TeraPROOF™ a below-grade waterproofing system from Siplast showing various layers.

Below-grade waterproofing solutions: TeraPROOF™

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Siplast below-grade waterproofing systems

Siplast is your single-source provider of high-performance systems for the full building enclosure. From roofing and waterproofing to walls and below-grade, you have a trusted partner on every side of the building—all covered by one manufacturer for consistency and convenience, and supported by Siplast specialists that provide design guidance. With you every step of the way.

TeraPROOF™ is our line of high-performance solutions for below-grade applications engineered to create a robust waterproofing solution for commercial buildings. TeraPROOF™ systems are for horizontal and vertical waterproofing applications and designed for use in below-grade pre-applied and post-applied waterproofing systems.

The application of TeraPROOF™ systems includes the use of liquid STP or SBS membranes, and accessories such as a protection course, drainage systems, and others, to complete installation.

Pre-applied

A 3D cross-section diagram showing the layers of a Siplast pre-applied below-grade waterproofing system.

System overview

TeraPROOF™ Pre-Applied V-SBS and H-SBS Membrane are modified-bitumen, heat-weldable membranes for waterproofing applications. Designed for use in below-grade waterproofing systems prior to the placement of concrete, they consist of polyester mat impregnated and coated with SBS-modified bitumen. The top is surfaced with fine mineral aggregate and the bottom surface is coated with an SBS-modified bitumen adhesive layer specifically formulated for torch-lap sealing applications with a polyolefin burn-off film.
A 3D cross-section diagram showing the vertical membrane of a Siplast pre-applied below-grade waterproofing system.

1. Vertical membrane

Siplast offers a versatile portfolio of vertical membrane options for below-grade applications. The TeraPROOF™ Pre-Applied V-SBS and H-SBS Membranes are modified-bitumen, heat-weldable sheets for use in systems installed before concrete is placed. The V-SBS is designed for vertical use and features a 180-gram polyester mat.
A 3D cross-section diagram showing the horizontal membrane of a Siplast pre-applied below-grade waterproofing system.

2. Horizontal membrane

Siplast offers two product options for horizontal membranes in below-grade applications. The TeraPROOF™ Pre-Applied H-SBS Membrane is a modified-bitumen, heat-weldable sheet designed for use in systems installed before concrete is placed. This membrane is used for horizontal applications and a detail reinforcement consists of a 250-gram polyester mat impregnated with SBS-modified bitumen.
A 3D cross-section diagram showing the torch-applied reinforcement of a Siplast pre-applied below-grade waterproofing system.

3. Torch-applied membrane

Siplast® TeraPROOF™ Pre-Applied H-SBS Membrane is a modified bitumen membrane for horizontal waterproofing applications. Designed for use in below-grade waterproofing systems prior to the placement of concrete, TeraPROOF Pre-Applied H-SBS consists of a 250-gram polyester mat impregnated and coated with a styrene-butadiene-styrene (SBS) modified bitumen. The top side is surfaced with fine mineral aggregate and the back surface is coated with an SBS modified bitumen adhesive layer specifically formulated for torch lap sealing applications with a polyolefin burn-off film bottom surface.
TeraPROOF™ Pre-applied H-SBS Membrane data sheet
A 3D cross-section diagram showing the detail flashing of a Siplast pre-applied below-grade waterproofing system.

4. Detail flashing

Siplast® TeraPROOF™ STP Liquid Membrane is a liquid-applied flexible membrane waterproofing using silane terminated polymer (STP) chemistry. TeraPROOF STP Liquid Membrane is a high-solids, that can be used in conjunction with Pro Fleece for reinforcement of the membrane or detail areas.
TeraPROOF™ STP Liquid Membrane data sheet
A 3D cross-section diagram showing the horizontal substrate protection of a Siplast pre-applied below-grade waterproofing system.

5. Horizontal substrate protection

For horizontal substrate protection, the TeraPROOF™ Protection CS1000 composite sheet can be used as a protection course. It is designed to shield the waterproofing membrane from punctures caused by compacted subgrade beneath pre-applied systems or from overburden elements in horizontal assemblies. Additionally, the TeraPROOF™ 10-11 Drainage Mat can be utilized to relieve hydrostatic pressure and ensure a continuous path for water discharge. This two-layer composite features a dimpled drainage core bonded to a geotextile, allowing water to pass while filtering out soil particles.
A 3D cross-section diagram showing the drainage and filter fabric of a Siplast pre-applied below-grade waterproofing system.

