Oh my, very long evening! Measured the basement that the concrete company has poured for me … and it’s 4ft too short. I’ve got radiant tubing all laid out down there, that is a whole ‘nother issue. Question I’m trying to figure out, is I don’t know much about concrete.

I’m pretty set on asking them to knock out the wrong wall, and extend the footers and basements walls out to the appropriate dimensions. What should I be looking for to make sure this seam between the old (2weeks ago) and new work does not split, crack, leak … or, any number of bad things I have going through my head. They had quite a bit of reinforcement rebar in the existing wall, that I was pretty happy with … now I think my brother told me, they’ll probably drill lags into the stub after the bad wall is torn down? Will that be enough reinforcement over time. Or, am I looking at having problems 20yrs down the road?

Please help … I’m supposed to start giving them my solutions by this morning.

Thanks, Neal

I'm not an expert but did work on an addition once where we added a slab to the existing one. We rented a heavy duty hammer drill, put in 1/2" holes 6" deep into the old slab. Then drove in 18" long rebar with a hand sledge hammer. Wired the rebar for the new addition pour onto those. There should be a local code on that. Check the website for the city or county building inspection department.

Does that sound right to everyone? I really have no idea on doing foundation work.

Thanks, Neal

If I understand this correctly, you need to take out a wall and extend the
wall, footer and floor 4 ft.

If so, take the wall out and leave the footer it is built on. This will shore up
the new and old floor. No need for rebar or expansion joint or anything.

You will need a new footer 4 ft out for the new wall. The shelf on that
new footer will support the newer floor.

Yep, rebar into the existing concrete will keep the joint sound for many years. I did that last year when I had a slab poured off to the side of my driveway. Drive over it quite a bit, it's not moving.

I'm not an expert but did work on an addition once where we added a slab to the existing one. We rented a heavy duty hammer drill, put in 1/2" holes 6" deep into the old slab. Then drove in 18" long rebar with a hand sledge hammer. Wired the rebar for the new addition pour onto those. There should be a local code on that. Check the website for the city or county building inspection department.

I don't think there is a need to drive the rebar dowels into the existing slab with a sledge hammer (risk cracking the existing slab...).

Just drill the holes, and epoxy bond the dowels in, then later tie these bars to the rest of the new rebar. These dowels should help keep reduce any differential settlement issues.

Not sure what is available to help seal cold joints between the two pieces... But the guys pouring the concrete should have an idea of what's available to seal the joint...

Not sure i can answer your question on what to do but whos fault was it that it was 4 feet short?!?! Is it yours or some contractors? If its a contractors and it was mine, i would have a VERY hard time not making them rip out the entire floor and starting over on his dime not yours. Then you wouldn thave these worries.

Andy

I had a similar situation when I built my last house 10 years ago however it was on the foundation for the attached garage. They cut the foundation walls (floor was not poured yet) , drilled and doweled (epoxied into the existing concrete) and extended the front of the garage 2 feet.

This never budged in 10 + years however it wasn't a basement and was only carring the garage load, not a house. Back then, the building inspector said if it was the foundation under the actual "house" portion of the site, he would need signoff from a structural engineer but since it was a garage, no big deal.

Hi here is my quick 2 cents... first if you have the time get a structural engineer to review the problem... if you have to make a decision, this is what i would do: remove the wall that is in the wrong location and the associated footing, cut the other two walls back over the existing footing min. 24", drill and grout 3' #25 epoxy coated rebar 12" into existing wall at max 18" spacings (or whatever the spacing was for horizontal rebar in your current wall if more frequent than 18" -not likely though), drill and grout 2 top and bottomg - 3' #25 epoxy coated rebar 12" into existing footing, have them use a bonding agent between the new and old pour. Also the idea to cut back the 2 return walls a bit more off the current footing is so that the joint between the 2 walls is not over the same new joint in the footing...

actually just thought of this while i was typing, not ideal, but if you are o.k. with the basement size you could have them pile and pour a grade beam to support the last 4' of your house... i would be worried about differential movement though between the house on a footing and the portion on piles... but this is how most house additions are constructed...

K, I read your post again, slowly, and now it sounds like you have poured
concrete walls on a footer. You have tubing for floor heat laid out and
your length on one end is 4 feet short.
There is no floor poured yet, correct?

You will need rebar or steel dowels in the walls that will be extended.
If you leave the existing footer, the floor will go right over it. A new footer
will be dug 4 feet out and the new wall poured on it.

If the walls are block, a good mason could weave new block into the
original wall.

Man, thanks for all the replies/help guys … Want to talk about 1 stressful event! Error was definitely on the contractor, we even went over already that he had the correct drawings … and just added a figure wrong. I’m not too malicious a person, so none of this is ever taken personally, and I really am going to try working with him as best as possible … though I’m not too thrilled with his response this afternoon

Yes, you did read the post right … I currently have poured basement walls over concrete footers. Underfloor insulation and radiant tubing/manifolds have been installed. No concrete floor slab has been poured yet. And the wall needs to move 4ft further out.

