Down the Drain
When New Orleanians think about drainage, usually catch basins, canals and pumps come to mind. But proper drainage can also be an issue within the confines of your fence lines.
This occurs to me every time I drive through Lakeview. As its recovery takes shape, the shells of little 1950s ranch houses huddle in the shadows of new residential palaces. These new additions are frequently built on mounds of trucked-in dirt. It makes me wonder where the water goes when it rains.
Drainage is also on my mind whenever we get a good downpour. Recent work to replace rotten eaves on my house has left me without gutters for the past couple of months. The rush of water off of the A-frame roof pools in a low spot on the side of the property. As a result, the tropical plants over there are a verdant jungle flowered with an embarrassment of red, pink and purple blossoms. But I can’t help pondering how that water eventually escapes.
Architect Kenneth Gowland, seen above, has experience in everything from major institutional projects to renovation jobs. His Faubourg Marigny firm, MetroStudio New Orleans, has been designing a number of new houses for rebuilding families, including several in Lakeview. Nowadays, homeowners are paying a lot more attention to drainage.
The No. 1 rule of residential property drainage: Send it to the street. “You’re not supposed to drain water on to a piece of neighboring property,” Gowland says.
That can be a real challenge, he says, in older New Orleans neighborhoods, where the homes fill out narrow lots. Water has few options for travel from the back of the lot to the front.
But it’s important to take steps to avoid ponding, which can be a problem beneath raised houses. With a raised house, it’s important to keep the underside clean and free of debris and to ensure that the midpoint is the highest, Gowland says. “You don’t want to have a little hidden lake underneath there.”
Homeowners typically solve this problem by pushing in sand. Gowland, however, has been designing raised houses that in some cases stand astride nonstructural slabs, angled to push the water outward.
There are several reasons why this is important. First: insects. Mosquitoes thrive in areas where there’s standing water. More frightening, however, is the fact that moisture invites termites.
Then there are structural issues. Water can undermine a foundation; rot wood; and erode piers, particularly those made of antique bricks. Gowland recently had to replace piers at his own house, a historic dwelling in Faubourg St. John. Piers, especially those around the perimeter of a house, tend to wear away from exposure to moisture. “They’ll just look like round clumps of stone eventually, after 100 years,” Gowland says.
Slab-on-grade homes face their own problems. Often, these are caused by homeowners who set up gardens against the exterior walls. “You’re just begging for water problems,” Gowland says. “And you’re giving termites a nice little underground railroad right to your house.”
Driveways and patios are another potential source of problems. Gowland says they should be sloped away from the house on a 3 percent gradient. “You don’t want to create any kind of condition where water runs toward the house,” he says.
In addition, he recommends taking advantage of subsurface drainage. One approach is to dig what is called a French drain around the perimeter of the house. This typically consists of laying in a cutaway PVC pipe, where the open side is placed upward and covered with fabric and gravel, then tied into the subsurface drainage.
Because much of the water that ends up around the house hits the roof first, well-installed gutters are critical. Gutter hangers should be no more than 18 inches apart and installed at a uniform slope to ensure a good water flow. There should be at least one downspout per 40 feet of gutter, and downspouts should connect into whatever subsurface drainage is available. If subsurface drainage is unavailable, the downspouts should be angled to direct water flow away from the foundation of the house. If necessary, you can buy flexible plastic extensions to more precisely further direct water flow.
Once installed, however, gutters need constant cleaning to survive for long and keep water flowing. Corroded, leaky gutters can cause more damage than they prevent. (For example, the rotting eaves on my house likely got that way because the gutters were clogged and deteriorating.)
Subsurface drains require occasional cleaning, as well. To determine whether your subsurface drains are clogged, you can listen to the flow of water through the downspout. Better yet, you can disconnect the downspout and try to fill the subsurface receptacle using a garden hose; if it overflows, you know you have a clog.
Ultimately, Gowland says: “When it rains, your property is going to get wet. But as much as possible you want to control water and get it away from your house.”