In 2013 we purchased a house built in 1939. A portion of the basement was finished and used as a bedroom at some point (no idea when). A couple weeks ago I went to replace the carpet with laminate flooring, and discovered a wealth of problems:

1) The basement floods every time it rains. This was not evident because the water remained beneath the subfloor, where it had completely rotted the sleepers. I ended up removing the entire floor down to bare concrete.
2) Fiberglass and mineral wool insulation was installed below grade against bare concrete foundation walls. No vapor barriers were used anywhere. It was a mold fiesta.
3) The studs used to attach drywall had rotted where they contacted the flood-prone concrete floor.
4) When I pulled off the drywall, I found that wind-driven rain had infiltrated the siding (no building fabric), rotted all sheathing up to 2' above the knee wall, and rotted the 2x4 sill plate that sits on the knee wall.

Here is a photo of what was left of the sleepers:




The source of the water is an old, walled-off the exterior door that used to provide access to the bedroom:




When the former owners removed this door, they slid a piece of plywood into the old doorway, and framed it in with untreated lumber.



Then they put some kind of hardboard on the exterior side, and backfilled the stairwell with brick (!).



When it rains, water cascades into the basement between the "new" sill and the concrete bulkhead. I wouldn't believe it if I didn't own it.



I'm stumped how to fix this. Here are my options, and I could use some help choosing one, or coming up with something else:

1) Replace the plywood and framing from the doorway with exterior grade OSB sheathing and PT lumber. Install drainpipe below the former concrete door sill, and drain away from house. Apply Grace Bituthene system (primer, Bituthene, Hydroduct, mastic) to the outside. Backfill with washed gravel.

2) Build a proper exterior wall (sheathing, Tyvek, siding) all the way down to the former door sill. Finish with an egress window well to keep dirt and water away from the old door opening.

3) Fill the former doorway with poured concrete, using waterstops and rebar attached to existing foundation. Finish with Grace Bituthene system on the outside. Backfill with washed gravel.


Thanks in advance for any advice!

 

Without a doubt, #3 is the best course of action... in addition, brush on a bonding agent to help bond the cold joint between new and old concrete. Bridgeman45 can probably help you most with the concrete details if you need specific advice on how-to.

 

1st you've got to get the water AWAY from the structure so start digging,,, hopefully you can direct the wtr into a drainage-to-daylight area otherwise you'll need to install a pump ( zoeller m-53 ) [ no $ interest - they're just the best for the $ ] in a sump,,, after you make whatever structure repairs are rqd & have suitable below-grade surface, we'd trowel on a layer of HLM5000 or equal then protect that w/pond liner,,, pretty easy work for this part you keep the water away & you'll have a decent finished job - good luck !

( bdge must still be sleeping )