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How to Seal the Outside of Your House with Sand

If you have a leaky basement no matter how diligent you are about having gutters and downspouts in good repair, the problem might be the grading around the outside of your home. Low spots in the soil next to the foundation makes it very easy for water to run down through your foundation and into the basement. Here's one easy fix using plain sand.

Even if the soil and landscaping around your home appears to be sloped and properly draining water away, there can be low areas and crevices that aren't easy to spot. This will be more common with older homes, especially if you have sandy soil to begin with. Using anything long, skinny and rigid, walk around your home and see if you can slide it down into the soil right next to the foundation. A driveway marker, poker or a very long mechanic's screwdriver works. See if you can slide the poker down easily. Check about every foot or so. If you can slide the poker down more than a few inches, water can get down there, too.

Using a flat shovel, pull the soil away from your foundation anywhere it will give. Trickle the play sand down the voids. You might be surprised at how much it takes to fill it. Sand works because, like water, it will fill in and seal even very small cracks and crevices.

The sand will settle over time and with some more rain. Recheck it every week or so and pour more sand down. You can hasten this process by simply running water from a hose along the edge of your foundation. Be aware that this will probably cause some basement leaking, but it will also tamp the sand down. Keep refilling low spots with sand until you're sure it's all settled.

In places where you have grass growing along the side of your house, you can now set several inches of topsoil along the edge. Tamp it down and apply grass seed. As the grass growns, the root system will further prevent water from going into your foundation. If there is decking or cement up against the foundation, all you need to do is get as much sand down into any crack you see.

Of course you also want to do everything you can to divert water from your home's foundation and this means having gutters, downspouts and diverters clog-free and in good condition.

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