishmouths before concrete placement, to the extent practical without stretching the sheet beyond its rated elongation. {note}
+
+## Laps and Seams {toc}
+
+### Adjacent membrane sheets shall lap a minimum of 6 in. {note}
+
+### ASTM E1643 sets the minimum lap at 6 in. The lap is the most likely path for vapor to bypass the membrane, so the width is a floor, not a target; widen it where the manufacturer's detail or field conditions warrant. {note}
+
+```datasheet
+label: Minimum seam lap width
+type: range
+unit: in
+min: 6
+max: 12
+step: 1
+default: 6
+```
+
+### All laps shall be sealed with the manufacturer's seam tape for vapor barrier applications. {note}
+
+### Sealed (taped) laps are mandatory wherever the membrane functions as a vapor barrier or a Class A/B vapor retarder under moisture-sensitive flooring. Unsealed, unsupported laps are acceptable only for basic below-grade dampproofing, which is outside the moisture-sensitive scope this Standard is written for. {note}
+
+### Seam tape shall be applied to clean, dry membrane surfaces and pressed to achieve continuous adhesion across the full lap.
+
+### End laps and side laps shall be sealed by the same method.
+
+```datasheet
+label: Seam sealing method
+type: radio
+options:
+ - Manufacturer seam tape, fully sealed
+ - Manufacturer-supplied double-sided tape within lap
+default: Manufacturer seam tape, fully sealed
+```
+
+## Penetrations {toc}
+
+### Every pipe, conduit, drain, and other penetration through the membrane shall be sealed with a manufacturer-approved boot, collar, or mastic detail compatible with the membrane. {note}
+
+### Penetrations are the most common moisture ingress point in an otherwise sound installation. A continuous membrane with unsealed pipe penetrations is not a vapor barrier. Each penetration is sealed individually with a detail rated for the membrane type, not patched with field tape. {note}
+
+### Pipe penetrations shall be sealed with a prefabricated pipe boot where one is available for the penetration size, or with a field-formed collar sealed to both the pipe and the membrane.
+
+### The membrane shall be sealed tightly to the penetrating element so that no open annular gap remains.
+
+### Penetration locations and the routing of under-slab utilities shall be coordinated with the plumbing, electrical, and mechanical work as shown. [[drawing: under-slab utility penetration locations]]
+
+```datasheet
+label: Penetration sealing method
+type: radio
+options:
+ - Prefabricated pipe boot
+ - Field-formed collar with mastic
+ - Manufacturer pre-cut collar
+default: Prefabricated pipe boot
+```
+
+## Perimeter Termination {toc}
+
+### The membrane shall be terminated at the slab perimeter so that no continuous moisture path bypasses the membrane at the slab edge. {note}
+
+### An unsealed perimeter lets soil moisture migrate under the slab edge and around the membrane, defeating the field installation. The termination detail depends on whether the slab abuts a foundation wall, a grade beam, or a thickened edge, and on the below-grade wall dampproofing it must tie into. {note}
+
+### The membrane shall be lapped up and sealed to the foundation wall, grade beam, or footing face as shown.
+
+### Where the slab edge abuts below-grade wall dampproofing or waterproofing, the membrane termination shall be lapped and sealed to that assembly so the two systems are continuous. {note}
+
+### Failing to tie the under-slab membrane to the wall dampproofing is a common detailing gap; the two assemblies are coordinated so there is no break in moisture control at the wall-to-slab joint. {note}
+
+```datasheet
+label: Perimeter termination detail
+type: radio
+options:
+ - Lap up and seal to foundation wall
+ - Lap up and seal to grade beam
+ - Lap over and seal to footing face
+ - Seal to below-grade wall dampproofing
+default: Lap up and seal to foundation wall
+```
+
+## Repair {toc}
+
+### The membrane shall be inspected for damage immediately before concrete placement, and all tears, punctures, and open seams shall be repaired before concrete is placed. {note}
+
+### Form stakes, rebar chairs, and foot traffic routinely tear the membrane between installation and the pour. Specifying repair before placement is frequently omitted, and the omission is exactly why so many installed barriers underperform; once concrete covers the membrane, no defect can be corrected. {note}
+
+### Damaged areas shall be repaired with a patch of the same membrane, overlapping the damage a minimum of 6 in. in all directions, sealed per ASTM E1643.
