Underseal® Underslab Membrane
U.S. Patent No. 7,488,523
U.S. Patent No. 7,686,903
Underseal® Underslab Membrane is a tough, 85-mil pre-concrete pour waterproofing membrane/vapor barrier designed to virtually eliminate water and vapor transmission through concrete slabs on grade. In addition to protecting floor finishes and indoor air quality, Underseal® Underslab Membrane also acts as a barrier to methane and radon gas.
Underseal® Underslab Membrane provides a continuous seal underneath the foundation slab. A strong mechanical bond is developed between the membrane and concrete at the time of pouring as the concrete intermingles with the fibers of the nonwoven geotextile. Underseal® Underslab Membrane is typically installed horizontally over a prepared subbase such as compacted soil, mud slab or #57 stone. 85 mil Underseal® Underslab can also be used in vertical applications.
FEATURES & BENEFITS
- Superior Protection: 3-layer composite membrane
- Superior Puncture Resistance: Higher than current Class A Vapor Barrier requirements (2200 grams, or under 5 pounds)
- Superior Resistance to Water Migration: Eliminates water and vapor migration by forming a strong mechanical bond to the concrete
- Superior Adhesive Bond: Creates a strong adhesive bond when the static load and thermal reactive heat of the concrete slab causes sealant/adhesive compound to have an intimate contact with the concrete surface
- Superior Adaptability: Flexible material that adapts to job site irregularities for ease of installation
- Superior Joints: Fully-adhering, watertight laps
- Superior Crack Protection: Stress-absorbing and elongation properties to maintain a watertight seal to the structure if cracks develop in the base material or the slab
- Superior Barrier: Acts as a barrier against toxic contaminants methane and radon gas, which may attempt to enter the structure through cracks in the concrete
Photo Gallery
Product Resources
Corners
File | Action |
---|---|
PGArch Detail US11 Underslab US Inside Corner Detail 07052018 | Download |
PGArch Detail US17 Underslab Preformed US Outside Corner Boot At Concrete Column 01182018 | Download |
PGArch Detail US21 Underslab Pit Top Corner Boot 10012014 | Download |
PGArch Detail US22 Underslab 650 Membrane Boot For Underslab Inside Corner 06052018 | Download |
PGArch Detail US23 Underslab Outside Corner Field Cut 07032019 | Download |
PGArch Detail US24 Underslab Field Made Outside Corner Boot 07032019 | Download |
Other
Penetrations
Repairs / Patches
Seams / Laps
Terminations
File | Action |
---|---|
PGArch Detail US3 Underslab Pile Termination Profile 1 03182014 | Download |
PGArch Detail US4 Underslab Pile Termination Profile 2 03182014 | Download |
PGArch Detail US5 Underslab Termination To Existing Concrete Wall 03182014 | Download |
PGArch Detail US7 Underslab Post Concrete Pour Termination Of Underslab To Face Of Footer Structural Slab 03182014 | Download |
Transitions
File | Action |
---|---|
PGArch Detail US1 Underslab Tie In To Blindside 11152019 | Download |
PGArch Detail US8 Underslab 650 Membrane Tie In To Post Terminated Underslab Profile1 03182014 | Download |
PGArch Detail US9 Underslab 650 or PRM Membrane Tie In To Embedded Underslab Profile 2 03182014 | Download |
PGArch Detail US14 Underslab 650 or PRM Membrane Tie In To Embedded Underslab Showing Polyflow 15 or 15P 03182014 | Download |
To obtain a DWG detail, you must:
Right click on button & select
Corners
File | Action |
---|---|
PGArch Detail US11 Underslab US Inside Corner Detail 07052018 | Download |
PGArch Detail US17 Underslab Preformed US Outside CornerBoot Concrete Column 01182018 | Download |
PGArch Detail US21 Underslab Pit Top Corner Boot 10012014 | Download |
PGArch Detail US22 Underslab 650 Membrane Boot For Underslab Inside Corner 06052018 | Download |
PGArch Detail US23 Underslab Outside Corner Field Cut 07032019 | Download |
PGArch Detail US24 Underslab Field Made Outside Corner Boot 07032019 | Download |
Other
Penetrations
Repairs / Patches
Seams / Laps
Terminations
File | Action |
---|---|
PGArch Detail US3 Underslab Pile Termination Profile1 03182014 | Download |
PGArch Detail US4 Underslab Pile Termination Profile2 03182014 | Download |
PGArch Detail US5 Underslab Termination To Existing Concrete Wall 03182014 | Download |
PGArch Detail US7 Underslab Post Concrete Pour Termination Of Underslab To Face Of Footer Structural Slab 03182014 | Download |
Transitions
File | Action |
---|---|
PGArch Detail US1 Underslab Tie In To Blindside 11152019 | Download |
PGArch Detail US8 Underslab 650 Membrane TieIn To Post Terminated Underslab Profile1 03182014 | Download |
PGArch Detail US9 Underslab 650 or PRM membrane TieIn To Embedded Underslab Profile2 03182014 | Download |
PGArch Detail US14 Underslab 650 or PRM membrane TieIn To Embedded Underslab Showing Polyflow 15or15P 03182014 | Download |
Product Submittals
For a job-specific submittal package, please contact Polyguard for Product Submittal Requests. Click here to find your area’s field representative.
