Flooded Basement

[Devonai]

The last two storms, I've been dealing with water in my basement.  The first time, I thought something was wrong with my chimney, perhaps a rain guard had become dislodged.  I sent a drone up there to look and didn't find anything amiss.  I put a bin in the base and collected a small amount of rainwater, but was stymied as to how much could've ended up elsewhere.

Ida proved to me this morning that it's not the chimney at all, but infusion through the foundation itself.  I didn't get it as bad as some in Connecticut, only up to 2 inches in spots, but it was enough to ruin several cardboard boxes of stuff and shoes/boots.  Perhaps $1000 in destroyed items.  I ran out to Lowes and got a shop-vac, but after a couple of hours of cleanup it became obvious that the flooding had not yet ceased.  I've been down there every hour since to try to keep up, and as I'm writing this, things finally seem to be slowing down.

The good news is that my town sewer line hasn't been affected, it's only groundwater.  So my girlfriend and I haven't had to evacuate; the toilets and shower are still draining just fine.  My greatests concerns now are future events, and remediation of any hidden damage.  I do have one finished room in the basement where perhaps one inch of drywall got wet on three sides and I'm not sure I should abide by just a dry surface.

Thoughts?  Should I call Serv-Pro or somebody to take a look?  Should the drywall come out?  I'm basically clueless.

[Grandpa Shooter]

The most common attempt at avoiding a wet basement when water is coming through the lower wall or through cracks in the footer is jack hammer the floor at the base of the wall and dig a trench around the outside walls, put in french drain pipe and back fill with gravel, and at a suitable place cement in a basin for a sump pump and pump the collected water out of the basement.  You can leave the gravel uncovered, or cement over it if you prefer.  I suggest leaving the gravel uncovered for awhile to make sure the system is working, otherwise you could end up having to jack hammer the cement you just put in to increase the pitch to the sump pump or make other corrections.  Do not use a wall coating thinking it will solve the problem.  That just allows water to build up in the wall, or undermine the foundation since it needs to go somewhere.

[Bogie]

Tonight, or tomorrow, take out about 6-8" at least, of the bottom drywall. It'll wick water, and the water inside will also be humid. Just get a circular saw, draw some chalk lines, and go to down. Drywall is easy to replace, as long as you aren't doing the bottom 8' or so. No, that wasn't a typo...

[Bogie]

Crank  you air conditioning for the basement, and if you have a dehumidifier, run that too.
 
Most "sump pump" installations will have a small "trench" around the perimeter inside the basement, going into the sump pump cavity.

[RocketMan]

If you have what's called a "floating slab", there should already be a drainage system under the floor slab.  If the drainage system is not working properly, then water will flood your basement during heavy rain events. 
Look at where the slab butts up against the concrete foundation wall.  If there is a small gap between the slab and the foundation wall, then you have a floating slab.  You do not want to plug that gap if it exists.
My home has a floating slab, and the drainage system was connected to the drain lines from the gutter downspouts.  The drain lines leading away from the slab and downspouts had been crushed when the previous owner had put in an asphalt driveway up to the basement garage door.  This caused the basement to flood several times a year.
It took me quite a while to figure out what was wrong with the drainage system, but after repairing it we've not had the basement flood since.

[Devonai]

Thank you to everyone who replied.  The ground water has since ceased.  All I have left is about five minutes with the shop-vac, and making sure our appliances aren't damaged.  Tomorrow is a trip to the town dump.

No floating basement, unfortunately.  The house was built in 1935.  No sump pump, either.  Either this amount of rain is unprecedented, or previous owners simply cleaned up every so often.  This year is the first time we've had problems since we got the place in 2016.  House is not in a flood zone.

As far the drywall, we were considering demo'ing the basement room anyway.  It wasn't particularly well-built in the first place, and now that we have mini-splits, there's no reason for either of us to spend time in that room except for my weight bench.

[bedlamite]

The most common attempt at avoiding a wet basement when water is coming through the lower wall or through cracks in the footer is jack hammer the floor at the base of the wall and dig a trench around the outside walls, put in french drain pipe and back fill with gravel, and at a suitable place cement in a basin for a sump pump and pump the collected water out of the basement.  You can leave the gravel uncovered, or cement over it if you prefer.  I suggest leaving the gravel uncovered for awhile to make sure the system is working, otherwise you could end up having to jack hammer the cement you just put in to increase the pitch to the sump pump or make other corrections.  Do not use a wall coating thinking it will solve the problem.  That just allows water to build up in the wall, or undermine the foundation since it needs to go somewhere.

I did this several years ago. Lots of work, but my basement has been bone dry since.

[JonnyB]

Does the house have rain gutters and downspouts to direct the water away from the house? If not, start there. We removed ours to replace the soffit and fascia (in the driest summer in fifty years), then got five inches of rain over the past ten days. Water in the basement. Not much, but we’ve not seen any before, despite 2019 being the wettest year since Noah’s ark.

JB

[brimic]

Gutters/ downspouts first, then take a close look at your grading. The old houses usually have clay drain tile around them that eventually fills in with silt, but the idea is that by the time that happens, the ground will have settled/ compacted and the water should run away from the house.  If not, consider doing some grading adjustments.

I live in a house built in 1960, it has a pretty good drain tile/sump system, but I still get some water do to grading issues (the water runs downhill vertically about 15’ from the road towards my house, and I think my house is built on a spring, as the sump pump runs regularly even in the middle of winter.

[RoadKingLarry]

No thoughts about an indoor pool?

[Devonai]

We "enjoyed" the pool while it was there.

The downspouts are reasonably far away from the perimeter.  I'm 99% sure there was never anything like a clay drain tile in place.  Grading improvements on the north side of the house are definitely something I'll look into; Henri and Ida caused water to pool up to a few inches on that side.  However, the casement windows are only a few inches off the ground, too.  Water didn't exceed that height during Ida.

As far as the drywall, I've long considered just demolishing the basement room as it provides very little utility for us.  In fact, my go-to GC was available today and they're down there right now.  Once the room is gone, they're going to sanitize the whole basement.

[Hawkmoon]

Some regrading may be in order. My house was built in 1950, and I know my front yard doesn't comply with current codes. The International Residential Code (which Connecticut adopts) requires:

R401.3 Drainage. Surface drainage shall be diverted to a
storm sewer conveyance or other approved point of collection
that does not create a hazard. Lots shall be graded to
drain surface water away from foundation walls. The grade
shall fall a minimum of 6 inches (152 mm) within the first 10
feet (3048 mm).

[JTHunter]

This is why I'm glad I just have a crawl space.  In fact, my back yard actually slopes upwards by about 12-16 inches over 25-30' horizontal.
It can't be regraded as the old septic laterals are still buried there, even though they haven't been used in over 30 years.