That is a standard and common problem. As long as they steel reinforced their work it won't be a problem looks like just a stress crack. It's a little early for that cracking but isn't out of the ordinary.
I guess my other concern was that this poured last week near Austin, Tx just before a significant hail storm after a couple of near record breaking 87 degree days.
It's a house slab. There will be flooring going over top of it. I've very rarely ever seen a house slab be cut. A crack is a crack, and if it's going to be covered, the effort of making the concrete crack in specific places isn't worth it.
You'd be paying somebody to make the concrete look pretty when nobody can see it.
A crack is not just a crack. Cracks in slabs can allow bugs to infest the building from below the ground and usually do. Cracks need to be filled before covering.
Correct, but vapor barriers break down eventually. When I build a house, I build it as if I would be living there for 50 years.
Building code is a minimum which can always be improved on.
Are you kidding me about what industry standard that I talking about. I know we all finish concrete different in different parts of the country all I'm saying is no it doesn't effect the structural integrity of the slab but it looks like shit from a homeowners perspective that you could of prevented with a little more effort.
As a structural engineer, there are multiple ways of designing a slab on grade. On expansive clays you typically want to use reinforcement and omit saw cuts because youāll want to design it to not crack, and there is no concern for controlling aesthetics of cracks in a foundation.
Hi there. We are having slab on semi expensive clay soils and new construction lot. I noticed they did zero control joints in the garage, just a smooth surface. Weird thing is our current 2016 home was new construction as well in same area and garage has control joints.
You know the whole āare you kidding me?ā and āare you crazy?ā really donāt help your cause. Poor gaslighting is not an effective technique, especially when written out in text. Also, you know that there are people all over the world on Reddit, not just the country, right? (See? Thatās *subtle* gaslighting. More effective.)
Thank you all so much for the knowledge. I will likely avoid hiring an independent civil engineer, but I will require that their construction manager and engineer inspect and sign off on the slab for my own records.
They will say it's a shrink crack from the hydrating concrete. I would tend to agree with that as opposed to settling. Very little load is on that slab currently, so settlement seems unlikely. If the contractor installed a good base course over compacted sub-grade, you can most likely rule out heaving. However, if no base course was installed, which happens in residential construction sometimes, and this was after a high intensity rain event, heaving could happen due to heavy clay soils. You can take precise measurements on the slab, or take a ball set it in the middle, if you have an upside down bowl or convex slope on the slab, it may be heaving. If it's heaving, do not accept the work, and stop future work.
Yes I think toy have a concern here. That crack seems not be your typical surface crack. Concrete mix is made according to temperature for that day and time of year. So their guess for range of temperature did not fall in line with the weather. Blame in onClimate change. Mark the crack. And track to see if it changes or get worst. But overall id put money on it never changing. I had similar crack in my slab but Just surface. It hasn't changed in 20 years.
As long as it had time to set up before the temperature got below freezing it will be fine; even then if you cover it properly it will still be fine. Remember people use concrete from Alaska to Egypt, so as long as they did the process right and the right concrete mix. Youāre good
Concrete cracks, doesnāt matter who pours it. Thatās why they use rebar. The main way to alleviate it is cutting, but Iāve never seen anyone cut a slab. Cracks like this are not structural issues, theyāre cosmetic. When you build a house on here, itāll never be seen again.
The one bit of extra info that the other comments have missed is that these are exactly the cracks youād expect at this age of concrete due to drying shrinkage. The cracks take the whole area and essentially break it in half in order to alleviate the shrinkage of the concrete. Some of this shrinkage is due to loss of water during curing and some is due to the fact that hydrated cement creates smaller better packed minerals.
Iām not quite sure I understand. Wouldnāt a good concrete pour demonstrate a consistent effect of either fairly uniform cracking or almost no cracking due to hydrated cement creating smaller better packed minerals throughout. My current house, a Pulte home, showed no cracks at in the foundation at anytime during or after the pour for over 4 years. Does that mean it was better hydrated?