Companion Products
(Where Applicable)
606 Tape | High strength double-sided tape comprised of rubberized asphalt. |
650 LT Liquid Adhesive | Used to prime all structural concrete, masonry, or wood surfaces prior to membrane installation. |
California Sealant | Used to seal all porous portions of Underseal® geotextile surface and promote adhesion of Polyguard sealants. |
Detail Sealant PW™ | VOC/HAPS-free high-performance solvent-free sealant. |
Detail Tape | Use as detail strips on corners, penetrations, joints, and for patching damaged areas of the membrane. |
LM-85 SSL | Self-leveling flood coat waterproofing membrane. |
LM-95 | Two-component fast cure urethane waterproofing membrane. |
Polyflow® 15 / 15P | Sheet molded drain for vertical application with a compressive strength of 15,000 psf. |
Polyflow® 18 | Sheet molded drain for horizontal application with a compressive strength of 21,000 psf. |
Underseal® Fabric Tape | Use around pipe penetrations and at end laps for patching damaged areas of the membrane. |
Underseal® Inside Corner Boot | To be applied in the inside corner to reinforce and seal the corners of the Underseal® Underslab membrane. |
Underseal® Outside Corner Boot | To be used in the outside corner to reinforce and seal the corner. |
Underseal® Pit Top Corner Boot | Preformed corner boot used to reinforce and seal the Underseal® Underslab Membrane and Underseal® Blindside™ Membrane. |

Underseal® Underslab Membrane
U.S. Patent No. 7,488,523
U.S. Patent No. 7,686,903
Underseal® Underslab Membrane is a tough, 85 mil pre-concrete pour waterproofing membrane/vapor barrier designed to virtually eliminate water and vapor transmission through concrete slabs on grade. In addition to protecting floor finishes and indoor air quality, Underseal® Underslab Membrane also acts as a barrier to methane and radon gas.
Underseal® Underslab Membrane provides a continuous seal underneath the foundation slab. A strong mechanical bond is developed between the membrane and concrete at time of pouring as the concrete intermingles with the fibers of the nonwoven geotextile. Underseal® Underslab Membrane is typically installed horizontally over a prepared sub base such as compacted soil, mud slab or #57 stone. 85 mil Underseal® Underslab can also be used in vertical applications.
FEATURES & BENEFITS
- Superior Protection: 3 layers of waterproofing protection
- Superior Puncture Resistance: Higher than current Class A Vapor Barrier requirements (2200 grams, or under 5 pounds)
- Superior Resistance to Water Migration: Eliminates water and vapor migration by forming a strong mechanical bond to the concrete
- Superior Adhesive Bond: Creates a strong adhesive bond when the static load and thermal reactive heat of the concrete slab causes sealant/adhesive compound to have an intimate contact with the concrete surface
- Superior Adaptability: Flexible material that adapts to jobsite irregularities for ease of installation
- Superior Joints: Fully-adhering, watertight laps
- Superior Crack Protection: Stress-absorbing and elongation properties to maintain a watertight seal to the structure if cracks develop in the base material or the slab
- Superior Barrier: Acts as a barrier against toxic contaminants, including methane and radon gas, which may attempt to enter the structure through cracks in the concrete
- Available in a Winter Formulation October through March
Photo Gallery
Companion Products
606 Tape | High strength double-sided tape comprised of rubberized asphalt | More Detail |
650 LT Liquid Adhesive | Used to prime all structural concrete, masonry, insulation or wood surfaces prior to membrane installation. | More Detail |
California Sealant | Used to prime structural surfaces on which waterproofing membranes will be applied | More Detail |
Detail Sealant PW™ | VOC./HAPS free high performance solvent-free sealant | More Detail |
LM-85 SSL | Self leveling flood coat waterproofing membrane | More Detail |