Believe me, I left my message with the building inspector prompt at 8AM this morning (haven’t heard back). Primary question for him is … Does he have the experience to protect me from future defects? If you do a room edition, you have to accept the risk of cracks/leaks occurring where the wall is joined … I planned this house large enough, to never want a room edition, and thus one continuous pour.

Yeah, I know it wouldn’t be a problem leaving the existing footer underneath of the wall to move … though I suspect when the wall comes out, chances are the footer will come with it. Since there was never a footer designed there, I don’t think it would cause an issue either way.

My biggest concern, is where the two footers must be joined and the corresponding walls. I do like the idea of setting part of the new footer/wall over top of the existing footer … I think I would feel better about the two not separating if it was put together that way (kinda like Lincoln Logs). Truth is, I am a Mech. Engineer … and can reason things that “make sense” … but I have no experience or training in Structural Engineering! What would be your guys call … should I consult a structural engineer before I agree to any terms? I’m wanting to talk to the building inspector and see what experience he has?

P.S. I’m trying not to fume today from my earlier conversation (hopefully just mis-understood) … but the comment that he didn’t want ME to have the expense of taking the radiant tubing out, hopefully was not implying my dime on any of this. I’ll work with him as best as possible, but it sure ain’t on my dime!

Please help … I’m supposed to start giving them my solutions by this morning.


And why in the world would you have to provide a solution? The contractor made a mistake, and it's his responsibility to tell you what he can do to make it right. Once he has suggested a way to correct the problem, ask an independent engineer or an inspector to review it to make sure it's a good way of solving the problem.

If you provide a solution, the responsibility will be yours. So if the floor starts cracking, they'll just say: "But that's what you told us to do!" I have seen many contractors using that little trick of the trade.

Let them tell you what can be done, and make sure that you get it documented for future reference (revised drawings, details, material specs etc) + an approval from the inspector. Even if it sure will be a headache to you, it shouldn't be your problem to come up with a solution or sharing the responsibility for it. And of course, all additional costs such as extra excavation and foundation work, redoing the radiant heat etc. should be on him as well.

pay a few bucks and get an structural engineer in there... being a mechanical you wouldn't want to get advice based on guess work, and you know the liability will rest with the struct. engr. Did you have an engineer stamp your original foundation plans? give them a call...or any decent reputable firm for that matter...

concrete on concrete pours with a bonding agent are good... if you tried to seperate the concrete if would not fail at the bond line. also you will have cracks in your basement walls over time and this is expected and not considered failure... your damproofing on the outside will prevent any moisture from hitting the concrete...the rebar is to resist forces from hydrostatic pressure and soil backfill.. the footing is resting on undisturbed soil so the the assumption from a structural point of view is that is a bearing surface for the foundation wall.. it is not expected to span any distance (like a grade beam would) so any cracks there are relatively insignificant... look at it this way, your foundation and basement walls were poured seperately and there is a cold joint between them...theres no issue there...

good to hear your basement floor isnt poured!!... stand your ground and dont give the foundation guy any $$ until you get this resolved. also do NOT rely on your building inspector to provide any advice... they are not liable for any advice they give you...and unless that person has significant structural background take the advice with a bit of skepticism... like all the info you are getting here too...

i'm an architect and direct a planning dept that puts through about $100M a year in construction... my best advice again is to get an engineer to recommend a solution and pay the engr a few more bucks to inspect the remedial action so that they dont cut any corners... let us know how it goes...

Well, the follow up from last night.

Spoke with the building inspectors ... and they must see an approved modification drawing from a P.E. So that was good news. They admitted that they have general construction / remodeling drawings ... but nothing for a mod like this, nor the knowledge to advice it. I was glad that they were not going to try pushing their limits, and would support me on requiring an engineering drawing.

Spoke with the contractor (still not too sure about him) ... his initial reaction was, "OH you spoke with the county about this". Got more of the impression he thought this was our dirty little secret. Anyhow, he is to contact “his” engineer this morning. I’m going to have to let this one fly … as long as it comes with a P.E. approval. I doubt I would find a second opinion that something was dead-wrong, just might have been done differently. That’s the way engineering goes, more ways to skin a cat than you could imagine

I asked him to bring the modification drawings with him when we meet. I’ve at least enough experience to know what a P.E. stamp looks like, and will go over the approval with the county building inspectors myself.

I’m seriously reconsidering doing the radiant tubing mod’s myself. The contractor just does not seem to want to heed the advice I’ve gotten from some other radiant floor installers, and I’ve got other responsibilities coming on the house. I think I’m going to turn this over to let another contractor make the mods to the flooring.

Anyhow … thanks for all the advice. I’ve done a lot of housing projects over the year, but don’t do foundations!
Neal

Before agreeing to what his PE has suggested, perhaps actually give him a call and let him know your concerns... tell your contractor you want the PE on site and ask to be there at the same time... this contractor is going to find a PE that will give him the easiest solution... remember you dont have to accept it for what it is and running it past another PE for your peice of mind is worth it... realistically someone will might charge you $50 or $100 to review the solution... probably just glance at it and give you a "looks o.k." for free...

good luck, sounds like you'll get a good resolution...

ak