6. Drainage and filter fabric

A high-performance, two-layer drainage composite that ensures a continuous path for water discharge and relieves hydrostatic pressure buildup. It features a dimpled drainage core made of impact- and tear-resistant co-polymer polypropylene, fully bonded to a high-strength, needle-punched polypropylene geotextile, allowing water to pass freely while blocking soil particles to prevent clogging.
TeraPROOF™ 10-11 Drainage Mat data sheet

Post-applied

A 3D cross-section diagram showing the layers of a Siplast post-applied below-grade waterproofing system.

System overview

A liquid-applied, single-component, high-solids, flexible waterproofing membrane used as vertical and horizontal membrane applications in post-applied systems, such as concrete foundation walls, split slabs, inverted roof areas, planters, equipment wells, and other underground construction. It can also be used in detail applications of pre-applied system applications, and used in conjunction with Pro Fleece for reinforcement of the membrane or detail areas.
A 3D cross-section diagram showing the vertical membrane of a Siplast post-applied below-grade waterproofing system.

1. Vertical membrane

TeraPROOF™ STP Liquid Membrane is a liquid-applied flexible membrane waterproofing using silane terminated polymer (STP) chemistry. TeraPROOF STP Liquid Membrane is a high-solids, single-component used in post applied membrane applications for vertical and horizontal waterproofing such as concrete foundation walls, split slabs, inverted roof areas, planters, equipment wells, and other underground construction. TeraPROOF STP Liquid Membrane can be used in conjunction with Pro Fleece for reinforcement of the membrane or detail areas.
View TeraPROOF™ STP Liquid Membrane data sheet Pro Fleece
A 3D cross-section diagram showing the horizontal membrane of a Siplast post-applied below-grade waterproofing system.

2. Horizontal membrane

Siplast® TeraPROOF™ STP Liquid Membrane is a liquid-applied flexible membrane waterproofing using silane terminated polymer (STP) chemistry. TeraPROOF STP Liquid Membrane is a high-solids, single-component used in post applied membrane applications for vertical and horizontal waterproofing such as concrete foundation walls, split slabs, inverted roof areas, planters, equipment wells, and other underground construction. TeraPROOF STP Liquid Membrane can be used in conjunction with Pro Fleece for reinforcement of the membrane or detail areas.
View TeraPROOF™ STP Liquid Membrane data sheet Pro Fleece
A 3D cross-section diagram showing the detail flashing of a Siplast post-applied below-grade waterproofing system.

3. Detail flashing

Siplast® TeraPROOF™ STP Liquid Membrane is a liquid-applied flexible membrane waterproofing using silane terminated polymer (STP) chemistry. TeraPROOF STP Liquid Membrane is a high-solids, single-component that can be used in conjunction with Pro Fleece for reinforcement of the membrane or detail areas. PS-715 NS Elastomeric Sealant can also be used to treat joints and gaps in the substrate and interfaces.
View TeraPROOF™ STP Liquid Membrane data sheet Pro Fleece
A 3D cross-section diagram showing the backfill protection of a Siplast post-applied below-grade waterproofing system.

4. Backfill protection

For backfill protection the TeraPROOF™ Protection CS1000 composite sheet is a key component. This product acts as a protection course, shielding the waterproofing membrane from damage and punctures caused by backfill. Additionally, the TeraPROOF™ 10-11 Drainage Mat can be used to manage water. This two-layer composite relieves hydrostatic pressure and ensures a continuous path for water discharge by using a dimpled core and a geotextile.
A 3D cross-section diagram showing the drainage and filter fabric of a Siplast post-applied below-grade waterproofing system.

5. Drainage and filter fabric

A high-performance, two-layer drainage composite that ensures a continuous path for water discharge and relieves hydrostatic pressure buildup. It features a dimpled drainage core made of impact- and tear-resistant co-polymer polypropylene, fully bonded to a high-strength, needle-punched polypropylene geotextile, allowing water to pass freely while blocking soil particles to prevent clogging.
TeraPROOF™ 10-11 Drainage Mat data sheet

Benefits of Siplast’s effective below-grade waterproofing

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Comprehensive below-grade portfolio

Full portfolio of below-grade waterproofing offerings
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Vertical & horizontal waterproofing

Vertical and horizontal waterproofing for pre- and post-applied applications
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Design & technical support

Siplast design and technical support to assist you at all stages of the project
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Warranty coverage

Single-source warranty coverage provided from one manufacturer
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Siplast below-grade waterproofing system applications

Compare TeraPROOF™ product applications in the table below.

