Got grade? Heavy rains in the past probably settled the question of whether the slope of the soil around your house is adequate. If you noticed water...
Got grade? Heavy rains in the past probably settled the question of whether the slope of the soil around your house is adequate. If you noticed water pooling in low-lying areas near your foundation, now is the time to fix the problem.
Water that moves toward the foundation instead of away from it can cause all kinds of problems, from a wet basement to an overworked sump pump that runs for days after a heavy rain. Over time, hydrostatic pressure (from water) can push in the foundation wall.
The goal of grading is simple: Create a slope that will carry water away from your house.
The slope doesn’t need to be as steep as you might think. A drop of 1 inch per foot for 6 feet is a good guideline, says structural engineer William Carter of Foundation Engineering Specialists in Kansas City.
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In other words, if you’re standing 6 feet away from your home, the soil should rise evenly to a point on the foundation that’s 6 inches higher than the ground you’re standing on. If you can spread the 6-inch rise over 12 feet, that’s even better, because it puts the water farther out into the yard. But you shouldn’t build up the level of soil at the foundation much more than 6 inches, even if you go out 12 feet. That’s because soil touching the exterior cladding of your home can promote trapped moisture or invite termites.
To create a proper grade, use a long board. Have someone help you hold one end against the foundation.
Using a ruler to measure, position the other end of the board 6 inches from soil level at the point where the slope will end. Set a level on top to make sure the board is straight. That shows how high the soil needs to go on the foundation.
The best way to tamp down the pulverized topsoil (regular topsoil is too difficult to spread into place) is to add 2 inches of rise at a time and walk it down with your feet. Then add 2 more inches and repeat until you are finished.
Source: David Frey, co-owner Kansas City Master Cos.
The good news is, upgrading your grade is simple and cheap, if you are willing to do the hard labor yourself. Pulverized topsoil costs about $25 per cubic yard if you buy it in bulk and pick it up yourself. One cubic yard is about as much as 14 40-pound bags from the garden center.
If you need to have the soil delivered, it will cost you more.
“You don’t need an engineer or heavy equipment,” said Jameon Schwarz of Pro Foundation Technology. “You can do it the old-fashioned way of one man and a wheelbarrow.”
If you don’t want to tax your back, plan on spending at least $500 to $600 to hire someone to build up the grading along a small section of your foundation. Poor grading usually is an isolated problem on a single side or corner of a house. For more extensive grading work, the cost could go up to $1,500 to $2,000, including the soil.
Several types of companies offer grading services. The cheapest are topsoil companies. (Look in telephone directories under “topsoil.”)
To determine how much topsoil it will take to improve the grading around your house:
• Start with the desired rise of slope.
• Multiply by extent of slope.
• Divide by 2.
• Multiply by the length of slope.
So, for a 6-inch rise, extending 12 feet from the home and running for 20 feet, you’d multiply 6 inches (.5 feet) by 12 (equals 6), divide by 2 (giving you 3) and multiply by 20 (for a total of 60 cubic feet).
Because topsoil is sold by the cubic yard, you’d have to convert by dividing by 27. (Using the example of 60 cubic feet, that would equal 2.22 cubic yards.)
And because pulverized topsoil is full of air, it will settle. To compensate, get a little more. Good rule of thumb here is to multiply your cubic-yard estimate by 1.2. (Using the example of 2.22 cubic yards, you would need 2.66 cubic yards for your project.)
Source: David Frey, co-owner Kansas City Master Cos. in Grandview, Mo.
Landscaping companies can do the work, too, but they will be pricier than companies that specialize in moving dirt. You might want to pay the higher fee if foundation plantings will have to be taken out and reinstalled.
“Some people value their plants more than their foundation. But it’s a lot cheaper to replace the plants than the foundation,” Carter said.
Foundation repair companies also can do the work, but many want to take on grading only in conjunction with other repair work. Most will recommend topsoil companies they have worked with to do grade work.
Even after you create a nice slope, vigilance is required. Grading is a job that doesn’t stay done.
“We tend to think of our lawns as being pretty static,” said irrigation engineer Dan Rogers of K-State Research and Extension, “but they’re not.” The level of a lawn rises over time, Rogers says. Tree roots push up the soil as they mature, and the environmentally friendly practice of letting grass clippings drop creates new soil at a faster rate than bagging.
That’s why sidewalks in new subdivisions are set so high above grass level — to accommodate the gradual rise of the soil level.
Carter says it can take up to 30 years for the soil around a new home to pack. “You might need to revisit it every five years,” he said.
• Word-of-mouth recommendations are always best.
• Landscaping and foundation companies can do grading as part of planting or repair jobs. They also can recommend topsoil companies for simple grade work.
• Before hiring a contractor, ask for references and an estimate.
If you have a lot of foundation plantings, make sure watering doesn’t create ridges or depressions where water can collect. Rogers says the slope should be uninterrupted.
Finally, it’s important to know what proper grading won’t do for you, says David Frey, co-owner of Kansas City Master Cos. in Grandview, Mo.
“Most people focus on grade, but it’s more important to keep gutters clear and ensure that downspouts extend out far enough (6 to 10 feet),” Frey said. No amount of soil grading will help if water is cascading down your walls because the gutters are stopped up.