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I'm converting my attached garage to a living space. The floor is graded and so will need to be raised (likely via putting an osb subfloor on top of it).

Current garage slab has contraction joints cut in the middle, and a fiber filled expansion joint around the outer edge.

Is there anything special I need to do to seal, fill, cover, etc, these joints, before they are permanently covered with new flooring? Or just leave them as is?

My gut tells me they need to be left as is, since their function is critical to protecting the slab, but just want to make sure there isn't some preemptive measure I need to take before they become difficult (albeit not impossible) to access.

The Shoe Shiner
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Those interior control joints don't require any special treatment. They're there as a structural version of an electrical fuse. The weakened lines allow hidden cracking to relieve stresses that would otherwise crack the slab in irregular patterns for everybody to see. Standard practice is for rebar to bridge the control joints so that no differential settlement occurs across the cracks.

The perimeter expansion joint isolates the slab from the structure. If the space was climate controlled when the slab was placed, then it might have been placed without the expansion joint. It shouldn't negatively impact anything so long as the joint filler isn't sticking up all. Even sticking up, your floor system might work around it without any problem.

popham
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