Basement Leak - Recommended path forward
Moved into a gut-renovated 1920s construction townhouse in a part of Brooklyn that is not in an official flood zone, about a 18 months ago. two floors and a third english basement.
A few weeks back a heavy rain exposed an issue in our dug out english basement, which is currently finished as a 2bed apartment. Noticed signs of water on the floor entering from two or three likely spots as there was dirt residue on the floor after it has dissipated.
We’ve since had a waterproofing company dig out and expose three small sections of the foundation from the interior in the front, side (shared), and rear basement walls. Images can be seen here: https://imgur.com/a/OkhS97V
None of these three sections have a deep enough footing to install a french drain, which does not already exist. Bad news for us.
We were given two options as a next step:
1. Open up more wall and seal old brick/stone wall with cement/sealant. Then wait for heavy rain to observe if mitigated.
2. Install channel where the footing is deep enough. For the sections where it is not deep enough (back side of house) recommend underpinning to extend footing and then install a French drain. Three total sump pumps.
Clearly option 2 is the extreme route, and option 1 is really just a hail mary bandaid. I’m wondering if anyone here has prior experience with this sort of problem, and the steps y’all have taken to mitigate. Currently in the research/second opinion phase of solving this problem, as I’m not looking to rush into any decisions.
Thanks.
lukelevis
in General Discussion 1 month ago
6
Please log in, in order to post replies!
6 replies
amt230 | 0 months ago
What a bummer, sorry to hear it. I definitely would try to gather more info before making any decisions – particularly where it sounds like you have leaks on 3 walls, including the party wall?
If you’re able to spend some time in the next big shower with an umbrella and some patience, even that could be a simple first step, and I’ve discovered the source of some (ultimately minor, solvable) leaks that way. If you have water pooling near your foundation that might help you divert and avoid larger issues. For example, do you have a drain in your garden entrance? Otherwise all the sloping and steps down is just a funnel for water into the apartment.
Good luck!
chloereed | 1 month ago
Hey, thanks for the details. From what you’ve described, Option 1 (just sealing the walls) might help a little, but it’s mostly a temporary patch—water will likely still get in during heavy rains.
Option 2 (underpinning, French drains, sump pumps) is disruptive and pricey, but it’s the only real long-term fix. Multiple sump pumps are normal for backup. If you want peace of mind, this is the way to go.
Also, make sure whoever does the work has experience with English basements in older Brooklyn homes, and consider a structural engineer’s input for the underpinning.
Brownstone Home Inspection | 1 month ago
i just looked at the photos for the first time. i am going to talk a little about this to see if i can get you to understand that that space you are trying to keep water out of might possibly not be a basement, but a cellar, which was never designed to have usable space such as a recreation room in it and NEVER a sleeping room (it was never meant to be finished).
if this house was a “flip”, this could be where your problems began.
having that footing so close underneath the house says many things to me. it sounds as though it is built like my queens house: 1920’s, two stories over a CELLAR.
Also, i believe that i saw a ceramic tile floor over concrete. in an era when everyone wants to put down other types of cheap, quick to install flooring, why would someone go through the trouble of putting ceramic tile down in a cellar? because they know that if they used anything else, moisture or water might ruin any other type of flooring before the ink dries on a sales contract.
“English basement” is a term coined by the real estate industry so they can sell houses with living space in the basement without actually having to refer to that space as being in the basement or – worse yet – cellar. a basement is a space that is even a little bit below grade at the curb (there is an exception to this but it is a bit complicated). A cellar is a space that is more than 50% below grade at the curb. so even though i have a space under my house that has small windows (12″ high?) at the front of the house and even though this space opens as a full height floor at the back of the house with a door i can walk out of into my back yard (built into a sort of hill), this story in my house is technically a “cellar”. The DOB does not have a definition for an “english basement” in their written material and i have never heard the term used in any of the construction classes i have taken. it is a term used by people who sell houses to mislead unknowing buyers and it has been around so long that it has become accepted as part of the vernacular. if this space is a cellar, it was never meant to be used as anything but utility space and had probably been originally designed in a way that a little water coming in now and then would not be an issue.
i have suggested this might be a “flip”. if it was a flip, know that when people buy houses to fix up for quick sale and profit, they make all sorts of enhancements to the houses to make them appear more attractive to potential buyers without actually caring that a house might have been designed and built a certain way for a reason and many of the changes are either impractical, illegal, or would cost a fortune to do correctly. Finished space in cellars is a major concern with these properties (another trick is enlarging the parlor floor by removing the vestibule and leaving unknowing purchasers with a pair of drafty 19th century doors as the only thing between a warm living room and artic air).
