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· Concrete & Masonry
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I see you are in Canada. Does that existing slab have adequate footing to the frost line and to support a garage built on it?
More than likely, it's a "floating slab", which is allowed by code in most of the US, as well as much of Canada, at least from what I can tell.


Every slab would ideally have a curb around the perimeter to keep the non-treated lumber at least 6" above the grade/ground........
 

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Discussion Starter · #5 ·
jomama45 is right - it's a floating slab, built up to and graded to 6" from the ground. I want to add the curb because the garage will be heated so I'm hoping for easier cleanup.

Since I would be adding this on top of the slab, will the "seam" between the existing concrete and the new curb be a weak spot for water to get in and eat away over the years?
 

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its called a ' cold joint ' & yes, it will be a weak spot for water to get in UNLESS you coat the exterior w/suitable waterproofing compound such as sonneborn's sonolastic or comparable product,,, NOT avail in apron/vest stores however they do have roofing cements
 

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You are adding the curb because in a previous post you admitted to pouring the slab with no curb. Cmon now, fess up. You can, and should add a level curb If it were me, I would hammer drill holes around the perimeter about every three feet to receive No 4 (1/2") rebar that sticks up about 7 inches. Form by Riping 2 x 12 to the slope of your floor so the top is LEVEL. Make the curb about 8 inches wide. Have someone make up a Z metal pan that has a 2 inch upturned lip inside, goes across under the curb, and turns down the outside of the slab about 2.5 inches with a drip. cut holes for the rebar and install pan by setting in urethane sealant NP1 is good, as is Bostic Chem calk 900. Ring rebar. Set that pan working fro low to high. Door to back of garage.
Put skewback on top of form to form 45 at top. pour curb with 3400 PSI concrete, and tap all around with hammer to remove honeycombs. Trowel top smooth. Use redhead anchors to secure PT sole plate over termite shield.
 

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Discussion Starter · #9 ·
I bought a spec house, not much say when the work was already done. If I could have done things differently, I would have gone with a much larger pad than 20x22 and had the curb integrated. Thanks for the detailed reply.
 
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