12.2.1.1 Solvent-Based Dampproofing Mastics
Solvent-based dampproofing mastic is composed of asphalt compounds containing various amounts of fibre reinforcement, depending upon whether the material is to be installed by spray, brush, or trowel.
Solvent-based dampproofing mastic is used to reduce water or moisture infiltration on foundation walls below grade where no hydrostatic pressure exists or on the interior side of masonry walls above grade.
Solvent-based dampproofing mastic should not be installed when ambient conditions are below 4.4°C (40ºF) unless specified by manufacturer. Because they remain somewhat sticky and are black in colour; these mastics, when used in interior applications, should be protected by furring and drywall or other finish.
Surface Preparation
Surfaces to receive solvent-based dampproofing mastic must be fully cured, broom clean, adequately dry, and free of oil, form release agents, curing compounds, grease, and loose materials.
Application
Apply solvent-based mastic by spray, brush, or trowel using a grade of product consistent with the method of application. Trowel applications should consist of one coat approximately 6 mm (1/4 in) thick. Spray or brush applications should consist of two coats approximately 1.6 mm (1/16 in) thick each, allowing material to dry between coats.
Protection Course
- For below-grade applications, cover the dampproofing coating with a protection board as recommended by the membrane manufacturer.
- Allow dampproofing to cure at least 24 hours to prevent displacement before applying protection board.
12.2.1.2 Bituminous Emulsion Dampproofing
Bituminous emulsion dampproofing materials are composed of water-soluble asphalt compounds containing various amounts of fibre reinforcement, depending upon whether the material is to be installed by spray, brush, or trowel. Unreinforced emulsions are also available.
Bituminous emulsion dampproofing materials are used to reduce water or moisture infiltration on foundation walls below grade where hydrostatic pressure relief systems have been employed, and on the interior side of masonry walls above grade.
Bituminous emulsion dampproofing materials should not be installed when ambient conditions are below 4.4°C (40ºF) unless specified by manufacturer. The completed application must be protected from water until it is fully cured.
Application
Apply solvent-based mastic by spray, brush, or trowel using a grade of product consistent with the method of application. Trowel applications should consist of one coat approximately 3 mm (1/8 in) thick. Spray or brush applications should consist of two coats approximately 1.6 mm (1/16 in) thick each, allowing material to dry between coats. Apply non-fibrated emulsion by spray, as per manufacturer’s specifications.
Protection Course
For below-grade applications, cover the dampproofing coating with a protection board as recommended by the membrane manufacturer. Allow dampproofing to cure at least 24 hours to prevent displacement before applying protection board.
Miscellaneous Materials
The following materials may be required to complement the installation of the waterproofing material.
Protection Courses
Protection courses are used to protect waterproofing membranes from damage during backfill operations and from installation of finished surfaces by other trades. Protection courses are generally installed on vertical surfaces immediately following the installation of the waterproofing material, and are held in place with adhesive. The four most common types of protection courses used are:
Bitumen-Bound Expanded Polystyrene Drainage Board
Bitumen-bound expanded polystyrene drainage boards are fabricated with large (3 mm to 12.7 mm (1/8 in to 1/2 in) diameter) polystyrene beads bound together with a bituminous adhesive, forming channels that allow water to freely pass through the board. The waterproofing adhesive helps protect the polystyrene beads from moisture, and therefore helps preserve the product’s insulating value. The product is available with a variety of factory laminated filter fabrics to handle the soil conditions at the specific site.
Bitumen-bound expanded polystyrene drainage boards are available in thicknesses from 25 mm to 600 mm (1 in to 24 in). The board is usually adhered to the waterproofing membrane with adhesive or stick clips.
Nylon Matting with Laminated Filter Fabric
Nylon matting geocomposites consist of three-dimensional, compression-resistant nylon matting, factory-laminated with a specific filter fabric. The product is available in thicknesses of 8 mm and 17 mm (1/3 in and 2/3 in), and is usually furnished in rolls that are attached to the substrate using stick clips. Some manufacturers recommend that a separate protection board be used between the waterproofing membrane and this material.
Plastic Drainage Core with Laminated Filter Fabric
This consists of waffle-like plastic core material factory-laminated with a specific filter fabric. The material is approximately 9.5 mm (3/8 in) thick, and is usually furnished in rolls that are attached to the substrate with stick clips. Some manufacturers recommend that a separate protection board be used between the waterproofing membrane and this geocomposite material.
Insulating Foundation Drainage Panels
Panels consist of high density, moisture-resistant insulation boards with grooved drainage channels on one face that are covered with a geotextile. Panels provide protection for waterproofing, thermal insulation, and drainage for ground water. Panels are held in place with adhesives or stick clips.