Basement Waterproofing
Basement waterproofing refers to techniques used to prevent water from entering the basement of a house or other building. Effective below ground waterproofing will include both drainage and sealers.
Waterproofing is needed anytime a structure is built at ground level or below ground. Waterproofing and drainage considerations are especially needed in cases where ground water is likely to build up in the soil and raise the water table. This higher water table causes hydrostatic pressure to be exerted underneath basement floors and against basement walls. Hydrostatic pressure forces water in through cracks in foundation walls, through openings caused by expansion and contraction of the footing-foundation wall joint and up through floor cracks. Hydrostatic pressure can cause major structural damage to foundation walls and is likely to contribute to mold, decay and other moisture related problems.
Methods
The three measures developed to prevent this problem differ greatly in ideology and design. The first being interior wall and floor sealers. The other two methods are interior water drainage and exterior drainage combined with waterproofing coatings.Interior Sealants
Interior sealers will not provide permanent protection from water infiltration where hydrostatic pressure is present. Interior sealers are good for preventing high atmospheric humidity inside the basement, from absorbing into the porous masonry and to prevent spalling. Spalling is a condition where constant high humidity or moisture break down masonry surfaces causing deterioration and shedding of the concrete surfaces.Interior water drainage
Although interior water drainage is not technically waterproofing, it is a widely accepted technique in mitigating basement water and is generally referred to as a basement waterproofing solution. Many interior drainage systems are patented as well as recognized by B.O.C.A (Building Officials and Code Administrators)as being effective in controlling basement water. They function by draining underground water from alongside the foundation footers and underneath the basement floor. They then channel it with a French drain, PVC pipe, or through a patented product to a sump pump system, which will then pump the water from the basement. Foundation sump pumps can be installed through do-it-yourself kits, plumber installations, or by a professional waterproofing contractor and generally come in plastic and cast-iron models.To simplify:
- Water enters the home via the basement wall/floor joint, through cracks in the foundation walls and/or holes created by faulty or decaying masonry/brick.
- A perimeter trench drain such as a French drain collects the water before it enters into the basement.
- Wall vapor barriers/retarders and drip moldings are used and incorporated into the sub-slab perimeter drain to collect water coming from wall cracks and other foundation wall defects, such as pipe protrusions.
- The drain directs the water to a sump pump.
- The sump pump directs the water out of the house.
