Crack in the hearth slab

[dmun]

Re: Crack in the hearth slab

Almost all concrete cracks, because it shrinks when it dries, and successful slab pours depend upon introducing artificial cracks, in the form of expansion strips. These shouldn't be necessary on such a small slab, and indeed it looks like your hairline crack is not structural at all, just the surface drying slightly faster than the underlying layers.

Here's a site that talks about the various forms of cracking in concrete.

[christo]

Re: Crack in the hearth slab

Sorry to hear that.

How thick is your support slab and where did you position the rebar within it?

How much do you use your under oven storage? Would a center support column interfere much with how you use it? I would go ahead and shim it up with a 2x6 and a wedge underneath (just to snug it up by hand - don't drive it home with a hammer) while you wait for the experts chime in....

Christo

[Frances]

Hmmm, yesterday I discovered a crack in my hearth...

Just above the entrance. What do you think, can I do anything about it at this stage? Do I need to? It's reinforced with rebar etc.