Can an underground drain pipe cause water seepage into basement where floor and wall meet in the front and side of a house?

Question

We have three water issues on one side of our 1934 house. Our house sits beneath our adjacent neighbor's 2018 cruise ship of a McMansion that runs the full length of our home and backyard four stories high - it's mammoth and blocks our western exposure. This may not be the cause of our problem but it certainly didn't help the water table.

In this area, we have a window well and a kitchen covered porch with no gutters. The porch has four stairs down to a walkway out to the backyard. Fortunately, the ground slopes down from our front yard to our back, but it also slopes down to us from our neighbor and we have a damp basement from water running along our house the entire side.  We need a multi-pronged solution to get the water away from settling above and below which leads me to our first issue.  

1. A puddle forms between our window well and our kitchen porch about three feet out from the foundation. It only happens during heavy, extended periods of rain, and we suspect regrading and installing a surface drain at the bottom of the kitchen porch steps can redirect this surface water away and around the porch. However, water may be flowing underneath the porch because the 1st porch step is rattling now and a small area on the stoop. Water will flow down that walkway in torrential rains because it has sunken towards our house (vs. away) since it was built in 1967. In the basement beneath the porch and walkway, a double closet has water stains along the carpeted floor and is moist but not wet. The walls above look fine. We've caulked and added a cement lip on the walkway which is cracking because the water is getting underneath. Unfortunately, we have wood paneling in the basement bedroom at the end of the house, so we don't know what the walls look like there where the walkway steps down into the backyard. But our basement is very humid and musty smelling which leads to our other more confounding issue.

2. Water seeps into the basement bathroom during these heavy storms where the wall meets the floor underneath the sink. Our den bathroom above it has no problems. We don't have water running down the walls or any water stains in the basement. Is it related to the pooling above or does it mean the adjacent underground exterior drainage pipe that carries stormwater from a downspout in the front of the house has been compromised? We have a large hickory tree next to our home towards the front of the house. As far as we know, the pipe is original and connects to two other downspouts in the backyard and deposits the water somewhere out in the yard or street?

3. In the front of the house, we have wet drywall in the corners of a basement wall that lies below our front door stoop. I also discovered water staining along the baseboard of the stair landing next to it.  Again, this may indicate our underground drainage pipe is compromised OR is it our front door stoop? We do have cracking mortar on the door stoop and water stains along the front door frame. One estimator said he thinks the water is behind the door frame and causing the basement moisture since the door stoop slopes away from the house.  

So how do we resolve these problems? We've had a slew of experts suggest various approaches such as but there is really no consensus:

• Install new large 6" gutters and enlarged downspouts all around the home. Disconnect all underground downspouts and install those ugly accordion pipes to extend all downspouts out to the street below in case the underground pipe is failing or to avoid more problems in the future.

**Install a new front door stoop and add a portico to address stormwater from above the windows where no gutters exist. Will this resolve the wet drywall or is the underground pipe the culprit?

OR

*** Regrade and install a swale along the side of the house from the front midway to the kitchen porch, but that doesn't address the walkway sunken towards the house which likely contributes to our damp basement. Nor the cracks from the water incursion in the basement bathroom.

OR

**** Waterproof the exterior side wall from the front to the kitchen porch where the puddle exists and the water comes in the bathroom. Regrade that area and add a surface drain at the bottom of the kitchen steps. Lay new flagstone over existing walkway and regrade cement underneath so water flows off the walkway into existing ivy. Or should we rip out the walkway and start over?   ***** Hire a mold remediation expert to determine the cause of the damp basement. Then pick a solution based on their findings.

Aaaaahhhhhhh - not sure where to begin.

I'm wondering if it's possible to run a camera down the underground drainage pipe from the front downspout to the backyard to see how that drainage pipe looks on the side and front of the house and go from there?

At this point, we're really shooting in the dark. Anybody have any experience with these problems or thoughts about next steps?  Thanks.

Answer 1

The 2018 neighbor house likely reduced the severity of the water issues. Modern code typically dictates permeable surfaces, rain drain and perimeter drain separation and the new house likely has a basement with perimeter drains that remove some of the water table especially if their basement is lower than yours.

As far as your problems go, your house is from 1934 and the basements weren't designed as living spaces, I've converted 3 basements from similar vintage houses into modern dry spaces in the pacific northwest where we get lots of rain and always have water in the water table.

The first place to start is the raindrain/gutter/downspouts. Your raindrains and perimeter drains are likely clogged and connected. You should have separate solid 4" pvc pipe for the raindrains that exits to either the storm drain or twins right at the street with the sewer/perimeter drains. This takes care of most of the water, all the water that hits your roof.

The second thing you'll need to deal with are your perimeter drains, the 4" perforated pipe that surround the footings of your house. In 1934 they used vitrified clay pipe in segments. You'll need to dig around your entire house to the footing ( you might not have a footing ). You'd then put perimeter drain pipe down and around the house and have it drain to either a gravity sump well or a powered sump well ( depends on your grade and the sewer / storm connection ).

Once your pdrain is in place, you'll waterproof your foundation. You can either spray the tar water proofing, roll the tar waterproofing or install dimpleboard or do both.

Once those 3 things are done you can work on fixing up the inside of the basement. Your 1934 basement likely has no vapor barrier and no sub slab insulation. This means that water vapour will wick into the concrete slab and diffuse into the living space. It also allows radon to enter your basement. The lack of insulation allows any water in the relatively warm air to condense onto the basement slab and cause condensation.

The best path is to rip out your slab, add drain rock, add vapor barrier, add insulation and re pour the concrete slab. At this point your basement is dry. If you are re-doing your slab then you should also update the services running to your house, sewer line, water line, electric if you want a panel on a non exterior wall.

This part of the work is the most expensive though so if you've done the first 3 pieces then you could likely take some short cuts on the interior work. Put down some vapor barrier on the existing slab, put a layer of XPS, put a layer of ply and use waterproof LVP as your flooring. Remove the bottom 12" of drywall replace with paper free drywall and use cellular pvc baseboards - both impervious to mold/moisture.

Depending on budget, how long you plan to live in the house, and if your grandchildren will inherit the house would dictate how to tackle the basement.