Waterproofing Foundations Below-Grade
- BASIC WATERPROOFING MEMBRANE OR WATERPROOFING MEMBRANE FOR FOUNDATIONS/ICF
- BLACK ELASTOMERIC SEALER
- EXTERIOR PRIMER OR H2O PRIMER
RESISTO membranes must be installed on a clean, dry surface. The minimum application temperature is 50 °F (10 °C). For cold weather application, RESISTO recommends the use of winter grade membranes that can be installed at a temperature up to 14 °F (-10 °C). It is also important to condition the membranes at a temperature of at least 50 °F (10 °C) before installation.
Use a chalk line to delineate the application surface of the membrane.
Mix the primer well before application.
Apply a coat of RESISTO PRIMER with a brush or roller on a clean, dry surface. The use of a primer may be necessary under certain conditions on surfaces made of insulated concrete formwork (ICF) (consult the product sheet for more details). Only the H2O PRIMER can be used on polystyrene surfaces prior to the installation of the membrane. On concrete or wood surfaces, RESISTO recommends the use of the EXTERIOR PRIMER.
NOTE: If a foundation coating has recently been applied to the walls, please contact a RESISTO representative: the RESISTO EXTERIOR PRIMER, which is solvent-based, can cause the coating to thin and reduce surface adhesion.
Prepare the installation of the membrane on the corners of the foundation. When a corner is to be covered with the RESISTO BASIC WATERPROOFING MEMBRANE, first apply a gusset (small piece of membrane to be cut) to ensure waterproofing.
For concrete or treated wood foundations only: Apply a bead (maximum 0.5 in [1.2 cm] in diameter) of RESISTO ELASTOMERIC SEALER in the joint between the footing and the foundation wall to ensure optimal waterproofing following the installation of the membrane on the transition zone.
Cut the membrane in half lengthwise so as to obtain two strips of the height of the foundation to be covered.
Cover the corners of the foundation by placing one of these membrane strips to reinforce the projecting or receding angle of the foundation. Adhere one side at a time to properly position the membrane.
Position yourself on a corner of the foundation to start installing the membrane, working from top to bottom.
On a 4 in (10 cm) surface, remove the protective film on the underside to adhere the top of the membrane to the substrate. This step allows the membrane to stand on itself against the foundation.
While removing the protective film, apply pressure to the membrane with a small rubber roller to increase adhesion.
Provide an overlap of 4 in (10 cm) between each membrane strip (a dotted line printed on the membrane indicates the location of the overlap).
At the bottom of the wall, the membrane must cover two thirds of the foundation footing. In the case of an application on an insulated concrete formwork (ICF) foundation, you can allow 6 in (15 cm) of membrane exceeding ground level to ensure that rainwater does not reach the insulation. In that case, the above-ground level finish cladding (plaster or asbestos cement panels) would overlap the top of the membrane. A reinforcement mechanically attached to the foundation is required if parging is to be applied on the membrane.
To complete concrete or wood foundation waterproofing, apply the RESISTO ELASTOMERIC SEALER on the top of the membrane around the foundation and on the footing to prevent water infiltration.
To complete insulated concrete formwork (ICF) foundation waterproofing, apply the RESISTO ELASTOMER SEALER all around the foundation, on the footing only. For complete polystyrene surface waterproofing, apply a polystyrene-compatible sealer such as ChemLink M-1.
When backfilling, if the soil is rocky, we strongly recommend using sand as backfill material or installing protective panels (polystyrene insulation boards such as SOPRA-XPS 30) around the foundation to avoid damaging the membrane. However, if the backfill is clay-like, it is mandatory to install a protective panel to ensure the integrity of the waterproofing system.
This Installation Guide refers to the minimum installation steps required for the RESISTO product mentioned above. Please note that additional steps may be necessary depending on the substrate. However, this procedure is subject to change. RESISTO reserves the right to modify the documents and procedures at any time. Under no circumstances will RESISTO be liable for installation defects. For more information, please contact your representative, RESISTO’s technical support team, or your construction professional.