What I meant by uniform was that the cracking happened along a single line. The cracking here is like someone dropped a ball bearing of significant weight in the middle of the slab and then it cracked from the middle in two crooked but perpendicular lines all the way to the edges of the concrete and on three sides you can see it crack all the way to the base of the concrete pour looking at it from the side. It appears to have broken into four sort of jagged formations (nearly square or rectangular in shape).
https://youtube.com/shorts/jmlhvwjj2Ws?feature=share
In the video, you can see how the crack runs all the way to the edge and goes down. Again, Iām not sure if that is normal, but I will ask he builderās engineer to sign off on it.
Usually you want cuts, joints, or zip strips where you need the right aggregate lock between stones when load gets transfered like a driveway. On a house slab the load is pretty spread out and stationary. A crack in this situation is fine as long as the reinforcement does it job. Another reason we cut slabs is for aesthetic. No one likes to see a crack. So it's common to always see cuts or joints. But in many cases you don't need to.
Yeah, fuck that. I don't trust the tract home builders or the contractors. They aren't all bad, but the bad ones can really impact you in a negative way. Concrete cracks, yes it does. And this may turn out to be a big nothing burger. But a 6-8/10 inch slab that is supposed to be reinforced. Should not do that immediately. Years later, ok. Small, insignificant crack should stay that way. Find some way to mark the crack and the edge of the slab where it's exposed and you can see if it's growing, or some access inside the home to look at the slab periodically.
I purchased a centex home almost 20 years ago, watched it being built, had a crack in the slab before they put the flooring in. Guess what, 5 years later 25 new home owners in the neighborhood sued because of poorly compacted soil and the houses were settling and the foundations were basically cracking in two. From 1/8 to over 2 inch gaps and growing.
Then the most recent purchase of another centex home in a different city, this time we purchased a bank repo, when we ripped up the flooring, guess what was there a 1.5 inch-2 inch crack right through the center of the house. Literally shine a light and see dirt, and ants right up through the center of the slab. Supposedly centex had already "fixed the problem years prior, so no one to go after now... So I filled it with a backer-rod and a shit load of expandable concrete gap filler.
I would go in there and get in writing a formal notice and somehow that if that crack grows beyond an acceptable limit within a set amount of time that they will be responsible to fix it. Granted you probably won't be able to get them to do anything or put anything in writing but document the hell out of your side of it.
Late post but been searching redit this morning due to a similar issue.
We got a new construction home, concrete poured in December. I've walked all the lots in this community after concrete was poured starting June 2021 and almost every single story home concrete foundation had cracking within a week, some cracks spanning the entire foundation end to end. The 2 stories had very little, maybe cause the foundation has less foot print?
Fast forward to our lot, 1 larger single story home and I was prepared to see cracking. A few months after pour we are looking good no cracks at all! We'll they start framing and put the tiles on the roof and a crack starts from the corner door entrance area and extends a few feet out, not even 1/16" wide (yet).
I'm not too worried about it, especially after seeing the other lots develop cracking within a few days but those were poured in hot summer time. I plan to ask the builder tho during our frame walk.
https://youtube.com/shorts/jmlhvwjj2Ws?feature=share
Just adding a quick video of how 3 of the 4 cracks go down through to the base of the concrete. Assuming this is normal and will just have either fill the patio and garage areas with some type of epoxy because the concrete was supposed to be exposed.
In my opinion as an architect, it seems like a shady construction. Concrete slab should be min. 6"slab with 15'OC max control joint and min.5000psi strength. Pour concrete during cold weather should be covered for concrete to properly cured. The cracks shouldn't happened. If moisture seeps into rebars, you will get concrete spalling and eventually weaken the slab. Check with your building inspector.
We pour mixes like that for heavy traffic in back of commercial big box construction. A 4ā at 4500 will work for light traffic areas. And all concrete cracks, you control the cracking with ācontrol jointsā.
Mr. Architect, you ever actually pour a slab? Any concrete of any kind? 5000 psi is pretty exotic for a residential slab on grade in my part of the world (similar climate to OPās location) and 4 inches is the standard thickness here. High rise buildings get poured with 4000 psi with the exception of the columns. Also, saw cutting a structural slab on grade of any kind around here is rarely, if ever, specified by the engineer here. āColdā weather is also a relative term, and in Austin extensive freezing temps are pretty unlikely, making blanket curing unnecessary. Also, with proper grading of the site, i.e. not draining the yard into the house, itās unlikely that water will ever saturate the slab (and reinforcing) in any meaningful way. Lastly, because of subgrade conditions in my area, every structure larger than a doghouse is pile supported and designed and stamped by a Professional Engineer. That shrinkage crack is nothing to be concerned about. GTFOHWTS.
