Anyone a structural engineer?

-
slantflat

slantflat

Well-Known Member
Joined
May 24, 2014
Messages
215
Reaction score
129
Location
Georgia
Hi everyone.

This is what I have going. The front wall of my basement has failed due to a tree that used to be in the front yard. It's a block foundation and the roots pushed against the wall and it's bowing inward. It has several large cracks and it's just started to leak when it rains.

What I want to do is dig out the front of the wall, line the front and inside with plywood, run lag bolts through and methodically tighten the bolts and let the plywood true up the wall. Then form up the front of the wall and pour concete over the plwood and then fill back in. The concrete would encase the plywood and also serve as waterproofing, and also a footing for a brick façade.

My question is, will doing this suffice to keep the front of the house from falling in, or will the rest of the joints break and then I'll have a wall of loosely stacked block that isn't very supportive. Or should I spend the boatload of cash and have a company come in and rebuild the wall? Any other ideas I could consider?

Thanks everyone.
 
slantflat said:
Hi everyone.

This is what I have going. The front wall of my basement has failed due to a tree that used to be in the front yard. It's a block foundation and the roots pushed against the wall and it's bowing inward. It has several large cracks and it's just started to leak when it rains.

What I want to do is dig out the front of the wall, line the front and inside with plywood, run lag bolts through and methodically tighten the bolts and let the plywood true up the wall. Then form up the front of the wall and pour concete over the plwood and then fill back in. The concrete would encase the plywood and also serve as waterproofing, and also a footing for a brick façade.

My question is, will doing this suffice to keep the front of the house from falling in, or will the rest of the joints break and then I'll have a wall of loosely stacked block that isn't very supportive. Or should I spend the boatload of cash and have a company come in and rebuild the wall? Any other ideas I could consider?

Thanks everyone.
Click to expand...
How wide and how tall?
 
Pics from inside and out would help. Eve or gable wall? Size of damaged area? How far did it push? Which direction do your floor joists run? What size are they? What size and support do they have in the center of the span? Is the rim joist solid?
 
Ya I know pictures would help, I don't have any way of putting them on here. Yet another reason to move into the current century. But I digress...

Eve wall, the whole wall has cracks running throughout it, wall is bowed in almost an inch, floor joists are 2x10s (which are 1 3/4 by 9) and run the length of the wall, rim is good. There's a wall that forms a bedroom about half way across, which I assume is a supporting wall, but it doesn't go all the way to the back of the house.

Question. Why would the concrete poured in the front of the wall cause more force than the dirt that would be put back? My first thought was to unbolt the plywood and take it off of the outside, but didn't know if only having one side supported was a good idea. I don't think tarring over the plywood would keep it from eventually rotting, thus putting slack in the bolts.
 
I've been a civil engineering tech for 40 years.
The wall has been structurally compromised. What you're planing is like a band aide. The plywood may not be strong enough. Remember you have the weight of the house too.
Concrete never really dries completely because it is porous which will absorb water from rain this could rot the plywood over time.

The blocks being bowed in is telling me the mortar holding the blocks together isn't doing so anymore. Plus most block walls are core filled to help with the strengthening of to wall and also may have rebar run in them before they pour in concrete to core fill them. The blocks that are use are not solid, that's why they are core filled also. The concrete core may have cracked also which will also make it weak.

If the repair isn't done right you could get a sag in the wall structure above it and if it's a two story house that puts even more weight on it. Plus you have the pressure from the ground on the outside pushing on it.

I know you are trying to save money and I don't blame you one bit.
This kind of work should be done by someone that has done this type of repair before.

Good luck!
Tom
Here's a couple of diagrams.
concrete_block_foundation.gif
dia-block-waterproofing-800.png
 
Last edited:
IMO, Sounds like you need to shore up the dwelling, dig it out and re-block it. A family member just had it done on around 24 foot of their front wall. Wasn't cheap but you'll pay to fix now or likely pay when you try to sell it.
 
Ah, Tom, this is exactly what I needed to hear. Note I didn't say I wanted to hear it.

My house looks exactly like the color picture, with the exception that the floor joists run across the house, not front to back. The beam labeled 1 would be the sides only.

You're right, I am trying to save money. I saw something online that said it would be 3-5000 to do this job. I think it will be double that. Of course I bought a tractor to do my digging, so there goes the savings. (But hey, I have a tractor!)

I'm going to call and get a couple estimates on this, and see where I stand. Might be the perfect opportunity to do something different with the front of the house.

Thanks to all for weighing in.
 
Don't forget to build a support wall to hold up the floor joists before you start to dig . It will also help to get the wall sag out.
 
I did structural repairs to single family homes for a few years. Get a contractor that has experience in this type of repair. There is a lot more to doing it right than just laying some new block!!!
 
you need to build a wall 2-3 feet back stacking the 2x4 or 2x6 under your floor joist to carry the existing load of the cracked wall if that's the way the joist run if not you have to still build wall to cary the load fisrt . then you can carfully dig your way down bracing the concreate wallwhere needed to get straightend back out a lot of drilling for re rod and re pour the wall will be up to your engeneer wish I was there don't spend a nickel to save a dime now . really not that big of job if the joist run on top of the sagging wall, get a new 1 built quick you keep pressure off the concreate wall make sure there is a 1 foot gunderit to hold the house up then go digging in the outside carefully not to put inward pressure on the concreate wall. gl a year with out a toy beats a weekend in a rainstorm or worse your whole shelter caving in
 
As a bricklayer i've done several basement wall underpinning repairs. The best way to handle that is to dig out in front of the wall. A 2 ft bucket is perfect. Get down to the footer. Knockout every 4th or 5th block on the top coarse. Then run a 12'- 6x6 through the holes. Catch the rim joist ,then catch the 6x6 about 3ft-4ft back with a screwjack or hydraulic jack and post. Then catch it again another 4ft inward, trying to put the post directly under a joist. Jack it up evenly. A 1/2 is perfect for the bricklayer, but you cant always get it. Tear it out, relay it. Parge it with portland cement, then tar it. Let it sit a day or two set it down, pull the beams lay the beam pocket block. Install new french drains, backfill with #57 round stone. IMO that's the best way.
If its just bowed an inch or less i've seen guys put anchors in the concrete floor say 6 in a 24ft wall with screw jacks on a 45 degree angle against a 4x4 placed verticaly against the wall. Jack the house up, remove the rim joist, push the wall back plumb or at least strait with the screw jacks. Then grout every cell of the block with concrete. After they dug out the out side of coarse. I've personally seen walls bowed 2" snap back in place. The only thing that i don't like in your situation is, it sounds like your wall has vertical cracks as well.
 
If you don't fix the drainage, you're wasting your time.
The water in the soil is really what's generating the lateral load. I agree with the post above as far as the French drains. If you have the elevation, drain from the footing out, if no elevation sump pump it.

I used 1" gravel and perforated pvc pipe (not that shitty convoluted crap) with high grade barrier fabric and my wall isn't restored but it doesn't move when it rains now.

Fyi, the moisture is what makes Concrete generate the lateral load. It's all about the slump.
 
Wow my head is just spinning now. Here I thought I had a simple fix that I could do myself. I'm glad I asked. I already know that if I screw anything up my insurance won't cover it. I've already asked. Gonna for sure call someone to come have a look. Maybe a couple someones.

Thanks again everyone.
 
You must log in or register to reply here.
-

Back
Top