The word “drainage” is a word you either hate or love. Excessive water around a house and garden is bad for everything — plants and home.
Poor drainage around a house is often the contractor’s failure to properly grade the structure once construction is finished.
Your lot should be graded to drain surface water away from foundation walls, according to Jamison Brown of Home Inspections by Jamison & Co. in Poquoson.
A good grade slopes a minimum of six inches within the first 10 feet; when that’s not possible, drains or swales can be constructed to get the job done.
“Faulty or reverse lot grade allows roof water run-off to flow back toward the home where it can wash out the soil around the foundation and lead to foundation failure, over the long term,” says Brown, who has been inspecting homes for 28 years.
“During the short term, water that gains access to the soil in the crawl space allows wood-destroying fungi to form. A wet crawl space can lead to distorted framing and flooring and creates an environment conducive to termite infestation.”
Sometimes, poor drainage is the result of too much clay, which is dense and holds water during heavy rains. Wet clay swells, and feels slick. During hot, dry weather, clay gets hard and shrinks — helping to cause a destructive condition called shrink-swell soil that can wreak havoc on foundations.
“I have seen a number of homes over the years with serious drainage problems that could have been averted had the builder raised the foundation by one or two rows of concrete block,” says Peggy Krapf of Heart’s Ease Landscape & Garden Design in the Williamsburg area.
“A simple and inexpensive fix at that stage — much more costly and complicated later.”
Crawl space woes
Ground water is the main cause of moisture-related problems in the crawl space, according to Kimberly Houston, president of Colonial Exterminating in Newport News.
“High moisture leads to fungal growth and damages,” she says. “It also invites many pests, including termites.
“And, 40 percent of the air in the crawl space is circulated into the house through the ‘chimney effect,’ which could bring hazardous fungus spores and insect debris with it.
“Some good options to improve drainage around your home include: install gutters and downspouts, keep gutters and downspouts clean of debris and grade soil away from your home’s foundation.”
Sometimes, a French drain is all that’s needed to get water into the ground where it can quickly dispense. I used this technique effectively, making only a huge, deep hole filled with rock, next to back steps where water puddled too much.
For a more complicated situation, I hired a specialty contractor to do an interior French drain under a foundation’s low crawl space. Water caught by the drains fed into a sump pump that emptied into another drain basin in the yard. In this situation, regular pump inspections insure the system keeps working.
I’ve also had exterior French drains done with pervious pipe, and eventually sediment filled the drains, making them worthless.
For a 3,000-square-foot, one-story house we just bought, Ken and I attacked a too-wet yard early on, knowing the expansive roof was dumping hundreds of gallons of water per one-inch rainfall. Each time heavy rains happened, the downspouts carried rivers of water onto soggy soil. Unbelievably so, for every one inch of rain that falls on a 1,000-square-foot roof, expect 600 gallons of water on your yard.
Steve Nassan of A-1 Lawn and Landscaping Services in Virginia Beach installed a Speedy Basin Drain System with a collection box located in the lowest area of the yard. It collects water and sends it underground by gravity to the street through a hole created in the curbing. PVC connectors on five of our six downspouts feed the water into four-inch flexible pipes with no holes in them. The pipes also lead to pop-up drains at the rear of the property, giving the water two directions to flow and empty quickly.
“More than 80 percent of my business is drainage systems,” says Nassan.
“Standing water around a house is bad for the foundation. It can cause the house to settle, compromising the foundation and possibly leading to cracks. Too much water around plants can cause roots to rot and kill plants.
“The Speed Basin Drain System takes care of all that.
“French drains work in the beginning but dirt, grass clippings, etc., start to get into the gravel, causing the water to slow down going into the pipe.”
In addition to downspouts, our AC drain line also feeds into the underground pipes. Central air-conditioning systems can easily collect 10 to 15 to 20 gallons of water daily, depending on the size of the house and system cooling it. Consider directing that water away from your foundation, at least to a gardening area where moisture-loving plants can drink it up.
Rain gardens & barrels
Water from gutter downspouts or an AC drain pipe also can be directed to planting areas called “rain gardens.” Simply put, a rain garden is a special spot that collects water for plants to drink. Usually, any clay or bad soil is excavated to a depth of about 30 inches. A shallow layer, or about six inches, of gravel is placed in the bottom. Fill the area with good, porous soil, install your moisture-loving plants and mulch generously.
Rain gardens can also be used to collect water from low-lying hard surfaces like driveways and walkways.
Rain barrels attached to downspouts are the easiest and most effective ways for catching rainwater from your roof. Water collected in those barrels can be used to water plants, wash off garden tools or moisten your compost pile.
Barrels with spigots can be purchased at local garden centers and hardware stores.
Build your own rain barrel with directions from AskHRgreen.org, a public awareness of 17 Hampton Roads city and county governments and the Hampton Roads Planning District Commission, at http://askhrgreen.org/how-to-build-a-rain-barrel.
Learn more about rain garden design and usage with AskHRgreen.org at http://askhrgreen.org/rain-gardens and the Hampton Roads Agricultural Research and Extension Center in Virginia Beach at arec.vaes.vt.edu/hampton-roads/gardens/rain-garden/index.html.
10 moisture-loving perennials
These plants are ideal for rain gardens and low-lying, moisture-rich spots:
•Dwarf swamp sunflower
•New England aster
•Virginia blue flag
5 moisture-loving shrubs
•Scarlet swamp hibiscus
3 moisture-loving trees
•White fringe tree
Even though all these plants are labeled as “moisture-lovers,” they do not like to sit in standing water. Organic compost or finely shredded hardwood mulch worked into the planting soil around them will help the area drain better.