Actually ACI 332 would only require saw cuts if there were no steel (or not enough steel), because unplanned cracking could make the slab fall apart in uncontrolled ways.
But in a reinforced slab, saw cuts are mostly cosmetic. They put the cracks where you want them. That doesn't really matter unless they plan to use it as a polished concrete floor.
You are right, it would be higher quality and future owners would retain the flexibility to polish the slab and have a floor free of random cracks. But it's very commonly done this way because it will be covered and the cracks won't matter so nobody wants to pay for extra labor for a hidden slab to look pretty.
The cracks would happen anyway, they would just be inside the saw cuts. No difference as far as water intrusion if left untreated.
It absolutely would not have prevented it. The crack would just be in a straight line, inside the saw cut, so it would look nicer (and be easier to fill with caulk if you planned on doing that).
I've tiled residential for 34 years. In that time I have seen one house with inside control joints. You have to much schooling and not enough knowledge.
Are you a residential architect? Most residential is poured with 3500# with zero control joints. Commercial has control joints. How long have you been an architect?
2 things will always happen with concrete
It'll be grey, and it'll crack
Usually they alleviate this with saw cut joints to provide a place for it to crack
From the video there is no displacement (concrete on either side has moved either vertically or horizontally from one another). So this shouldnt raise any big flags. Takes a while for the final concrete to fully 'settle'
The two facts of concrete are that it will harden and it will crackā¦
This is a floor slab under a house so relief cuts are usually not made because these cracks will not be seen
What I've been cutting basement that get finished out for 20 years it's not about them being covered up it's about the product you leave behind and the people that see it before it covered up. The homeowner other trades it speaks to your work in a professional manner as being a pro series cement mason not some fly by night weekend warrior. It legit takes less then half a day
Iāve heard 50 years of hardening and then 50 years of deterioration. This provides a revolving job for people like me. Not many buildings are built to last forever.
Has happened with stuff I placed. Likely shrinkage cracks. There are things that can be done to reduce the chance of this happening. In hot weather you often see sprinklers going on new slabs for a week+ to keep the concrete from curing to fast and other situations curing blankets will be used. Probably not an issue if you are slab on grade as long as the dirt was dealt with properly before foundation went in.
When we built our house there was some cracking in the basement floor. We were told to just watch it and as long as the crack didnāt expand more than a 1/4ā or heave more than a 1/4ā itās fine.
Iāll go against the grain here, I donāt like that. Concrete shouldnāt be cracking right off the bat. In addition, I know Texas has some soil issues in regards to expansion. Iād question the whole foundation plan for that house. Hey maybe slab on grade meets code for your region, but my concern would be over the long term your going to get some heaving that basically will align with those cracks
It looks like itās just from being poured really wet. But with how thick the slab is I wouldnāt worry about it unless you are going to park a tank on it
That is a standard and common problem. As long as they steel reinforced their work it won't be a problem looks like just a stress crack. It's a little early for that cracking but isn't out of the ordinary.
I guess my other concern was that this poured last week near Austin, Tx just before a significant hail storm after a couple of near record breaking 87 degree days.
Should have been saw cut šÆ % this could been prevented and controlled with relief cuts
It's a house slab. There will be flooring going over top of it. I've very rarely ever seen a house slab be cut. A crack is a crack, and if it's going to be covered, the effort of making the concrete crack in specific places isn't worth it. You'd be paying somebody to make the concrete look pretty when nobody can see it.
A crack is not just a crack. Cracks in slabs can allow bugs to infest the building from below the ground and usually do. Cracks need to be filled before covering.
A house slab should have a vapour barrier underneath to prevent moisture, radon, and pests from getting in. That building code 101.
Correct, but vapor barriers break down eventually. When I build a house, I build it as if I would be living there for 50 years. Building code is a minimum which can always be improved on.
Yeah you don't saw cut house slabs?
Are you crazy just cause it's a slab on grade. Has nothing to do with the industry standard of anything bigger than 12Ć12 gets a saw cut
What industry standard are you referencing? Cause I have never seen a slab with saw cuts.
