I appreciate whatever someone can provide here.
Although I hired a foundation contractor to resolve the issue, he kept going off on tangents (@$75/hr) without addressing the issue. After $5K and no drawings to detail the issue, I had to let him go take someone else for a ride.
I am adding a deck to the back of the stepson’s house. Below the deck, the space will be completely enclosed by a CMU wall sitting upon a 8″ high x 20″ wide footing (normal for the area, somewhat oversized for the load). The CMU wall will be veneered with a split face 4″ thick concrete block.
The difficulty comes to where this footing/wall meets the existing house’s foundation/footing.
Because we’re on clean virgin sand, the BI says no footing drains are necessary as well as he only wants the footing bottom to be 24″ below grade. West coast of Michigan.
Our excavation has exposed the existing footers – which are 8″ high.
Finish grade will be 6″ above the existing footers. Which translates into the top of the new footings to be 2″ below the bottom of the existing ones.
There will only be two points of intersection with the existing footers. The beginning and end points. Both coming out at 90 degrees to the existing.
The detail I need must show how the two interact. Do I underpin the existing with the new? Or simply abutt? Do I need a buildup at the point of intersection so the new actually supports the old, or let it float?
The CMU wall itself will abutt the existing poured ceement foundation. I’m assuming I will need to epoxy a few pins into the existing at select CMU layers.
The deck load itself will need to be built to hold 40#/sq ft.
The new foundation contractor sees no difficulty with the project, he just wants to see the detail to build to. I’m under a time crunch (thanks to the first brainiac), backing up the other trades involved.
Anyone got a book drawing or other sketch showing how this is commonly done?
To complicate matters, the Alienware ‘puter that I run Chief Archy on is in the shop confounding the ‘puter fixers. I can’t get that back til next week, so I’m doing this by hand…
As far as freeze issues, after the footing/CMU wall is in place, I plan on frost protecting the existing footers with 24″ of 2″ polystyrene placed vertically along side of the old footing within the new structure, coupled with at least 2″ of sprayed in place foam on the inside of the CMU wall. The deck will be solid thin decorative concrete bult to the specifications detailed in:
http://www.miracote.com/index.php?href=download Page down to the Miraflex II Decking System, code MIR 120.
And constructed to the ICC-ES ESR-1714 procedures. Thus being completely waterproof, weather resistant, and a class A fire rating. Underside of the deck will also be fully insulated, thus creating an extension of the basement’s insulated envelope. All has been approved by the BI. He, too, wants to see the detail needed before allowing the building permit to be finalized.
Can someone be my hero?
Edited 8/10/2006 8:16 pm ET by peteshlagor
Replies
I am in Michigan too, the last time I had to tie into a foundation I had to put 1/2" rebar pins into the existing footing 3 total into each tie in with epoxy.
I had to dig underneath the existing footing 8" and pour a pad along with the new footings. The pad was 3' by 3' by 8" deep.
I can't believe you can do 24" below grade, it's 42" I thought. At least around here.
Edit: wear gloves when playing with epoxy, don't want the hands to be like 80 grit sand paper. :)
What's wrong with me? I could ask you the exact same thing.
Edited 8/10/2006 8:28 pm ET by Stilletto
42" is what I was weaned on also.
But these are the Lake Michigan sand dunes. Pure sand, all the way down to China. Drains like a clean coffee filter.
It was the BI that said he'd allow the 24". I ain't gonna quibble with him.
I wouldn't argue with him either. Less digging is a good thing. What's wrong with me? I could ask you the exact same thing.
jutt butt up to it. epoxy a couple pins in the cmu to hold the wall