No matter what you do, do not allow anyone to dig around and under that footing. Also consider that some of the water might be coming up through the floor. In so far as concrete to stop that, there really is no waterproof concrete but 4500 psi comes close. when i inspect these houses and we suspect an issue, i will often put a moisture meter down on the floor to see what is going on and we will often get 85% mc on the floor. that is a lot of moisture.
Keep reading about waterproofing solutions. The term for working from the exterior is “positive” side but if this is coming through the floor, you will have a hard time. I also mentioned “negative side” waterproofing in a post below.
be aware that if you have wood down low and it gets wet – like over 25% moisture content – termites can thrive (that is often the issue with the joists supporting the floors at the front of “english basements”, they are 6 or so inches below grade and they get wet and the termites attack them). In these situations, i advise my clients to get a couple of dehumidifiers in the space and keep them set at 45%. Keeping the humidity below 45% will not only make it harder for termites to thrive but will also help keep mold away. i recently had a situation like this and also told the people to install vents in the drywall to dry the cavity out between the drywall and foundation wall. you might want to remove the drywall altogether.
so readers know, I became a home inspector at the urging of a customer after (quickly) finding a leak on her house that the “roofer” could not locate after two extended visits. In addition to providing home inspection services for buyers, i provide maintenance consultations for owners and condo boards and building envelope leak investigations (roofs, windows, walls, not cellars).
Steve
brownstonehomeinspection.com
Brownstone Home Inspection | 1 month ago
cate is correct that it is not a good idea to seal a wall from the inside as the sealant will eventually fail. this method is known as “negative side” water proofing. you can read about it and the products used to perform this sort of water proofing. They often say it can be done, but must be maintained.
as cate says, the outside is better. they used to use flashing cement but now a days, people have moved to water proof membranes.
there are other ways to address some of this, and without great expense, not all will be perfect.
and english basement might be easier to fix than a cellar though as the basement only has a little bit below ground. in so far as the cellars in these old houses, they are mostly underground and in many cases most of them have faced these challenges over the years.
cate | 1 month ago
One other thing: It is never a good idea to install sealant from the inside. The pressure of the water will cause the sealant to fail and cause even more problems. You would have to go in from the exterior, dig down, repoint, and waterproof. It’s expensive and disruptive. I would look for other solutions first. If you plan to redo the concrete in front or back anyway, that’s a good time to waterproof the foundation from the outside.
cate | 1 month ago
So sorry to hear of these troubles. Sounds like it’s a very small amount of water? It’s good you’ve opened up the walls to see what is happening. But you need more information. The water could be coming from a neighbor, concrete in front or back that is not sloping away from the house properly, a problem with your roof or gutter, a sill, brick that needs repointing, groundwater seeping up from the ground and no vapor barrier in the cellar, puddling in the front or rear yard, a blocked drain in the front or rear yard. There are many possibilities. I take it there is no cellar, only the slightly below ground garden level? (Please be aware the city’s 1920s date is probably wrong — this sounds like a mid-19th century Italianate.) Maybe talk to your neighbors with similar houses, see if they’ve had similar issues and what they did. Wait for another storm and see if it repeats. Observe the location and what is is close to. FWIW we had a persistent leak in the rear of our cellar for years that nothing could fix until we removed the PermaStone cladding the ground story and repointed the brick. Voila! More recently we had mysterious ground water seepage in the front of our house that started when we installed a front garden in 2019. The problem stopped a few weeks ago when my neighbor got a new roof and gutter. Our cellar is now dry despite some terrible storms lately.