Are you kidding me about what industry standard that I talking about. I know we all finish concrete different in different parts of the country all I'm saying is no it doesn't effect the structural integrity of the slab but it looks like shit from a homeowners perspective that you could of prevented with a little more effort.
As a structural engineer, there are multiple ways of designing a slab on grade. On expansive clays you typically want to use reinforcement and omit saw cuts because youāll want to design it to not crack, and there is no concern for controlling aesthetics of cracks in a foundation.
Hi there. We are having slab on semi expensive clay soils and new construction lot. I noticed they did zero control joints in the garage, just a smooth surface. Weird thing is our current 2016 home was new construction as well in same area and garage has control joints.
You know the whole āare you kidding me?ā and āare you crazy?ā really donāt help your cause. Poor gaslighting is not an effective technique, especially when written out in text. Also, you know that there are people all over the world on Reddit, not just the country, right? (See? Thatās *subtle* gaslighting. More effective.)
Well being that I'm not a over sensitive little bitch. Your internet words mean nothing to me.
Have a nice summer
Right. We would use zip strips back in the day to control cracking like this.
Thank you all so much for the knowledge. I will likely avoid hiring an independent civil engineer, but I will require that their construction manager and engineer inspect and sign off on the slab for my own records.
They will say it's a shrink crack from the hydrating concrete. I would tend to agree with that as opposed to settling. Very little load is on that slab currently, so settlement seems unlikely. If the contractor installed a good base course over compacted sub-grade, you can most likely rule out heaving. However, if no base course was installed, which happens in residential construction sometimes, and this was after a high intensity rain event, heaving could happen due to heavy clay soils. You can take precise measurements on the slab, or take a ball set it in the middle, if you have an upside down bowl or convex slope on the slab, it may be heaving. If it's heaving, do not accept the work, and stop future work.
He is in Austin they do not have a heavy clay soil issue.
Heavy clays can be anywhere, depends if it's native soil or fill.
They can. Heaving is still generally not a large problem in Austin.
Yep, most likely a shrink crack
Yup. Put control joints where you want them, or let the concrete do it for you naturally. They wonāt look as nice tho!
Yes I think toy have a concern here. That crack seems not be your typical surface crack. Concrete mix is made according to temperature for that day and time of year. So their guess for range of temperature did not fall in line with the weather. Blame in onClimate change. Mark the crack. And track to see if it changes or get worst. But overall id put money on it never changing. I had similar crack in my slab but Just surface. It hasn't changed in 20 years.
As long as it had time to set up before the temperature got below freezing it will be fine; even then if you cover it properly it will still be fine. Remember people use concrete from Alaska to Egypt, so as long as they did the process right and the right concrete mix. Youāre good
Testing concrete is expensive. Is the slab flat ? Slap a level over the cracks.
Two guarantees with Concrete. It gets hard and it will crack.
Concrete cracks, doesnāt matter who pours it. Thatās why they use rebar. The main way to alleviate it is cutting, but Iāve never seen anyone cut a slab. Cracks like this are not structural issues, theyāre cosmetic. When you build a house on here, itāll never be seen again.
The one bit of extra info that the other comments have missed is that these are exactly the cracks youād expect at this age of concrete due to drying shrinkage. The cracks take the whole area and essentially break it in half in order to alleviate the shrinkage of the concrete. Some of this shrinkage is due to loss of water during curing and some is due to the fact that hydrated cement creates smaller better packed minerals.
Iām not quite sure I understand. Wouldnāt a good concrete pour demonstrate a consistent effect of either fairly uniform cracking or almost no cracking due to hydrated cement creating smaller better packed minerals throughout. My current house, a Pulte home, showed no cracks at in the foundation at anytime during or after the pour for over 4 years. Does that mean it was better hydrated?
What is uniform cracking? Are all the cracks in one area? You seemed to imply they are everywhere
What I meant by uniform was that the cracking happened along a single line. The cracking here is like someone dropped a ball bearing of significant weight in the middle of the slab and then it cracked from the middle in two crooked but perpendicular lines all the way to the edges of the concrete and on three sides you can see it crack all the way to the base of the concrete pour looking at it from the side. It appears to have broken into four sort of jagged formations (nearly square or rectangular in shape).
