Water, Water Everywhere

The last few days have been just fabulous weather – if you’re a duck. Or frog. Or gator. All of this rain has provided an excellent “opportunity” to evaluate the water runoff patterns around our homes. In many of the houses we inspect, outdoor water control (or lack of) has a significant impact on indoor moisture and air quality. It is definitely worth taking some time to make sure water runoff is not an issue for your foundation or crawlspace.

Any water that does not soak into the ground, whether it comes from a heavy rain or sprinkler runoff, has to go somewhere. Ideally, our houses are elevated so that water runs away from each and every wall. In the real world, it seems like this hardly ever happens.
Impervious surfaces such as roofs, walkways and patios repel every drop of rainwater that falls on them. A 1-inch rainfall on a typical 1,200 square foot roof generates almost 750 gallons of water. Since these surfaces are man-made, they are usually installed with at least some slope to drain the water, which means that gutters, pipes and drains can be added to catch runoff. Once this water is collected, it should be directed as far from your foundation as possible. Many people assume that the angled downspout at the base of the gutter pipe is sufficient to keep water away from the house, but this is hardly ever true. Splash blocks, extensions and flexible spouts are all important “accessories” for a complete and effective gutter system. Also remember that a clogged gutter is a useless gutter. Clean both the gutters and the full length of the downspouts to prevent backups.

Uncovered paving also generates runoff and can impact the foundation if not properly drained. Because we have little or no ground slope in this part of the world, moving that paving runoff can be a bit of challenge, but it is do-able. New installations can use continuous grates and piping to collect and direct water. Runoff from existing paving can be managed by adding a narrow french drain (gravel-filled trench) along the full length of the lowest edge of paving. The french drain should be sloped to lead away from the house into a discharge area such as a ditch or curb inlet. Please be mindful that moving water off of your property might wind up moving it into your neighbor’s yard. In the Gulf South, both good fences and good ditches make good neighbors.

Rain isn’t the only source of runoff water – landscape irrigation, especially when run on a regular basis – can contribute heavily to water issues. Foundation plantings in particular should be carefully sloped away from the house. Also, for raised houses, be sure that the foundation planting does not block a drainage pathway and cause pooling in the crawlspace. Using soaker hoses on timers instead of sprinklers reduces runoff, overall water use and your utility bill as well.

Finally, be sure that all service drain lines for the HVAC system and appliances extend well past the foundation and that their discharge does not form puddles.

On a larger scale, good drainage is just as important in subdivisions or rural neighborhoods. Improper drainage in these areas can impact lift stations, road access and mosquito populations. If you live in an area with subsurface drainage, watch the drain inlets and keep them free of yard debris and trash. Neighborhood associations should stay in regular contact with the parish to ensure regular cleaning and maintenance of stormwater pipes. If your neighborhood relies on a network of ditches for drainage, make sure that the area you are responsible for stays open and weed-free. Culverts (short lengths of piping under roads and driveways) must be in good condition to allow the maximum flow of water and the ditches themselves should be regularly dredged or dug by the parish to maintain proper slope.

This blog was written for Paul LaGrange’s BuildWrite website and was originally posted on September 11, 2009.


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