In my post about the sump pump, I discussed our concerns about water in the basement. Those concerns have proved well founded, because after some heavy Spring rains, it happened. Our interior weeping system directs water under the concrete slab to the sump pit and the sump pump pumps it away, and this system is working great. However, water doesn’t always come from below. Because of the thick, clay soil, water following the path of least resistance can come right through the brick basement walls. That water is coming in above the footer curb in the basement and then drains onto the top of the basement floor, bypassing the weeping system completely.
There are ways we could have avoided this. The preferred method is to excavate around the outside of the house and install a water barrier on the outside of the basement walls, but our house is less than four feet from the neighboring houses to either side, risking structural collapse of both our basement and theirs. Another method is installing a dimpled plastic membrane on the inside of the basement walls that provides a path for water to drain down below the slab and into the interior weeping system. We didn’t do that for a couple reasons. First is the potential for damaging the bricks, both from persistent water and from freezing. Second is that the membrane would have to wrap over the footer curb, and we’d have to frame walls in front of it, further reducing our floor space (by about 50 square feet). While we do plan to insulate inside the brick walls, we’re going to do so without a vapor barrier, so that the bricks can dry if they get wet. The interior-facing side of the footer curb will remain exposed, or at most covered by trim.
Old downspout accordion
While we’re exploring ways to divert water that comes through the walls, the bigger focus is on keeping water away from the basement walls in the first place. Recently it poured, and I discovered that the downspout I’d put in after we removed the back porch was clogged, causing a fountain at the back corner of the house right where we were getting most of the water. Once I fixed that, the downspout was splashing about fifteen feet into the back yard… and then running across the patio to the other corner of the house. Worse still, our neighbors’ downspout was clogged and all the water from half their house was cascading into the gangway. The downspout we had on that side was running across the gangway and wasn’t sloped away from the house, so water was draining to the same corner. I got the water from both our gutters to divert to the stone-filled catch basin, but something more permanent was needed.
I ran to Home Depot and got some supplies, then got up on a ladder and reconfigured our downspouts. The gutter on the gangway side now drains across the back of the house between the first and second story, where it joins with the other downspout. It then drains about twenty feet from the house, but I plan to extend that to thirty. I also unclogged the neighbors gutter and ended the waterfall in the gangway. Since making this change we haven’t seen additional water, but I’m not yet convinced we’ve solved the problem. I have some other steps I can take if we see any more water.
June 15, 2016 at 9:57 am
Great post, My flat roof goes straight into the sewer. However, I am getting a little water on my brick 2-Flat only on high rain days in between one of my neighbors. I think all his water from his gangway concrete walk is adding to my side. Because of the old foundation, spacing(as you mentioned), and elevation; I was thinking of putting in a French trench along the side of the house toward the back to a catch basin / then pump out as needed to the ally. I have not heard of anyone doing this method in our small Chicago lots. Any thoughts?
I know some just concrete each side of the house to “guide” water away from the house either to the front or back… concrete my whole property, not my kinda of style. I certainly don’t want to “elevate” my side to let the water pour into my neighbors either.
June 15, 2016 at 12:02 pm
That sounds like a good plan to me and in fact it’s very similar to what we’re planning down the road. I want to rip up the concrete sidewalk along the house and dig down a foot or so, sloped to a center french drain. I’ll put down a plastic barrier that extends to the houses on either side (caulked/glued to the foundations), a 4″ perforated rigid pipe in the bottom, and cover the whole thing with pea gravel. We’ll put pavers down in place of the sidewalk, spaced apart so water can drain through the pea gravel. We’ll direct the drain to a backyard rain garden. I plan to direct my downspouts on that side of the house into this same drain.