Combating Leaks and Wet Basements
Water – the substance that is so precious to life, the stuff that keeps our grass green, our dishes clean and our toilets flushing – is one of the biggest threats to the home.
Most people at one time or another have experienced damage to their home from water. A leaking roof, rotted siding, fungus-covered floor framing and a wet basement are a few examples of how water can harm a home. Even what might seem the least significant of leaks can cause major damage. For example, a pin- hole leak in a piece of roof flashing can soak attic insulation causing the ceiling to stain and sag. The water-soaked insulation can also cause surrounding wood framing to rot by means of capillary action. Or the waterlogged insulation can condense, allowing water vapor to attack other parts of the attic.
This scenario can be played out in virtually every area of the home where water is a threat. An area that is most susceptible to leaks and water damage is the basement. It doesn’t take a physicist to figure out why this is the case. A basement is, by design, embedded into the earth. As such, it is a magnet for any water that might be present around the home such as that produced by rain or irrigation.
In addition to the rot discussed earlier, a wet basement can cause the foundation to heave, resulting in cracks over windows and doors and out-of-level floors. This can happen even if your home doesn’t have a basement. A wet crawlspace or water under a concrete slab can be equally threatening.
The best defense against a wet basement, whether crawlspace or foundation, is a strong offense – water control. Water control – also referred to as watershed or drainage – is no one-trick pony. There are several elements to a well-integrated and effective system.
Before grabbing your pick and shovel and heading out to the back forty to install a French drain – which, by the way, you might ultimately need – we suggest that you begin conquering your water problem by tackling a few less-intimidating tasks.
If you don’t have rain gutters at the edge of your roof, install them. If you do, make sure that they are in good condition, and clean them periodically to ensure that they are doing a good job.
The same goes for downspouts. Repair or replace rusted, dented or damaged downspouts and, as with gutters, be sure that they are clean. Use a garden hose with a spray nozzle and a small plumber’s snake to clear any blockage, and flush debris out of the downspouts.
Consider installing gutter and/or downspout screens if you have lots of trees that overhang your roof.
A downspout never should be allowed to terminate at the base of the foundation. At a minimum, a precast plastic or concrete diverter (“splashblock”) should be installed immediately below the downspout to divert water away from the foundation. Alternative methods include drainage pipe laid on the ground which will carry water at least 20 feet away from the home. The best alternative is to install drainpipe below ground that will carry all downspout-generated water to a municipal storm drain or other central-collection system.
The dirt (or concrete) surrounding your home should be graded AWAY from the foundation. A good rule is at least a quarter of an inch per foot. When regrading soil to achieve this slope, be sure to recompact the soil, otherwise it will erode with the first rain.
If you have a window well for a window in your basement, be sure that it is well sealed. Consider installing gravel surrounding the well to permit good drainage.
Ventilation is key to controlling moisture and musty odors in a basement or crawlspace. Overgrown shrubs surrounding the house can keep ventilation ports from doing their job. Thus, all trees and shrubs surrounding the house should be regularly thinned.
Cracks in concrete foundations should be patched or caulked. Deteriorating mortar in brick or block foundations should be tuckpointed.
Consider installing a drainage sump with a pump that will eject water to the exterior. If your basement is still wet after following our advice, we suggest that you enlist the services of a geotechnical or “soils” engineer. He or she is best able to assess the conditions causing the problem and make specific recommendations that will dry out your basement or crawlspace once and for all.