PRE-APPLIED SYSTEM

TeraPROOF™ Pre-Applied H-SBS

TeraPROOF™ Pre-Applied V-SBS

TeraPROOF™ STP Liquid

TeraPROOF™ Protection CS1000

TeraPROOF™ 10-11 Drainage Mat

Vertical membrane

 *

Horizontal membrane

 *

Torch-applied reinforcement

Detail flashing

Horizontal substrate protection

Horizontal substrate protection

POST APPLIED SYSTEM

Vertical membrane

Horizontal membrane

Detail flashing

Backfill protection

Drainage and filter fabric

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* See installation guidelines for specific applications and details for liquid membrane integration into pre-applied waterproofing systems

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Suitable applications

TeraPROOF™ systems are suitable for structures with below-grade levels that function as part of the building’s operations or infrastructure, and where protecting environmental/occupant health is essential. These below-ground level areas may include:

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Navigate complex transitions and connections with experienced guidance. Facing complicated system transitions? Confirm continuity across below-grade, wall, and roof systems while gaining insights into systems covering all sides of the building, continuous insulation, and connection details. Meet with one of our experts for a personalized review of your project by providing us with your contact information and scheduling a time that is convenient for you.
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Technical resources

TeraPROOF™ liquid-applied installer’s guide

View post-applied liquid installer’s guide

TeraPROOF™ SBS pre-applied installer’s guide

View pre-applied SBS installer’s guide

RISE blog

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Below-grade waterproofing system application.

Factors to Consider When Choosing Below-Grade Waterproofing Systems

View below-grade waterproofing article
Construction site for new building using pre-applied waterproofing membrane material from Siplast.

Different Types of Below-Grade Waterproofing Solutions

View types of below-grade article
Construction site for new building using pre-applied waterproofing membrane material from Siplast.

Is Pre-Applied Waterproofing Right for Your Project Needs?

View pre-applied waterproofing article

Frequently asked questions

Below-grade waterproofing is a waterproofing system that’s applied to below ground level structures to prevent water infiltration and protect the building’s structural integrity. There are two main types of below-grade waterproofing - positive-side waterproofing and blindside waterproofing. Positive-side waterproofing, also referred to as exterior-side waterproofing or post-applied waterproofing, is installed on the side of the substrate that’s directly exposed to water after construction. Blindside waterproofing, also called pre-applied waterproofing, is installed against adjacent lag piling or other earth-stabilizing structures before construction of the foundation wall, then bonds with the concrete as it sets.
Below-grade waterproofing is a critical step in the construction of any structure with a basement, underground parking, or other subterranean spaces, as it safeguards the building’s structural integrity and can help insure strong performance during the service life of the building, when installed properly. Below-grade waterproofing is essential for below-grade structures as it helps prevent water damage, mold and mildew growth, and structural deterioration caused by moisture infiltration.
Below-grade waterproofing works by creating a continuous, impermeable barrier around the parts of a structure that are in direct contact with the soil and groundwater. This barrier prevents moisture from penetrating the porous materials of the foundation. When the waterproofing membrane is applied to the exterior of the foundation (positive-side waterproofing), it acts as the first line of defense, preventing water from reaching the structural walls. This application is often done during new construction when the foundation is fully accessible. When blindside  application is used, the waterproofing membrane is applied to the earth-retention system before the concrete foundation is poured, and as the concrete is placed, it bonds to the pre-applied membrane, creating an integrated waterproof barrier.
Materials used in positive-side waterproofing can include liquid-applied membranes, such as Siplast TeraPROOF™ STP, prefabricated modified bitumen, elastomeric, or TPO sheets, and mineral-based systems such as bentonite clay or crystalline. Materials used in blind-side waterproofing are SBS membranes, such as Siplast TeraPROOF™ Pre-Applied H-SBS and V-SBS membranes, PVC or HDPE membranes, and bentonite sheets.

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