+
+```datasheet
+label: Repair patch overlap beyond damage (each direction)
+type: range
+unit: in
+min: 6
+max: 12
+step: 1
+default: 6
+```
+
+## Exposure and Coordination with Concrete Placement {toc}
+
+### Concrete shall be placed over the membrane within the maximum exposure interval established at the pre-installation conference, after which the membrane shall be re-inspected and repaired before placement. {note}
+
+### Polyethylene degrades under sustained UV exposure, and wind and construction traffic accumulate damage over time. Fixing a maximum interval keeps the membrane in serviceable condition at the pour; if the schedule slips past it, the membrane is re-inspected rather than assumed sound. {note}
+
+```datasheet
+label: Maximum membrane exposure before concrete placement
+type: range
+unit: days
+min: 3
+max: 30
+step: 1
+default: 14
+```
+
+### Concrete placement shall not damage or displace the membrane; equipment, chutes, and personnel routing shall protect the installed sheet. {note}
+
+### Concrete mix design, placement, curing, and finishing are governed by [[sync/cast-in-place-concrete]]; this clause governs only protection of the membrane during the pour. Rebar chairs, support accessories, and other items bearing on the membrane are covered by [[sync/concrete-accessories]]. {note}
+
+## Radon Coordination {toc}
+
+### Where the project is in an EPA radon Zone 1 area or the Contract Documents require radon control, the membrane type and all penetration sealing shall be coordinated with the sub-slab depressurization system. {note}
+
+### In high-radon areas a vapor barrier alone may be insufficient; the membrane works with a sub-slab depressurization system, and the two are coordinated so penetrations are sealed and the barrier supports the mechanical mitigation. This coordination is with the mechanical work and is confirmed in the informational submittals. {note}
+
+### Penetrations serving the sub-slab depressurization system shall be sealed to the membrane to the same standard as all other penetrations.
+
+```datasheet
+label: Radon coordination required
+type: radio
+options:
+ - "Yes - coordinate with sub-slab depressurization system"
+ - "No - not in a designated radon control area"
+default: "No - not in a designated radon control area"
+```
+
+# Testing {toc}
+
+## Post-Cure Slab Moisture Verification {toc}
+
+### Before moisture-sensitive flooring is installed, the slab relative humidity shall be tested per ASTM F2170 using in situ probes. {note}
+
+### The under-slab membrane controls vapor from the soil, but the concrete itself releases mixing water as it cures. ASTM F2170 measures the in-place relative humidity inside the slab, which is the test flooring and adhesive manufacturers rely on to confirm the slab is dry enough to receive the finish. A correctly installed vapor barrier shortens the drying time and lets the slab reach the threshold; it does not eliminate the test. {note}
+
+### The slab relative humidity shall not exceed the threshold required by the flooring or adhesive manufacturer before flooring is installed. {note}
+
+### A relative humidity of 75% is a common ceiling for resilient flooring, but the controlling value is whatever the flooring or adhesive manufacturer states; some systems require 80% and some require lower. The more stringent of the manufacturer's value and 75% governs unless the manufacturer permits otherwise in writing. {note}
+
+```datasheet
+label: Maximum slab relative humidity before flooring (ASTM F2170)
+type: range
+unit: "%"
+min: 70
+max: 85
+step: 1
+default: 75
+```
+
+### Relative humidity testing shall not begin until the slab has cured and dried sufficiently for a representative result. {note}
+
+### A minimum drying period of approximately 60 days is typical for standard water-cement-ratio concrete before relative humidity testing is meaningful, but the actual time varies with the water-cement ratio, slab thickness, and the drying environment. The probes are read after the slab has had a realistic opportunity to dry, not on a fixed calendar date alone. {note}
+
+```datasheet
+label: Minimum slab drying period before RH testing
+type: range
+unit: days
+min: 30
+max: 90
+step: 5
+default: 60
+```
+
+### The number and distribution of test locations shall conform to ASTM F2170.
+
+# Delivery, Storage, and Handling {toc}
+
+## Membrane rolls, seam tape, boots, and mastic shall be delivered in the manufacturer's original packaging with labels intact and the product designation legible.
+
+## Membrane rolls shall be stored off the ground, protected from prolonged sunlight, and protected from puncture and crushing until installed. {note}
+
+## Polyethylene and bituminous sheet both degrade under sustained UV exposure, and crushed or punctured rolls yield damaged sheet that is hard to detect once unrolled. {note}
+
+## Seam tape and mastic shall be stored within the temperature range the manufacturer specifies so their adhesion is not compromised.
+
+## Damaged rolls and material past the manufacturer's shelf life shall not be installed.
+
+# Warranty {toc}
+
+## The membrane manufacturer shall warrant the membrane against defects in material for the period the manufacturer publishes for the specified product. {note}
+
+## The under-slab membrane is buried and permanent; it cannot be inspected or replaced over the life of the slab, so the manufacturer's material warranty and the certified test data at submittal are the only assurances of long-term performance. There is no field warranty for the installed assembly beyond the Contractor's workmanship obligations, because the assembly is concealed at completion. {note}
+
+## The Contractor shall warrant the membrane installation, including laps, penetration seals, and terminations, against defects in workmanship for the project's general construction warranty period.
+
+```datasheet
+label: Manufacturer material warranty period
+type: range
+unit: years
+min: 1
+max: 20
+step: 1
+default: 5
+```