Ideas for the repair of faulty concrete work

[dlu]

I need some advice. Over the summer we had a concrete contractor come in to replace the floor in the carport that became a garage that became my shop. The space is about 20' x 20' and there was a slope of about 6.5" over that distance. The carport slab extended under the walls of the garage, so the contractor proposed to support the shop structure, remove the slab, and pour a new foundation. Since they claimed that they found rot in the plates of the side walls, they were going to remove about a foot off the bottom of each wall.

What they actually ended up doing was to prop up the structure and build forms about 4" inside of the walls. Apparently they thought that the concrete would fill the forms well enough to provide support and a weather / critter seal where the walls met the foundation. At least I guess that is what they were thinking…

When they built the forms they didn't bother to check that the wall was still plumb. Not surprisingly it was not, and it now needs to move about 1.5" towards the outside on one end. That will put the wall (framed in 2x4s) off the foundation to the outside. At the other end of the wall, where it was attached to the house, the wall is still plumb. There are also many places where the forms did not fill, so there are large gaps between the plate and the new foundation. The attached image is a section though the wall.

The contractor is eager to fix it (and get their final payment), I'm wondering if there are good ways to fix this – other than tearing out the work and starting over. Is there some way to pour a patch on the outside of the wall?

 

[waho6o9]

I'd find someone that knows what they're doing.

Best of luck

 

[dlu]

I'd find someone that knows what they're doing.

Best of luck

That's proving to be a challenge. It's a bit of a seller's market for contractors around here and we've had a few folks come to look at it and then ghost us. Luck may be needed

I'm expecting them to propose some sort of repair (as opposed to ripping out their work and starting over), and I can imagine that there might be ways to do a credible repair – though concrete is not my medium of choice… So, I was hoping to get some input.

 

[denovo]

I'd grout the concrete voids (cutting/chipping away concrete to gain access) with a product like Sika 212.  I would then frame the wall with 2x6s on the footing overhanging it accordingly so that it's straight.  The existing 2x4 wall can be strapped to match if required. 

 

[Peter Kelly]

Not sure if your inspector is going to go for this but it'd be relatively straight-forward to install.

 

[cblanton42]

    I'm a contractor in Tacoma-ish, give me a call today and maybe I can help you figure out a solution.  Mistakes happen, but this  sounds more like incompetence to me.  Charles Blanton  CB's Home Services  253 350 5515 

 

[Rob Z]

Given the amount of work to get this "right' , both structurally and appearance wise, I think it's easiest, fastest and best to tear out this mess and redo it.  It's not your problem to solve and certainly you shouldn't be stuck with a nagging feeling that some patching method might not last for you as well as if you got a solid concrete wall in the first place.

This same issue happened to us for a house we were having built, although the amount that the wall was off the foundation was far worse than your situation.  The builder went through all kinds of ridiculous steps to try and correct the mess with all sorts of cobbled "solutions"  and in the end we got our money back and found another house.

 

[dlu]

Given the amount of work to get this "right' , both structurally and appearance wise, I think it's easiest, fastest and best to tear out this mess and redo it.  It's not your problem to solve and certainly you shouldn't be stuck with a nagging feeling that some patching method might not last for you as well as if you got a solid concrete wall in the first place.

I've been stewing about this, my inner perfectionist wants to have the contractor to do that – but I'm not sure they have the skills / knowledge to do that. Plus the time & hassle seems like a bid downside to that approach. I think I could live with a well done fix. I just wish it was an "honest" mistake, this feels like a case of getting caught trying to slide with a shoddy job.

I'm liking the ideas of attaching a metal or pressure treated "flange" to support the wall, or reframing with 2x6 lumber.

 

[Cheese]

If this were my project, I'd start with placing a wood/metal form out where you need it and then angle it back to meet the part of the wall that's square. This form would go all the way down to the footing depth and you'd tie into the footing with rebar epoxied into the existing footing/floor. As the newly poured concrete gets thinner & thinner it's obvious that you can no longer use the rebar. At that point (probably around 3/4"-1/2" thick) I'd take a RA grinder with a tuck pointing blade and cut a series of longitudinal grooves in the existing footing so that when you pour the new concrete, it will key/lock into the old footing/slab.

