Question from Katherine & Mike - Basement Flooding
June 12, 2014
"We want a basement in our beach house, but are worried about flooding! Is there a relatively inexpensive way to prevent it?"
Answer from Ross Sanders
Dear Mike and Katherine,
There are four main sources of water that we will need to consider: surface water from precipitation, ground water and domestic water from leaking pipes or fixtures, and high humidity levels. Preventing flooding is nearly impossible but with thoughtful design, one can minimize the potential damage.
A great first step is locating a properly graded site that falls away from your house. This lets gravity do the work in taking water away from your foundation, basement or crawlspace. The next step is to maintain your gutters and downspouts. If you can see a visible “splash zone” under your gutters, part of your system isn’t working properly and you will need to them cleaned. Additionally, check to see that your gutters slope towards the downspouts and be sure the downspouts themselves are allowing maximum flow. Some jurisdictions don’t want you returning rainwater into the storm sewer system, so you will need to ask your local building office about any relevant ordinances.
Foundation perimeter drains are another relatively inexpensive and excellent way of keeping water out of your home. If your house isn’t the highest point on your property, you may need a trench drain or buried “french drain” to gather surface water and divert it away from your foundation. The perimeter drain, usually made of 4” PVC pipe with lots of holes drilled along its top length for water gathering, can be buried under a gravel bed beneath your roof’s drip line and can typically tie into the storm system just like your downspout. Deeper foundation perimeter drains are typically more effective, but are harder to install on existing houses, as they require trenching down to the foundation wall’s footing. On new construction, however, these drains combine nicely with surface-applied foundation wall waterproofing or drainage mats, to gather and control ground and surface water.
The approaches listed here are an added cost during the construction of your home, but compared to the potential financial and emotional costs that come with even minor flood damage, they may be money well spent!
Stay tuned for my Monday video post where I will be discussing newer trends in protecting basements and crawlspaces.