Saw cut locations

[Evilcactuar]

I've got my floor being poured tomorrow, it's a 30 x 60 pole barn. My issue is that I've put 5 doors on one side, so the posts don't line up front to back. I haven't decided what I'm going to put on it as a finish, so I'm not sure how obvious the cut locations will be, but I'd rather have funky looking cuts than uncontrolled cracks. The concrete guy said he would probably do some strait cuts, and he'd probably regret it, so it was up to me. I drew up my idea, I wanted to bounce it off you guys and see if anyone had any input. I was trying to keep options of putting a 4 post lift in any (or all) of the bays, the one I was looking at is 8.5ft wide base to base.

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[joes169]

Not sure what the floor thickness is, but assuming 12' x 10' joint spacing (I can't actually read the dimensions on the image, but you said it was 30' x 60'), I'd say you're pushing the limits on a 5" thick floor.

On pole buildings, we ALWAYS wrap 1/2" foam expansion around every post to allow for slab shrinkage w/o binding and we ALWAYS saw control joints to the center of every post.

Your 4 angle cuts on the right side are similar to what I typically do, except that I would bring them farther into the building to get the angles less than 45 degrees to the main control joint. As you have it sketched, you're begging to get a crack jump outside of the control joints.

 

[Evilcactuar]

It is a 5 inch slab. I appreciate the feedback, I can angle those out further. Would you suggest I do something similar at the front? The posts around the door are only spaced 2.5 ft. Is this what you're talking about? I have permacolumns, so the bottom is concrete. Any suggestions on how to affix it?

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[joes169]

It is a 5 inch slab. I appreciate the feedback, I can angle those out further. Would you suggest I do something similar at the front? The posts around the door are only spaced 2.5 ft. Is this what you're talking about? I have permacolumns, so the bottom is concrete. Any suggestions on how to affix it?

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We're setting up a basement floor tomorrow at a new house where we already poured the garage floor, I'll try to remember to take a few pictures of the angle joints to the door openings.

We usually use 4'x 8' sheets of 1/2" "R-board" to wrap the columns, which is just foil faced insulation we rip to the desired height on a table saw. WR Meadows makes "Deck-O-Foam"which is cheap and works well also:

https://www.whitecap.com/w-r-meadow...zl05-rbqSV4YXWgedcaAj0cEALw_wcB#-525DOF126X6/

This is excellent stuff to attach either kind of expansion joint with:

https://www.ebarnett.com/Sku/441396...StdbBVIFzMnk9GmslWoaAqwSEALw_wcB&gclsrc=aw.ds

 

[Evilcactuar]

Really appreciate it, thank you

 

[ddawg16]

Concrete expands and contracts the same in all directions.

So....you want the X and Y to be the same.

 

[ConCretin]

Control joints are intended to induce cracks from shrinkage where you can't see them rather than random cracks that you can. You want to cut them as soon as possible after finishing ideally with an early entry or soffcut saw. The cuts should be 1/4 of the slab depth.

Recommendations for CJ spacing start at 8-12' but with some attention to overall crack control, you can spread them out to 15' or more. Keep the panels created by the CJs as square as possible with a maximum ratio of length to width of 1.5 to 1.

It looks like you have them 10' on center. If you keep the slump under control, cut the joints in a timely manner and cure the slab properly, you could safely go with one longitudinally and three across resulting in 15 x 15 panels.

Give my Guide to Floor Slabs in the link below for some additional thoughts. Good luck with the pour.

Edit; just noticed posts and the funky diagonal cuts. I wouldn't bother with them just to line the cuts up with the columns. The cracks probably won't follow those cuts anyway. Just wrap the columns with expansion foam to soften the re-entrant corners and provide a little give.

 

[Leaflessshadetree]

The 2 60' cuts look fine.
I'd cut the others between the doors and not worry about being aligned with the poles.
Should make squares about 10'x12' which is fine.

 

[Evilcactuar]

That's essentially where we landed when I talked about it with the contactor this morning. We ran into a host of other issues, so I didn't think to come back and reply until now, but they're running the trowel now, we did wrap the posts with some foam, and we're cutting shortly post to post long ways, and strait back between the doors. We added some 1/2" rebar in the door openings as well as between the post and where the cut will be. One of the issues that cropped up ended with a thicker slab in the back than in the front, so it's closer to 7 inches on the back wall. Either way, it's done now, so fingers crossed. Appreciate all the feedback from everyone!