Anyone here knowledgeable in Construction?

Wouldn't surprise me Critter if they have it less than that. I need to get settled in so I can build one of these or similar:
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Man, I hope so. I will prob call him Monday anyway and see what he says. You guys know my nerves are shot, right? If it cracks with no car in it how will it do with a C sitting on it?

Had similar cracks in the garage floor of my new house. 30 Michigan winters later still there. No change or new cracks.
As Detmatt said, that saw-cut or control joint did just what it is designed to do.
 
i don't understand what you guys mean by saying the joint did exactly what it is supp to do. Can you elaborate?
 
i don't understand what you guys mean by saying the joint did exactly what it is supp to do. Can you elaborate?

The saw cut was done to give it a controlled crack, instead of one running zigzag all over the place.
 
The old saying with concrete is not will it crack, but when. The saw cuts give it a primary where.
 
I bulit my garage in '99. I got a pro to pour the concrete footer. No concrete floor, just gravel. After he poured the footer, he told me that I might get some cracking, but that because of the rebar it wouldn't break apart. Within a year two cracks developed. I wasn't too happy to see them, but that was 2000 and now, seventeen years later, it's still just those same two cracks and you have to actually be looking for them to see them.
 
Mark, Matt and the others are correct from the little I know... the crack is right where it belongs and expected on a slab that big, which is why the relief cut was made. It may bring you some peace of mind if you have a copy of the blueprints for the house. Permitting would have required the footing to be detailed. If you still feel nervous, in the spring you could dig down at the outside wall where the crack is and see if it transferred down to the poured footer in this picture. I bet you have nothing to worry about.
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Code would require the above footing to go below the frost line.
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I don't see any rebar here... did they use fiberglass reinforced? If so it's good stuff and what my friend with the concrete business recommended for me.
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That joint is doing exactly what it should. My pour was about 18x40 and I was told it would be better to cut the relief to control where the crack formed. I waited too long... did the block myself and it took forever. Mine cracked right where we had decided the joint should go and was kinda straight. My friend told me not to worry about it, it was done cracking and I could membrane over the area to keep it from cracking any tile I put down. I haven't made as far as tile yet.

FWIW, my house was built in 1975. The original build garage has a man door at the front wall where the slab is raised about 8 inches. Due to the opening for the door and the settling of the house, I have a crack in the floor slab of the garage making a triangle with the doorway. My exterior walls are block, and the crack in the mortar joints where they had expanded slightly (less than 1/4 inch) went from the top of the door frame to the top of the wall. I repaired this with concrete epoxy, the hard stuff I was using to tie my rebar to the existing slab... the building inspector saw no problem with my crack repair or the structure of the house. I have a couple years now that 2 Imperials live in that garage with no change in the crack in the floor and no change in the crack I filled in the wall.
 
Two things guaranteed in life, death and concrete will crack. As others have pointed out it is on the control joint, which is why that is there to direct cracks through that joint and not down the center of the slab.

Don't believe Mark that corners were cut. The dwelling needs to be built to engineered plans. The plans need to be followed, it is up to the builder and the building inspector to make certain things are correct.

Knowing you I'm sure you did your homework before hiring the GC. Reputation , references, photos were all probably considered before you hired him. He likely has been in the business many years and wouldn't be if he cuts corners.
True, I don't see remesh in the slab either but that may not have been required. If they used fiber in the concrete or if they put the mesh in after the photo was taken, we don't know. That however doesn't keep concrete from cracking remesh or rebar will help keep it from separating but it not cracking.

I would glance at it now and then but wouldn't be too pissed off, maybe annoyed
 
That diagonal crack at the corners from the big door to side wall is a guarantee in our frost cycles. I just ran some sealer in the crack to keep water from washing out the substrate.
 
Not much to add to what has been said... new concrete is liable to crack. A floor slab that is 4” thick, which a garage floor needs to be at minimum, must have expansion joints - cuts - at 24x24 foot (8x8 meters) intervals, maximum.

Now it seems, that there is no elastic joint between the perimeter block and the floor. There should be: some non-porous matting, like 1/8” PU-matting, or equivalent. There is none: that is why the crack expanded up the block. It definitely should not have done so, even though that seems to be a cosmetic fault only.
 
Not sure I agree with all of that. While I agree about expansion joint I disagree that is why the block cracked there. Since the floor has a crack and the block shares the same fracture location i don't believe that's from the slab expanding but rather minimal vertical movement
 
Not sure I agree with all of that. While I agree about expansion joint I disagree that is why the block cracked there. Since the floor has a crack and the block shares the same fracture location i don't believe that's from the slab expanding but rather minimal vertical movement

Omission of the elastic joint is a clear construction fault. No two words about that. It is exactly because the crack continues pretty much straight up the wall - it does not seeem to go sideways - I believe it’s the tension in the floor slab which caused that crack. Had the foundations given in even just a bit, there would be a horizontal crack. But there seems to be none.
 
Fiber reinforced cement/concrete (crazy concrete guy story Ive mentioned before - cement you use a trowel, concrete a jack hammer :) ) cracks as well. It all cracks. The foundation wall is not really tall...I don't see much of a load on it...I wouldn't worry myself with it. A vapor barrier before pouring the concrete is a nice touch, an expansion matting would be great, but it will still crack. Maybe not today.

If down the road you see drywall cracking and splitting, and not at the tape joints, then you have a problem. This one is no big deal.
 
my parents built a garage in 1988 that cracked just as yours did within 2 weeks of being built. it will be 30 years next summer since its construction and it has never gotten any worse.
 
Omission of the elastic joint is a clear construction fault. No two words about that. It is exactly because the crack continues pretty much straight up the wall - it does not seeem to go sideways - I believe it’s the tension in the floor slab which caused that crack. Had the foundations given in even just a bit, there would be a horizontal crack. But there seems to be none.

So you think it's pushing and that's where it cracked?
 
Concrete slabs can shrink as much as 1/2" per 100' which is why expansion joints are required otherwise the shrink stress will tear the pad apart. Normally you would set your footings and pour the slab over top of the footing right to the outer edge, then after allowing some cure time, the block wall would be built on top. Alternately if the slab is poured after the block wall is built, the mason would fill the first course of block with concrete and he would use tie strips to anchor the wall to the slab.
In any case your little cracks are normal and after a few months fill them if they bug you. Note you can stop a crack from growing by drilling a hole at the end so that the stress causing the crack loses focus.
 
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