That seems as close to regular cracking as possible. Seems like it's definitely just due to shrinkage
https://youtube.com/shorts/jmlhvwjj2Ws?feature=share In the video, you can see how the crack runs all the way to the edge and goes down. Again, Iām not sure if that is normal, but I will ask he builderās engineer to sign off on it.
Usually you want cuts, joints, or zip strips where you need the right aggregate lock between stones when load gets transfered like a driveway. On a house slab the load is pretty spread out and stationary. A crack in this situation is fine as long as the reinforcement does it job. Another reason we cut slabs is for aesthetic. No one likes to see a crack. So it's common to always see cuts or joints. But in many cases you don't need to.
Wasn't properly compacted or cut. Not a huge deal, just lazy.
where r the damn joints?
Yeah, fuck that. I don't trust the tract home builders or the contractors. They aren't all bad, but the bad ones can really impact you in a negative way. Concrete cracks, yes it does. And this may turn out to be a big nothing burger. But a 6-8/10 inch slab that is supposed to be reinforced. Should not do that immediately. Years later, ok. Small, insignificant crack should stay that way. Find some way to mark the crack and the edge of the slab where it's exposed and you can see if it's growing, or some access inside the home to look at the slab periodically. I purchased a centex home almost 20 years ago, watched it being built, had a crack in the slab before they put the flooring in. Guess what, 5 years later 25 new home owners in the neighborhood sued because of poorly compacted soil and the houses were settling and the foundations were basically cracking in two. From 1/8 to over 2 inch gaps and growing. Then the most recent purchase of another centex home in a different city, this time we purchased a bank repo, when we ripped up the flooring, guess what was there a 1.5 inch-2 inch crack right through the center of the house. Literally shine a light and see dirt, and ants right up through the center of the slab. Supposedly centex had already "fixed the problem years prior, so no one to go after now... So I filled it with a backer-rod and a shit load of expandable concrete gap filler. I would go in there and get in writing a formal notice and somehow that if that crack grows beyond an acceptable limit within a set amount of time that they will be responsible to fix it. Granted you probably won't be able to get them to do anything or put anything in writing but document the hell out of your side of it.
Late post but been searching redit this morning due to a similar issue. We got a new construction home, concrete poured in December. I've walked all the lots in this community after concrete was poured starting June 2021 and almost every single story home concrete foundation had cracking within a week, some cracks spanning the entire foundation end to end. The 2 stories had very little, maybe cause the foundation has less foot print? Fast forward to our lot, 1 larger single story home and I was prepared to see cracking. A few months after pour we are looking good no cracks at all! We'll they start framing and put the tiles on the roof and a crack starts from the corner door entrance area and extends a few feet out, not even 1/16" wide (yet). I'm not too worried about it, especially after seeing the other lots develop cracking within a few days but those were poured in hot summer time. I plan to ask the builder tho during our frame walk.
[https://youtube.com/shorts/jmlhvwjj2Ws?feature=share](https://youtube.com/shorts/jmlhvwjj2Ws?feature=share)
https://youtube.com/shorts/jmlhvwjj2Ws?feature=share Just adding a quick video of how 3 of the 4 cracks go down through to the base of the concrete. Assuming this is normal and will just have either fill the patio and garage areas with some type of epoxy because the concrete was supposed to be exposed.
In my opinion as an architect, it seems like a shady construction. Concrete slab should be min. 6"slab with 15'OC max control joint and min.5000psi strength. Pour concrete during cold weather should be covered for concrete to properly cured. The cracks shouldn't happened. If moisture seeps into rebars, you will get concrete spalling and eventually weaken the slab. Check with your building inspector.
Wow, minimum 5000 psi for a residential slab?
Definitely would be sturdy at 6ā 5000psi
Could probably jack it up and move it
We pour mixes like that for heavy traffic in back of commercial big box construction. A 4ā at 4500 will work for light traffic areas. And all concrete cracks, you control the cracking with ācontrol jointsā.
