Concrete Floor question

[Scout3918]

I am in process of having a 30' X 40' pole barn style garage built. They are doing the floor later this week. The contractor said the guys he uses to do floor don't cut or score it. (sorry, I'm not sure if that proper terms). He stated they just pour one big slab. He said his personal garage same way.

I always heard they should be cut to help prevent cracking.

Do I need to insist it be cut/scored or does it matter?

Thanks in advance for any input.

 

[Mancino]

From my understanding, the stress cuts don't prevent cracking as much as they are there to control where the cracks can go. All my buddies in the concrete business, always suggest stress cutting the floor. Because it WILL crack. That's for sure.

 

[Mancino]

Good luck btw! I'm not too far behind you in my build process...I also have a 30x40 pole barn I just framed up. Concrete is coming soon

 

[Scout3918]

Good luck btw! I'm not too far behind you in my build process...I also have a 30x40 pole barn I just framed up. Concrete is coming soon

Congrats on your build too.

Thanks for the info. Yes I hear they all crack eventually.

 

[ForceFed70]

Go with a different contractor.

Seriously - that's some very bad advice. So bad, I wouldn't trust him/her to touch any aspect of the job.

Oh and Manchino is right - the purpose is to control the cracking. WHEN the slab cracks, it'll crack in the control joint. Usually the control joint is full of dirt/debris and you can't even tell the slab has cracked. Much better than some ugly jagged cracks across the slab that you can do little to fix/hide.

 

[Chris705]

Having read many threads on GJ about control joints and this being an early reply to the question, there are many posters who have no control joints and say they have no cracks...I believe there could be floors poured w/o control joints that have not cracked but it is a gamble that I see no reason to take. Your contractor has chosen a sub to pour the floor, that sub says they don't need saw-cuts to relieve stress/shrinkage. Put it to your GC this way. The sub can pour w/o cuts if he guarantees it will not crack within a year. If it does he pays all expenses to remove and replace....if he will not guarantee the floor from cracking then they need to cut control joints....(for a pole barn I like to specify the cuts at every post/pole to prevent cracking there) or add 1/2" foam padding around posts to allow for movement and place cuts at about 10-15' oc. I'd bet the GC requires the mason to cut the slab for you.....

 

[SunsetsAndFriends]

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[Scout3918]

First, go look at "his personal garage" to see how it looks.

*How long has it been since his slab was poured? This will give you some kind of idea of
what you might expect.

*Ask to see a couple other similar floors by this same sub.

Second, wrap all posts with foam expansion joint to help stress relief at those points. The foam expansion joints are perforated about an inch down from the top, so the top 1 inch can be pulled out and Sika-flex or similar can be added later.

Third, seriously consider have the slab saw cut just in case. Because if you get the random cracking running in varying directions across your new concrete floor, you'll not be happy.

I did look at his personal garage it only been poured 2-1/2 years but looks good so far. I checked one more garage they done for a friend and it about 5 years old, it still looks good overall.

I going to talk to contractor and see if they will cut it anyway for peace of mind.

thanks for the advice.

 

[SunsetsAndFriends]

...

 

[Scout3918]

Thanks for the replies and help everyone. They poured the floor yesterday. I went with advice and they are cutting it today.

thanks again.

 

[Scout3918]

http://www.garagejournal.com/forum/showthread.php?t=358501

Link to my garage build thread.

 

[Radix2]

there are things that can be done to minimize shrinkage and shrinkage cracks - fillers and cement content. The key thing would be for him to show you a floor poured exactly like yours to see the result. More cement, higher PSI concrete will shrink more than low strength mixes. Any cuts should be made ASAP if you go that way.

I have 3 areas that where poured in a single day - 2000ft2 garage - sawcut - no cracks outside of cuts, 1350ft2 shop - no cracks outside of cuts, 750ft2 great room - no saw cuts - 15+ random cracks. All the same 6 bag mix .... it makes a huge difference.

 

[SunsetsAndFriends]

...

 

[Scout3918]

there are things that can be done to minimize shrinkage and shrinkage cracks - fillers and cement content. The key thing would be for him to show you a floor poured exactly like yours to see the result. More cement, higher PSI concrete will shrink more than low strength mixes. Any cuts should be made ASAP if you go that way.

I have 3 areas that where poured in a single day - 2000ft2 garage - sawcut - no cracks outside of cuts, 1350ft2 shop - no cracks outside of cuts, 750ft2 great room - no saw cuts - 15+ random cracks. All the same 6 bag mix .... it makes a huge difference.

Thank you

 

[Scout3918]

My floor got cut today.

 

[Radix2]

Let me elaborate a bit on the cracking in the great room. My plan in there is for a industrial/rustic look with stained concrete and a pub sort of theme, so it was a calculated risk to see what we would get as far as cracking. We got more than we expected, but these are still just fine shrinkage cracks, thin and not easy to feel with your fingers. It may be alright when done, maybe not.

I plan on trying the stain and if it doesn't look right I will probably tile the room.

If you really don't like the cuts, filling them with a sealant can take care of some of the dirt issue and make them less visible.

 

[ForceFed70]

My floor got cut today.

Good choice. What lead up to that outcome? Did you ask to have it cut anyway?

 

[Scout3918]

Everyone advice here and couple of my friends.

Why ask for advice and not take it if logical lol. My gut all along said have it cut.

My contractor been good to accommodate my few requests. It was small job for them so no real money expense to them.