Tempo:
Install water-resistant rigid insulation around the perimeter of the slab and protect it from physical or ultraviolet damage with parging or a board finish. To resist cracking, reinforce the slab with 9.5 mm (3⁄8 in.) thick steel reinforcing bars spaced 600 mm (24 in.) on centre in both directions. (The steel bars have a metric product designation of 10M.) Alternatively, welded wire mesh can be used that forms a grid of 152 mm (6 in.) squares in which the thickness of the steel is 3.4 mm (0.15 in.). [The metric product designation of this grid is 152 × 152 mm (MW 9.1 × 9.1.)] A mechanical float finish provides a smooth finished surface. The requirements for footings and foundations for houses with slabs-on-ground are similar to those for crawl spaces and constructed in the same manner. A structural slab, which supports loads from vehicles or the walls above, must be designed by an engineer.
FOUNDATION DAMPPROOFING Dampproofing is necessary for all foundations that contain habitable space to restrict the movement of soil moisture into the wall. Dampproofing materials include bitumen, polyethylene or other sheet material. In poorly-drained soils or soils with a high water table, waterproofing will be required. Dampproof concrete and unit masonry walls below grade with a heavy coat of bituminous material applied on the exterior surface from the footings to the finished grade line. Such a coating is usually sufficient to make the wall resistant to surface water moving down to the footing drainage system. Mineral fibre insulation or drainage layers are recommended to drain water away from the foundation walls.
Insulating concrete form (ICF) foundations must also be dampproofed and the material used must be compatible with the foam formwork/insulation. When backfilling walls, avoid causing damage to the dampproofing, waterproofing, insulation or drainage layer. Dampproofing is also required on the interior of concrete or unit masonry walls that come into contact with interior wood framing supporting insulation or interior finishes. When installed between the foundation wall and interior framing, the dampproofing prevents moisture in the foundation wall from coming into contact with the wood framing. It usually consists of building paper applied on the inside of the wall, and must extend from the basement floor and terminate at the exterior finish grade level.
WATERPROOFING Waterproofing is needed where there is a likelihood of hydrostatic water pressure and requires the services of a qualified professional to identify which measures are to be taken to deal with the water and the forces imposed on the foundation. Waterproofed foundations need not be dampproofed. For walls, waterproofing consists of an impermeable membrane, such as two layers of bitumen-saturated felt. The layers of felt are attached to the wall and each other and covered with liquid bitumen. Waterproofing materials for ICF foundations must be compatible with the foam formwork/insulation. Floor slabs must also be waterproofed where hydrostatic pressure could be an issue. The waterproofing materials must consist of a membrane sandwiched between two layers of concrete, each layer not less than 75 mm (3 in.) thick. The floor membrane must be sealed to the wall membrane. In many cases,
FOUNDATION DAMPPROOFING Dampproofing is necessary for all foundations that contain habitable space to restrict the movement of soil moisture into the wall. Dampproofing materials include bitumen, polyethylene or other sheet material. In poorly-drained soils or soils with a high water table, waterproofing will be required. Dampproof concrete and unit masonry walls below grade with a heavy coat of bituminous material applied on the exterior surface from the footings to the finished grade line. Such a coating is usually sufficient to make the wall resistant to surface water moving down to the footing drainage system. Mineral fibre insulation or drainage layers are recommended to drain water away from the foundation walls.
Insulating concrete form (ICF) foundations must also be dampproofed and the material used must be compatible with the foam formwork/insulation. When backfilling walls, avoid causing damage to the dampproofing, waterproofing, insulation or drainage layer. Dampproofing is also required on the interior of concrete or unit masonry walls that come into contact with interior wood framing supporting insulation or interior finishes. When installed between the foundation wall and interior framing, the dampproofing prevents moisture in the foundation wall from coming into contact with the wood framing. It usually consists of building paper applied on the inside of the wall, and must extend from the basement floor and terminate at the exterior finish grade level.
WATERPROOFING Waterproofing is needed where there is a likelihood of hydrostatic water pressure and requires the services of a qualified professional to identify which measures are to be taken to deal with the water and the forces imposed on the foundation. Waterproofed foundations need not be dampproofed. For walls, waterproofing consists of an impermeable membrane, such as two layers of bitumen-saturated felt. The layers of felt are attached to the wall and each other and covered with liquid bitumen. Waterproofing materials for ICF foundations must be compatible with the foam formwork/insulation. Floor slabs must also be waterproofed where hydrostatic pressure could be an issue. The waterproofing materials must consist of a membrane sandwiched between two layers of concrete, each layer not less than 75 mm (3 in.) thick. The floor membrane must be sealed to the wall membrane. In many cases,
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