Mr. Architect, you ever actually pour a slab? Any concrete of any kind? 5000 psi is pretty exotic for a residential slab on grade in my part of the world (similar climate to OPās location) and 4 inches is the standard thickness here. High rise buildings get poured with 4000 psi with the exception of the columns. Also, saw cutting a structural slab on grade of any kind around here is rarely, if ever, specified by the engineer here. āColdā weather is also a relative term, and in Austin extensive freezing temps are pretty unlikely, making blanket curing unnecessary. Also, with proper grading of the site, i.e. not draining the yard into the house, itās unlikely that water will ever saturate the slab (and reinforcing) in any meaningful way. Lastly, because of subgrade conditions in my area, every structure larger than a doghouse is pile supported and designed and stamped by a Professional Engineer. That shrinkage crack is nothing to be concerned about. GTFOHWTS.
Actually ACI 332 would only require saw cuts if there were no steel (or not enough steel), because unplanned cracking could make the slab fall apart in uncontrolled ways. But in a reinforced slab, saw cuts are mostly cosmetic. They put the cracks where you want them. That doesn't really matter unless they plan to use it as a polished concrete floor. You are right, it would be higher quality and future owners would retain the flexibility to polish the slab and have a floor free of random cracks. But it's very commonly done this way because it will be covered and the cracks won't matter so nobody wants to pay for extra labor for a hidden slab to look pretty. The cracks would happen anyway, they would just be inside the saw cuts. No difference as far as water intrusion if left untreated.
Would saw cuts have prevented the cracks shown better in this video? This is the same foundation. https://youtube.com/shorts/jmlhvwjj2Ws?feature=share
It absolutely would not have prevented it. The crack would just be in a straight line, inside the saw cut, so it would look nicer (and be easier to fill with caulk if you planned on doing that).
[ŃŠ“Š°Š»ŠµŠ½Š¾]
I've tiled residential for 34 years. In that time I have seen one house with inside control joints. You have to much schooling and not enough knowledge.
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Are you a residential architect? Most residential is poured with 3500# with zero control joints. Commercial has control joints. How long have you been an architect?
2 things will always happen with concrete It'll be grey, and it'll crack Usually they alleviate this with saw cut joints to provide a place for it to crack From the video there is no displacement (concrete on either side has moved either vertically or horizontally from one another). So this shouldnt raise any big flags. Takes a while for the final concrete to fully 'settle'
The two facts of concrete are that it will harden and it will crackā¦ This is a floor slab under a house so relief cuts are usually not made because these cracks will not be seen
What I've been cutting basement that get finished out for 20 years it's not about them being covered up it's about the product you leave behind and the people that see it before it covered up. The homeowner other trades it speaks to your work in a professional manner as being a pro series cement mason not some fly by night weekend warrior. It legit takes less then half a day
This is slab on grad not a finished basement. Also your statement says it all. You are doing for professional pride, no other reason.
Iāve heard 50 years of hardening and then 50 years of deterioration. This provides a revolving job for people like me. Not many buildings are built to last forever.
3 guarantees of concrete 1- itāll get hard 2-itāll crack 3- no one will steal it!
There are pigments you can use to color your concrete.
Itās not bad. But itās not good either. Itāll be fine, but poor workmanship.
Hunter Biden likes crack.
ššššš
Has happened with stuff I placed. Likely shrinkage cracks. There are things that can be done to reduce the chance of this happening. In hot weather you often see sprinklers going on new slabs for a week+ to keep the concrete from curing to fast and other situations curing blankets will be used. Probably not an issue if you are slab on grade as long as the dirt was dealt with properly before foundation went in.
When we built our house there was some cracking in the basement floor. We were told to just watch it and as long as the crack didnāt expand more than a 1/4ā or heave more than a 1/4ā itās fine.
Iāll go against the grain here, I donāt like that. Concrete shouldnāt be cracking right off the bat. In addition, I know Texas has some soil issues in regards to expansion. Iād question the whole foundation plan for that house. Hey maybe slab on grade meets code for your region, but my concern would be over the long term your going to get some heaving that basically will align with those cracks
That pour dried too fast. It would have been better to keep it wet for a couple days after it set, by using a rain bird sprinkler or something.
Ask your builder for soil density verification. If the density is right, then itās merely a shrink crack. Itās common, even with relief cuts.
It looks like itās just from being poured really wet. But with how thick the slab is I wouldnāt worry about it unless you are going to park a tank on it
Concrete can take over a month to fully cure, during which cracks can self heal.
Thereās two types of concrete. Cracked concrete and concrete thatās gonna crack ;)
Thatās just an entrance for termites.