Tying in new slab to ICF

[69charged]

Hello all. I am looking to start prepping for a side slab and front apron on my garage. I am wondering about tying into the existing floor or not. I see some drill holes in the side for rebar to tie the two together and others separate them and put expansion material in between. I’m in Canada so there are freeze/thaw cycles if that makes a difference. I’m looking to pour a slab beside my garage and around the back as a side walk. Then an apron out front.
What’s the play on this one?

On the side you can see it’s ICF blocks and then the slab was poured inside. Do I rebar the 2 together?



For the front, same questions.
And should the apron and side all be poured as one, then saw cut afterwards or 2 slabs with an expansion joint or something?
Thanks
Clarence

 

[wssix99]

No. You want to put an expansion joint between the two and let the outdoor slab float. If tied into the foundation, the slabs will move differentially and build up stress.

Before you pour outside, you'll also need to grind down the protrusions from your interior slab so there is a smooth surface and the two slabs can slip past each other.

 

[Firebrick43]

Let them float.

 

[TurnipTruck]

At my last shop I doweled the apron to the shop slab, mostly because I was worried about shearing the pex I ran as a de-icing circuit. As soon as the first hard frost hit, I noticed concentric cracks every foot radiating away from the building.
On my new shop I will do whatever the local professionals say, and it probably will not involve dowels.

 

[69charged]

Ok. Thanks guys.
So I will form them up, with the appropriate slope away, but what material do I put in between the 2? In my old house they put what looked like press board in between. But that was made in the 70's.
Also, I plan to run pipe in the slab for my downspouts. But am thinking of the spring time during the thaw and freeze cycles and it backing up. Any thoughts on a solution there? I've seen people around here use heat tape running the length of the pipe to keep it from freezing. Is there any other methods I'm not thinking of?
Thanks

 

[Firebrick43]

You really need to put some synthetic stucco over the exposed foam of the icf first

Every builder supply house usually has a pressed tarred paper expansion joint and a poly foam type. I would probably use the poly foam but it’s really not that important. Your just separating the two.

You could even use pvc trim board or similar.

 

[jake28]

I just went through this exact situation and debate. I ended up not doweling or tieing the apron into my slab. Concrete guys explained it was possible that if water got in underneath, the apron could heave and start pulling my interior slab around with it. They explained the better option is let the apron float, and design it in such a way that it’s retained and and well supported and has little room to pull away from the building.

 

[69charged]

I just went through this exact situation and debate. I ended up not doweling or towing the apron into my slab. Concrete guys explained it was possible that if water got in underneath, the apron could heave and start pulling my interior slab around with it. They explained the better option is let the apron float, and design it in such a way that it’s retained and and well supported and has little room to pull away from the building.

What did you use as your expansion material?