New house build...concrete basement question

[kybuck1]

Building a new house now with basement. We are at the drywall stage and I noticed today that the concrete basement has a crack that extends from one wall to the other. The builder says is showed up pre sawing the slab and it's not a big deal. Before we go finishing it I was hoping for some opinions, questions to ask, and solutions if necessary. Thanks

 

[WiscoHoundsman]

Hard to say but not likely a bid deal. Surprised they didn’t cut it before it cracked most are cut that day or the next.

 

[WV Mountaineer]

Should have been sawed the next day before cracking happened. If it was then dried too quick or the concrete froze. Assuming neither, it simply wasn’t sawed quick enough or didn’t have enough saw joints.


This is all assuming the pad was prepped properly for the soil requirements. And, the house is setting on a footer sized and constructed and poured correctly for your soil conditions. And, heaven forbid the house wasn’t built on a slab.


Only you know the answers to that.


It’s likely not a big structural deal. As long everything was done correctly. Non shrink grout will fill it up

 

[PineBrook413]

I've run my own contracting business for two decades. ALL slabs crack. If they saw them quick enough it still cracks it just cracks in the sawed joint. As long as the crack isn't separating apart and one side isn't lifting or something it will be fine. attach some pictures if you can.

 

[roadrunner]

This is all assuming the pad was prepped properly for the soil requirements. And, the house is setting on a footer sized and constructed and poured correctly for your soil conditions.

This.

I've run my own contracting business for two decades. ALL slabs crack. If they saw them quick enough it still cracks it just cracks in the sawed joint. As long as the crack isn't separating apart and one side isn't lifting or something it will be fine. attach some pictures if you can.

And this.

 

[Tony Trietch]

All concrete cracks, you just hope to cut it in time so that you decide where that crack happens.

 

[98XJRC]

You've heard it from everyone else here already, however all concrete slabs crack. The purpose of saw cutting them after they have begun to cure is to encourage the crack to happen in the saw cut so that it's less visible. Even if they had saw cut there is still a possibility the crack would occur outside of the saw cut.

 

[Agross]

Concrete does two things. It gets hard, and it cracks. You can put control joints all over and still have a crack elsewhere sometimes. Typically it likes to crack off corners or posts or plumbing. Don’t know what kind of soil yer in or how wet the area, but as long as it’s tiled correctly you shouldn’t have anything to worry about.

 

[KurtR]

taxes death and concrete cracking three things that are guaranteed in life

 

[Brooks]

About 25 years ago I had a 48x 64 foot concret floor poured by a concrete company. They came in and put down some modified gravel, tamped it, put in rebar and some wire then poured the floor. To this day that floor looks great and I have never noticed any cracks. About 10 years ago a friend had a concrete floor poured for his new house. A couple guys who told him they were concrete men poured the floor in the rain, didn’t use any rebar or wire, they were big on the fiberglass mixed in the concrete. That floor started to crack and never stopped. Today the cracks are about an inch high and a half inch wide.

 

[hunterjmj]

I poured a 30x40 floor in my shop last fall over 12" or so of compacted gravel and rebar on 24" centers. I rented a saw and cut joints 2 days after and so far I haven't had a crack. Put a French drain behind the shop where there is a possibility of water collecting. I'm sure it'll crack sometime down the road but did what I could to have a solid base.

 

[stanginthe11s]

concrete doesn't always crack. it depends on how the slab is poured and what mix was used as well as how it was cured/treated after pour. is this basement above ground or below? how did you make it to drywall without seeing a crack? is this crack in the slab or the wall? are we talking spider crack or real crack? how long has the foundation been sitting? if this is an old foundation then the crack is probably fine, and you can fill it. if you're working on a new foundation then you could have a problem later. cracks don't get better, as the house settles and shifts it can grow. there are a few questions that can be answered by pics and me personally, I wouldn't continue finishing the house till I know it's safe and I'm happy with the final product. I always ask people " do you want it fast, or do you want it right because you'll never get both".

 

[Drenalin]

Post a picture of the crack with something beside it for scale. You're most likely going to have cracks outside of the control joints somewhere, and most are not a big deal (i.e., not structural).

 

[WCB]

Used to do floor covering. Don't think I ever saw a basement or really any other large pour without some sort of cracking. But without seeing it hard to determine.

 

[Beendare]

Oh man, where to start on concrete.
A lot of Concrete guys don’t know that adding water to the mix which makes it easier to work with can weaken the mix up to 20% right out of the truck.

Re your crack; many possibles…but the key here is to make sure the back aide of that wall is completely waterproofed with a 2 part system and has gravel and drainage So you don’t get water coming through that crack.

 

[TSAMP]

About 25 years ago I had a 48x 64 foot concret floor poured by a concrete company. They came in and put down some modified gravel, tamped it, put in rebar and some wire then poured the floor. To this day that floor looks great and I have never noticed any cracks. About 10 years ago a friend had a concrete floor poured for his new house. A couple guys who told him they were concrete men poured the floor in the rain, didn’t use any rebar or wire, they were big on the fiberglass mixed in the concrete. That floor started to crack and never stopped. Today the cracks are about an inch high and a half inch wide.

"Slab on grade" is the buzzword around no rebar, its a thing i guess. I had a patio done last summer and the gentlemen tried that on me. He also assured me the pea gravel that was down beneath the original deck would be sufficient for substrate. We butted heads abit in this process and admittedly I did not due my due diligence when we wrote up a contract so I didn't have much to go on besides my novice opinion to his professional one. (Union rep in the concrete field)

I made 3 phone calls to people I trust that also work in concrete and all 3 said to use rebar or wire paneling.

The day before the pour I went out and got wire paneling and he put it in.


OP:
I assume your worried about the basement leaking. How's your drain and tile work beneath the foundation? How's the landscaping around the exterior? Nows the time to get it "waterproofed" if you want to go that route. No idea how those treatments perfor. Though.

 

[KurtR]

"Slab on grade" is the buzzword around no rebar, its a thing i guess. I had a patio done last summer and the gentlemen tried that on me. He also assured me the pea gravel that was down beneath the original deck would be sufficient for substrate. We butted heads abit in this process and admittedly I did not due my due diligence when we wrote up a contract so I didn't have much to go on besides my novice opinion to his professional one. (Union rep in the concrete field)

I made 3 phone calls to people I trust that also work in concrete and all 3 said to use rebar or wire paneling.

The day before the pour I went out and got wire paneling and he put it in.


OP:
I assume your worried about the basement leaking. How's your drain and tile work beneath the foundation? How's the landscaping around the exterior? Nows the time to get it "waterproofed" if you want to go that route. No idea how those treatments perfor. Though.

I will bet you a million dollars that wire mesh is sitting on the bottom of the concrete not doing much. It gets stepped on while pouring the mud and always ends up there. rebar on chairs

 

[MuleyFever]

taxes death and concrete cracking three things that are guaranteed in life

I once worked for a prefab garage builder. They always said 2 things they could guarantee are that the concrete will crack and no one will steal it.

 

[Drenalin]

"Slab on grade" is the buzzword around no rebar, its a thing i guess.

A slab on grade means the concrete slab sits on the ground, as opposed to an elevated slab or a slab on deck. It doesn't have to do with whether or not it's reinforced.

 

[TSAMP]

I will bet you a million dollars that wire mesh is sitting on the bottom of the concrete not doing much. It gets stepped on while pouring the mud and always ends up there. rebar on chairs

It's funny you mention that because I pointed it out and he went in and put it on chairs.

The slab on grade makes sense, I incorrectly assumed it also meant no reinforcement when it wasn't Intended too.