From the Architect's Desk
On 26, Mar 2018 | In From the Architect's Desk | By lthomas
Spring rains do not necessarily equal wet basements!
As we move into spring, along with lovely blooms and breezes come what many homeowners fear—wet basements.
I personally live in an old home with a basement that many in my neighborhood with a similar arrangement refer to as a “cellar” because they have not been able to control the dampness, not to mention the occasional incoming water from heavy rains. As an architect, I am frequently asked if there is anything to be done about soggy or musty basements either before a home purchase or after years of frustration.
The best way to deal with this problem is in three distinct steps and areas of work:
Prevention involves keeping water away and out of your basement from the get-go. With new construction, this is fairly straightforward as nowadays this is standard construction practice. Drains are placed to both the interior and exterior of basement wall foundations and the walls are then waterproofed prior to the foundation being backfilled. Once the work is complete, the soil should be compacted and graded away from the foundation so that surface rain runs away from the house. Downspouts and gutters should drain away from the foundation, too. The idea here is to move water away from the basement so it never intrudes from the start.
In existing homes, particularly ones with old masonry walls, prevention can be a bit more problematic. The waterproofing may have been inadequate or nonexistent. In this case the best preventions are unclogging your drains and downspouts and verifying that any roof water runs away from the foundation edge. Sometimes interior waterproofing wall treatments can work, but with enough hydrostatic pressure, even the best interior wall treatments sometimes can fail in spots. Remember that the first line of defense is to keep water away!
Once water is seeping in, either through walls or the concrete slab, it is time for Diversion. This involves moving the problematic water away from interior surfaces. Foundation drains are typically installed in newer construction to move the water that is building up along the exterior face of your basement wall away to either a storm water system or to daylight drains in your yard. In older construction with mature exterior landscape it is often easier to install an interior perimeter drain, often referred to as a French Drain. A French Drain consists of a trench cut into the concrete floor adjacent to the walls that is filled with gravel and a perforated pipe. Any water that makes its way through the wall runs to the drain and is then led to out by gravity. New wall finishes cover this area. This system works well for homes built into a hill, for example, where water can easily drain to a low point on your property.
Alas, many homes cannot drain the basement level water to daylight. Hence we come to Relief. A sump pump/pit is designed to provide mechanical Relief to move water from the French Drain or relieve hydrostatic pressure below the slab and take it away from the home. A sump pump is a submersible pump that is located at the lowest point in the basement, below the concrete slab, and set in a small, perforated basin with gravel. The pit collects drain and ground water and the pump disperses it away from the home. With this system, it is critical to remember a battery or other back-up generator as the pump is electrical and will do you no good if your electricity fails in the midst of a heavy rain event.