Rise in basement floor - can't find cause

lapwarren · 02-28-2009, 04:10 PM

Over the last few years during the winter (I live in Michigan) a part of the poured concrete floor in my walkout basement rises slightly in a straight line that begins near the middle of the outside doorway and extends straight back to the utility room where the washer, dryer, furnace, etc. are. The concrete is not broken or wet, although it is slightly flakely along the line of the rise. Thinking it was a broken pipe, we consulted our plumber. He says the pipe that leads out to the septic tank is located in a different area, and that building code would have prevented any pipe being laid underneath the outside doorway. (The house was built in the late 70's). We doubt it is a root because the floor levels out when the weather warms up. Any ideas about what could cause this?

Bob Mariani · 02-28-2009, 04:58 PM

Water pressure under the slab along with improper or insufficient gravel for drainage beneath the slab. Is your grade sufficient away from the house? Are all your downspouts in good running order? Use a metal detector to see if rebar was used as required in the slab. It may mean you need to start over and have the job done correctly. It is not a DIY type of project.

ccarlisle · 03-01-2009, 07:42 AM

When was your house built? Do you have a sump pump? How 'bout your neighbours?If so, does it run OK, ever? Are you sitting on a clay soil? you may not have the answer to that question at the tip of your tongue but you may have an idea about your neighbourhood from the gardeners or the gardening centers, perhaps even your City Hall...

We have a problem know as 'pyrite' soli up here. Google it.

lapwarren · 03-05-2009, 02:03 PM

We have sufficient grade, as no water ever collects. There is one downspout on the side of the house that the bottom part sometimes gets knocked off. I'll check it out and find out about the rebar, too. I wonder if the thaw-freeze-thaw-freeze pattern is aggravating things.
Our soil is more on the sandy side, so clay content is probably not the problem.

The actual cause is probably that we decided to sell the house. An amazing number of things have broken down since we made that decision: The upstairs bathroom wall suddenly fell in, the garage door opener exploded, the furnace thermostat stopped working, etc., etc., etc.

JazMan · 03-05-2009, 03:30 PM

AH.....That's it! The actual cause is probably that we decided to sell the house.

The house has a brain.

Jaz

Bob Mariani · 03-05-2009, 03:57 PM

Quote:

Originally Posted by JazMan

AH.....That's it! The actual cause is probably that we decided to sell the house.

The house has a brain.

Jaz

Since your post the brain has also exploded...