I Have an 8′ high 40′ long concrete block basement wall. The home is a raised bungalow so I sit roughly 5′ below grade. I have developed a verticle crack mid span in the wall several years ago. the crack appears to be getting worse over time.
Appart fom strapping the wall horizontally with steel framing and lagging it to the other blocks I’m looking for a simpler solution to holding the wall back. I’ve considered filling the voids with concrete, using appoxy in the crack, the steel framing and excavating from the outside.
Does anyone have any other ideas?
mykola
Replies
There are outfits that specialize in this. They have special anchors that can be installed without excavation in many soils.
But if it's a minor crack (less than about 1/8" gap) then it's probably "normal" and not worth worrying about.
It sounds like the crack is from pressure on the wall from the backfilled soil. A long unbroken wall like that is extra suseptible to such things.
If hired to fix the problem I would have to dig up what's on the exterior of the walls to see what it's backfilled with. It could be that proper backfill for your conditions is the only thing needed to prevent any additional damage.
Having said all that, if the crack is from the ends of the building settling more or less than the middle and the wall isn't actually being pushed inward, then there's little you can do short of making sure the ground level water drainage is away from the building, or a major footer replacement.
Some careful measurements and a few string lines will most likely show what's going on.
Beer was created so carpenters wouldn't rule the world.
You are probably experiencing pressure at the top soil line from expansion during the frost season. I'd excavate, push the wall back out and install a pilaster in the midspan. Or, I'd build one inside the basement and just live with the bulge.
You probably have clay fill.
Bob's next test date: 12/10/07
More info neded.
Is this a crack that is wider at the top then the bottom? Vice-Versa?
Does the wall have a bulge in it as if it is being pushed into the living space?
Safest bet is to excavate from the outside and try to determine the cause. May be lateral soil pressure, may also be foundation settling at the ends or in the middle of the wall but no lateral soils pressure.
Reinforced pilaster, or even two, as suggested
Jeff
I've seen steel columns ( heavy 4 inch square ) installed between the floor diaphragm and the basement slab and then wedges drive along the line of the crack to stop any further movement.
There are small plastic devices that you can attach to either side of the crack to monitor movement, I would advise using these to see if things are still moving.
Dovetail is right, more information is needed.
What is the width of the crack at the top and at the bottom?
If you hold a straightedge to the wall in the vicinity of the crack how flat is the wall?
Is there any lateral displacement of the wall at the crack?
Does the crack open or close seasonally?
There are strain gauges you can buy and apply, this would be a good idea.
A cheap strain indicator would be a small pane of glass (like an old single pane from a divided light window) epoxied at the edges on either side of the crack, cover the pane with duct tape on the inside face and a few stripes of tape on the outside face so nobody gets hurt. If the wall moves the glass will crack. Not recommending it, just an idea.
I'm as yet unconvinced that you have a lateral pressure problem, these usually show up differently.