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Section R406 Foundation Waterproofing and Dampproofing
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R406.1 Concrete and Masonry Foundation Dampproofing
Except where required by Section R406.2 to be waterproofed, foundation walls that retain earth and enclose interior spaces and floors below grade shall be dampproofed from the finished grade to the higher of the top of the footing or 6 inches (152 mm) below the top of the basement floor. Masonry walls shall have not less than 3/8-inch (9.5 mm) Portland cement parging applied to the exterior of the wall. The parging shall be dampproofed in accordance with one of the following:
- Bituminous coating.
- Three pounds per square yard (1.63 kg/m2) of acrylic modified cement.
- One-eighth-inch (3.2 mm) coat of surface-bonding cement complying with ASTM C887.
- Any material permitted for waterproofing in Section R406.2.
- Other approved methods or materials.
Exception: Parging of unit masonry walls is not required where a material is approved for direct application to the masonry.
R406.2 Concrete and Masonry Foundation Waterproofing
In areas where a high water table or other severe soil-water conditions are known to exist, exterior foundation walls that retain earth and enclose interior spaces and floors below grade shall be waterproofed from the finished grade to the higher of the top of the footing or 6 inches (152 mm) below the top of the basement floor. Walls shall be waterproofed in accordance with one of the following:
- Two-ply hot-mopped felts.
- Fifty-five-pound (25 kg) roll roofing.
- Forty-mil (1 mm) polymer-modified asphalt.
- Sixty-mil (1.5 mm) flexible polymer cement.
- One-eighth-inch (3 mm) cement-based, fiber-reinforced, waterproof coating.
- Sixty-mil (1.5 mm) solvent-free liquid-applied synthetic rubber.
All joints in membrane waterproofing shall be lapped and sealed with an adhesive compatible with the membrane.
Exception: Organic-solvent-based products such as hydrocarbons, chlorinated hydrocarbons, ketones and esters shall not be used for ICF walls with expanded polystyrene form material. Use of plastic roofing cements, acrylic coatings, latex coatings, mortars and pargings to seal ICF walls is permitted. Cold-setting asphalt or hot asphalt shall conform to Type C of ASTM D449. Hot asphalt shall be applied at a temperature of less than 200°F (93°C).
R406.3 Dampproofing for Wood Foundations
R406.3.1 Panel Joint Sealed
Plywood panel joints in the foundation walls shall be sealed full length with a caulking compound capable of producing a moistureproof seal under the conditions of temperature and moisture content at which it will be applied and used.
R406.3.2 Below-Grade Moisture Barrier
A 6-mil-thick (0.15 mm) polyethylene film shall be applied over the below-grade portion of exterior foundation walls prior to backfilling. Joints in the polyethylene film shall be lapped 6 inches (152 mm) and sealed with adhesive. The top edge of the polyethylene film shall be bonded to the sheathing to form a seal. Film areas at grade level shall be protected from mechanical damage and exposure by a pressure-preservative treated lumber or plywood strip attached to the wall several inches above finished grade level and extending approximately 9 inches (229 mm) below grade. The joint between the strip and the wall shall be caulked full length prior to fastening the strip to the wall. Where approved, other coverings appropriate to the architectural treatment shall be permitted to be used. The polyethylene film shall extend down to the bottom of the wood footing plate but shall not overlap or extend into the gravel or crushed stone footing.
R406.3.3 Porous Fill
The space between the excavation and the foundation wall shall be backfilled with the same material used for footings, up to a height of 1 foot (305 mm) above the footing for well-drained sites, or one-half the total backfill height for poorly drained sites. The porous fill shall be covered with strips of 30-pound (13.6 kg) asphalt paper or 6-mil (0.15 mm) polyethylene to permit water seepage while avoiding infiltration of fine soils.
The remainder of the excavated area shall be backfilled with the same type of soil as was removed during the excavation.
R406.4 Precast Concrete Foundation System Dampproofing
Related Code Sections
Section R406 Foundations, Foundation Waterproofing and Dampproofing
Except where required by Section R406.2 to be waterproofed, foundation walls that retain earth and enclose interior spaces and floors below grade ...