Waterproofing the Basement Correctly
Waterproofing the Basement
Waterproofing the basement should begin during the construction process if possible. During the first phase of new construction when the footings and basement walls are first poured is the best time to head off future possible problems.
Begin the process of waterproofing the basement by correctly installing an approved drainage tile system around the perimeter of the footings. We recommend using a product like CertainTeed Form-a-Drain since this product serves as both a permanent footing form as well as an interior and exterior tiling system. This system when completed with recommended ventilation will also handle required Radon mitigation.
The next step in the process of waterproofing the basement is to thoroughly coat all exterior wall surfaces that will be below grade with a black tar based foundation coating or an acrylic based product. Once this product has dried it is time to back fill with washed gravel to cover the entire drainage tile and protect it from dirt infill that could eventually clog the drainage tile.
A last step that should be considered at this point is to plan for in ground drainage tile to conduct gutter downspout water runoff away from the basement walls. This tiling is often overlooked until late in the landscaping part of the project but with a little planning of the downspout locations it is much easier to install before all of the dirt back fill is put back up against the foundation.
Waterproofing the Basement of an Existing Home
If you are seeing signs of water concern in your existing basement the first thing to do is determine if what you are seeing is seepage from outside or condensation from inside. You also need to establish if the moisture occurs on the floor or the wall. To determine if the moisture is coming through the concrete surface or is condensation, begin by securely taping a sheet of plastic film one foot by one foot along all four edges over the area in question. Wait at least 24 hours before removing the plastic.
If you find moisture droplets on the surface under the plastic it’s a pretty good indication of moisture coming through the concrete. Another way to confirm this is if you see a white chalky material in certain places on the wall as this is a sign if effervescence or minerals drying from moisture coming through the wall.
If you confirm that moisture is coming through the wall there are two steps to the waterproofing the basement. First you will need hydraulic cement if there are any visible cracks larger than 1/8” wide. Hydraulic cement will expand and lock itself into the crack as it dries. Follow the manufactures instructions during this installation.
The next step is to paint the wall surface with a waterproofing paint. What makes waterproofing paint unique is the Portland cement that is a part of this paint. The Portland cement will fill the pinhole sized pores in the concrete. This is what seals the wall surface.
If you are sealing a basement floor then you will need to use an epoxy floor finish as this will give you the durability you need to be able to walk on the floor.