So, once the new concrete is poured, you will have a long wedge of concrete 1 1/2" thick tapering to zero and the concrete will be the full depth of the footing and be attached to the footing with rebar and "keying"  grooves. After that slide the front of the garage wall over 1 1/2", straighten the entire length of the wall and secure with concrete fasteners and epoxy.

The unanswered question is how is the existing wall attached to the concrete riser, as that connection will need to be broken when you move the wall over 1 1/2". And the entire length of the garage wall must be able to move over some distance other wise there will be a kink somewhere and that would look ugly.

 

[woodferret]

I'm just a mechanical engineer, but I don't think a structural engineer would appreciate the vertical construction cold joint on a foundation wall if they reform and patch it (which is what I assume they'd do).  Gut feeling tells me that'd just slough off as it shears at the joint when under load unless it was properly barred or keyed, but I'm guessing it's pretty hard by now.

 

[BMH]

Hold off on the final payment and get a structural engineer to evaluate the problem and offer solutions. Then you can talk to the contractor.

 

[Bob D.]

^^^ this

 

[squall_line]

Did the work require any sort of permit?  If so, I would have no problems having the building inspector make the call on what constitutes a "proper" fix for this.  Assuming the contractor wants to keep working in the area, they'd comply with an inspector rather quickly.  Or, as BMH said, a structural engineer would probably give a definitive answer pretty quickly, although you may have to come to an agreement on splitting the cost.  The thing about the engineer is that they'll not only provide their assessment, but they'll charge again for the final inspection to make sure it's done to spec.

I wonder if you proposed splitting the cost of a structural engineer if the contractor would more readily agree to just tear it out and do it right, rather than pay the engineering fees (which would likely be a lot more expensive).

The right thing to do isn't always what someone wants to do of their own free will.  Get it done right and avoid the myriad headaches that come down the road with having to fix it again, explain it to a prospective buyer, etc.

 

[dlu]

Hold off on the final payment and get a structural engineer to evaluate the problem and offer solutions. Then you can talk to the contractor.

We've held off on the final payment.

Any suggestions on how to find a structural engineer? I'm assuming that there must be specializations in the field and that some folks would be more willing to consult on a small project than others.

 

[DeformedTree]

do a search on google maps for structural engineer, you will probably get a few hits for some businesses, or independent contractor types who do such work.  Your building department might have names, but also may not want to give them out so they are seen as giving work to people they know, etc.

I think you will either be tearing it out, or at the very least, the garage will need to be lifted again, they may be able to just form around what they did and just make the whole thing wider/taller.  I also don't know how square your garage was to start with.  Maybe it was out and they followed what was there, etc.

I think folks here have given some good suggestions. It's also better to have the garage over hang the concrete than the other way around, then you have to worry about water/rot issues over time.

 

[Peter Kelly]

Any suggestions on how to find a structural engineer? I'm assuming that there must be specializations in the field and that some folks would be more willing to consult on a small project than others.

https://www.aia.org/firm-directory

 

[jimbo51]

I am having difficulty sorting out some complicated wood joints. Anybody have a favorite concrete construction site I could visit for some guidance?

 

[Alanbach]

I may be a dummy or missing something but what about building a temporary support wall (if they haven’t already) and cutting the top plate loose and moving the top of that wall in the inch and a half to make the wall plumb. They would probably have to redo the soffit on that side but it might be easier than redoing the foundation. ??? Just spit balling.

 

[dlu]

I may be a dummy or missing something but what about building a temporary support wall (if they haven’t already) and cutting the top plate loose and moving the top of that wall in the inch and a half to make the wall plumb. They would probably have to redo the soffit on that side but it might be easier than redoing the foundation. ??? Just spit balling.

That's a really interesting idea...

I'm not sure it will be possible, the original structure was a carport built with 4x8 posts and beams supporting the roof, but I'm definitely going to give it some thought. Thanks.