Waterproofing and Radon

In spite of some pretty wet weather we have been making progress on our east side home. The foundation was completed over the weekend. As noted in an earlier posting we used Reward insulated forms for the house. The garage and screen porch foundations were constructed using concrete blocks as they are not heated areas.

100_3119, cropped The exterior walls of the house foundation need to have waterproofing applied. There are several products available to do this, but we like using a self-adhering sheet membrane. Called Mel-Rol, it is an excellent product to keep water out of a foundation. We install it from the top of the foundation wall down and out over the footing. The membrane adheres to the foam wall and also to itself.

 

100_3120 We also take care to deal with any radon gas properly. This includes several items. The first thing we do is install additional drainage piping under the basement floor. These pipes, shown as white tubes in the picture, are flexible plastic piping with perforated slots. The pipe is covered with a filter fabric to keep any silt out of the pipe. The piping is set in 8” of free-draining gravel. This gravel is sized with no rocks smaller than ½” and no rocks larger than about 1-1/2”. The gravel allows radon to migrate through it and collect in the piping. The piping is connected to the perimeter drains around the interior of the foundation footing. On top of the gravel we will install 6 mill polyethylene sheeting to prevent any radon from migrating up through any cracks in the basement floor. Finally, we will eventually install a PVC pipe vent from the sump pit up and out through the roof. This will collect any radon and vent it into the atmosphere.

100_3121 Once the waterproofing membrane has been installed and inspected we set the basement window area and egress wells. When those are in place we backfill against the foundation. During the backfilling process we run a smooth drum compactor in the garage to ensure that the subsoils are fully compacted. We top off the compacted soils with several inches of sand. We hope to pour the garage concrete floor soon.