Originally Posted By: MikeD This post was automatically imported from our archived forum.
This is new construction with 8" concrete walls 8 feet high. On the back wall of the house there is a 52 foot span of wall with bulkhead steps at about 10 feet from one end. There is a large crack and the wall has bowed in half and inch. Foundation was poured in September. I am thinking that this was caused by improper backfill around the foundation. Contractor was supposed to use coarse sand but instead it was backfilled with the surrounding soil which contains lots of clay.
The house is in Maine with obvious frost considerations. I have already had substantial water infiltration during rainstorms. The water flows right into the crack and doesn’t seem to be reaching the perimeter drain system that was installed around the footings.
Was this proper construction procedure, and how do i remedy this situation?
Originally Posted By: rsonneson This post was automatically imported from our archived forum.
Not reaching drain tile system may very well be a good thing. That would generally mean that the moisture is surface water and not ground water. Surface water is a problem when improper exterior drainage is present. Most of the time in new construction it is a matter of settlment at foundation that needs to be corrected to direct water away from foundation. I would recommend gutters and downspouts that extend more than 5’ from building and regrading at foundation to create positive grade away from home.
Originally Posted By: MikeD This post was automatically imported from our archived forum.
Agreed and it is definitly surface water. However the wall is bowed in half an inch in less than 4 months…how will gutters alleviate this problem…i am concerned about long term structural integrity…
Originally Posted By: lgerving This post was automatically imported from our archived forum.
If the wall has pushed 1-1/2" in 4 months it is only going to get worse.
With clay soil backfill you can count on the wall pushing more as the clay absorbs more moisture and the ground compacts. Frost in the clay is going to be another problem.
If it is written in your contract with the builder you should have the clay removed and have the wall re-enforced where it is cracked and then sealed again on the outside of the concrete wall. Clean 3/4" rock or other type of material that won't push or compact should be installed. Roof gutters and proper ground slope all help, but these are not the cure for your problem.
Originally Posted By: MikeD This post was automatically imported from our archived forum.
thanks for the advice…it is what i expected and makes perfect sense. It is very clearly stated in my contract that the backfill is to be coarse sand and it is not…I will have to hold the builder to this. I guess it would be wise to have a home inspector state this in an inspection report to backup my case.
Originally Posted By: MikeD This post was automatically imported from our archived forum.
the crack is vertical, it is very tight at the floor and widens to about a quarter inch at the top of the wall…i stretched a line from one end of the wall to the other to see the extent of the bowing and at that point is has come in a half inch at the top…I was given the suggestion that a foundation wall with a span of 52 feet like this should have some kind of extra support…like a deadman into the ground…is that true?
Originally Posted By: mkober This post was automatically imported from our archived forum.
Mike,
If the wall was properly reinforced and consists of a reasonably strong (3000 psi) concrete, a normal design wouldn't require any kind of pilaster or deadman. It's quite likely that the 1/2" inward deformation was caused by improper (clay) backfill--especially if backfilling was done before the wall was "loaded" with the floor platform (or didn't have temporary kicker braces in place).
Originally Posted By: Mark Anderson This post was automatically imported from our archived forum.
Mike…IMO it would be best for “the wall” to remove/lessen further pressure that is on the outside of the wall…and seal the crack and entire area/section of the bowed part of wall. Only way to do that is to hand dig to footing, haul all clay away, scrape `n wire brush that section of wall, use hydraulic cement in and over any crack, apply a Thick Tar over entire section of wall and then viqueen over the tar, then backfill (not with a backhoe or trencher) with 100% peastone to within a few inches of grade.
Go ahead and do whatever others have suggested....regrade/extend downspouts etc...but after you do that, your still going to have a vertical crack in your bsmt wall and have pressure against it, so future widening of the crack & leaking is still most likely going to occur. If the builder tells ya he wants to fix the crack from the inside, i would Not agree to it. Again, it will be best for the wall to have less pressure against the outside of it and any inside injection method of sealing the crack will do Nothing for that. Builders opt for this method because its much easier,much less labor intensive....and cheaper to do but its Not the best thing for the wall.
Originally Posted By: MikeD This post was automatically imported from our archived forum.
the house is a modular and the foundation was backfilled before the house was set, a few weeks later. I am getting the picture that the foundation is not designed to be structurally sound without the floor in place to hold the walls plumb. Is that how it works?
Originally Posted By: rsonneson This post was automatically imported from our archived forum.
1/2" bow in 52’? I think that it would be hard to find a wall 52’ long that was poured so straight that in 52’ there is not some type of bow inward or outward. I would guess that the crack and bow has been there since wall was backfilled and is not moved since that time. Is there signs in joist, sill plate, exterior veneer anywhere else that would make anyone believe that the movement is going on now or was present when backfill was applied. I just dont think that 1/2" in 52’ is uncommon. I also do not think that a crack in a full foundation wall that runs vertically is uncommon. I would venture to wager that if we sat back and considered every home we inspected will full foundation each of us would be hard pressed to remember more than a handfull that had no cracks. Cracks in poured foundation are typical or at least very very typical in Northern Illinois.
Originally Posted By: MikeD This post was automatically imported from our archived forum.
Thanks so much for all the excellent advice. I will post any new information on what happens when the builder is presented with this and other information.