Cracked new floor

[slowTA]

My 32x50 floor was poured in late May and now (5 months later) I've noticed a small crack forming. It's probably 6" long and hairline, for now! I'm not necessarily the type to panic over a minor crack.

HOWEVER... the crack starts and ends at saw cuts. One end of the saw cut is just inside an overhead door and the other saw cut is in the apron/sidewalk outside. I'm worried about moisture getting in the crack and freezing.

For reference the floor is 6" thick over 4" of gravel, 2" rigid foam insulation, 5/8" pex every 9" (but about 6" off the doorway), 1/2" rebar every 2'. The concrete crew saw cut then sealed the floor by the end of the day.

I know there are caulking type of concrete repair compounds I can use, and probably should use to fill the saw cuts since I've seen some crumbling near the edges. But is there anything specific I should look for when comparing them?

 

[ConCretin]

The purpose of your sawcut joints was to induce a shrinkage crack so you wouldn’t see them. The crack you see is just a continuation of the crack in the bottom of the cut. It’s too bad they didn’t finish the cut so you wouldn’t see the crack at all. Nothing to worry about. You could open it up and apply sealant but I’d just leave it be.

 

[hermetic]

wouldn't worry too much about that, so long as it doesnt get much worse, but it would be a good idea to stop any moisture ingress before winter. looks like it might be where the floor concrete goes over the foundation pour (if they were done seperately). It is very unlikely to be anythong other than a minor shrinkage crack. Keep an eye on it.

 

[Shiftless]

I’ve heard it said that there are 2 truths about a concrete slab...

1. It will crack

2. Nobody will steal it.

 

[Dagny]

Yeah don't look at it.

 

[slowTA]

Thanks, I'm only worried about keeping moisture out of the crack before the first freeze since, as you can see, some of the crack is wet with rain.

 

[TheEquineFencer]

OMG! ITS GOING TO MAKE THE HOUSE FALL OFF!

Seriously, don't worry about it, smear something over/in it to deal/cover it and you'll not notice it when you walk past and stare at it.