Landscape Drainage Issues

During a recent consultation with a young couple who purchased a home last fall, they mentioned they had issues with water in their basement. There can be many causes for this common problem. Clogged gutters, hardscapes next to your foundation, a poorly graded yard, and neighboring yards are common reasons and potential for water issues around homes. Following, I'll review potential solutions for each of these problems.

Gutters

The first place I always look is up to see if clients have gutters and if they are clean. Clogged gutters or no gutters at all cause the majority of basement water problems. A simple cleaning allows the rainwater to go away from the foundation instead of overflowing and running into window wells, egress windows, or right next to the foundation.

Hardscapes

Concrete next to the foundation - like a sidewalk, patio, or a driveway - is another problem area is,. These can channel water from the large concrete surface area directly to the foundation. The solution is to backfill any gaps next to the foundation with sand and then caulk with a flexible concrete gap-filling caulk. Sometimes it requires more intervention, such as removing concrete and regrading. This is best left to professionals.

Poorly Graded Yard

At the young couple’s house, the grade of the soil was sloping towards the foundation, creating a low spot where water collected and slowly soaked in next to the foundation and then into the basement. If you have a grade that slopes towards the house and no gutters or overflowing or plugged, all of the rainwater from the roof is going into that low area. There, it seeps into the basement, sometimes through eroding joints in the block wall construction used for most foundations.

Water can also infiltrate through concrete walls, too. It will run along the foundation and seep up through the space between the concrete floor and the foundation wall. There are drainage systems in newer foundations that carry water to a sump pump and out through a pipe into the yard. Even then, I’ve seen water come into the basement. It trickles in through the foundation when there is a reverse grade or plugged gutters.

Neighboring Yards

I’ve encountered situations where a neighbor’s property slopes towards my client’s property, funneling runoff into their foundation. This is very common in smaller urban lots with 10 ft between houses and 2 ft of that is sidewalk. The water needs to move away from the foundations and then out the front or the back of the property. If the area between the houses is close to level, the solution is to construct a swale (a shallow drainage depression that carries runoff) so the water either flows out the back, front or both. This can be vegetated with grass or protected with a polyethylene sheet plastic, and river rock. This is usually an effective and inexpensive fix.

Drainage Trench

If the houses are close together and one property is significantly higher than its neighbor, you will need to create a different solution. Sometimes it’s possible to raise the grade on the lower property. To determine if this is possible, you need to see how much of your foundation is above grade. If there’s room to raise the grade high enough to be above the bottom of a swale, you are in luck. Many times, you will need to install a window well so the regrading doesn’t cover the basement windows and create a new entry point for water. This allows adding soil against the foundation and raising the grade next to your house. The bottom of the swale created by doing this needs to be lower than the regraded soil, or it will just let water run into your foundation.

A retaining wall may need to be installed if a neighboring property is significantly higher than yours. This allows a swale to be created to carry water away.

A French drain is another solution. This involves digging a trench at least 2 feet deep with a slope of 1” per 10 feet. Line it with a quality landscape fabric at the bottom of the trench and place a 2’ thick layer of pea gravel on top of the fabric. On top of the gravel, you’ll place a perforated drain tile with a fabric sock. The trench is backfilled with pea gravel, up to 8” below the surface of the soil. Fold the fabric back over the pea rock to cover it and prevent soil from getting into the rock, which would impede its ability to drain properly. If there is significant surface water, you can have vertical tile with a grate to expedite drainage.

There are other situations where a large backyard was a drain for several other yards, funneling all the runoff towards the house at the bottom of the slope. We used diversion dams or berms to channel the runoff to the sides of the property. One property had inches of mud on its patio every time it rained. We created a rain garden up on the slope that infiltrated most of the runoff. The overflow was directed to a vegetated stone walking path. There it ran into a large swale that carried the remaining runoff out to the front of the house, where it flowed into and watered the lawn. (I’m not sure I understood this paragraph, so let me know if I changed the meaning too much)

Conclusion

There are many solutions to drainage issues, but they don’t have to be costly or invasive. You may need to call in a foundation, a waterproofing/drainage contractor, a landscaper, or a gutter installer. These fixes are much more expensive and still may not solve the problem if you have a reverse grade or other landscaping issue. I can help you wade through these options and come up with a plan that fits your situation. Contact me and arrange a consultation. I’ll be on your side.