Shed

[Joe Bass]

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I'm too old for this ****, so I hired a crew last week to do a patio for me. 22' x 16'.
Pressure cuts were made at 8' and two at 7' for the 22' length. One cut on the 16' width - in the middle at 8'.
An 8'x8'x5" slab with mesh for a shed won't need a cut. One down the middle, if it puts a smile on your face, but not cut in 4, as suggested.[/QUOTE]


Was just a guess, didn't mean to give out wrong info.
But I agree that a cut may not be necessary for that size slab, as I did not cut mine.
Thanks for the ccorrection.

 

[Gary]

Yes, there's no laws or codes for this type of thing.
Usually a well layed out 10'x10' should get away without a cut.
With mesh properly placed, even if the pad cracks, it's not going anywhere.
I'd rather deal with that, than a cut or two in the floor - nuisance control.

 

[crankcall]

If there's an engineering formula for control lines I'm not aware of it. Common sense should suffice.

.

There is a formula for control lines and also for expansion joints. They need to be placed in specific spots to achieve "control" and allow expansion or contraction to take place. This is because common sense isn't that common on most building sites.
But it really doesn't apply to a backyard shed pad. Not needed.
90% of cracking occurs because of poor prep work UNDER the pad, poor excavation, not removing the sod to firm undisturbed soil, not putting at least 3-4" of crush stone down to allow the slab to properly bed. Proper process and its there forever.

I looked at engineering drawings last week for the Hamilton Harbor new docks, they will be floating concrete. That's some interesting stuff.

 

[RockerGuy]

There is a formula for control lines and also for expansion joints. They need to be placed in specific spots to achieve "control" and allow expansion or contraction to take place. This is because common sense isn't that common on most building sites.
But it really doesn't apply to a backyard shed pad. Not needed.
90% of cracking occurs because of poor prep work UNDER the pad, poor excavation, not removing the sod to firm undisturbed soil, not putting at least 3-4" of crush stone down to allow the slab to properly bed. Proper process and its there forever.

I looked at engineering drawings last week for the Hamilton Harbor new docks, they will be floating concrete. That's some interesting stuff.

Yeh, I recall there was a formula for it but too lazy to look it up. Even highway "on ramps" have expansion slots and bridges have some "floating" support on them to allow them to expand. Some go as far as putting rollers on them so when they expand & contract they move over those rollers.

When I was helping build foundations once upon a lifetime, we would have to compress the mud before we even pour the concrete. Can't have one section sinking faster than the other.

I've seen the floating concrete in the Caribbean, they use them as yacht docks. Pretty impressive. I didn't get a really good look at how things work but it was cool walking on floating concrete

/nerd mode

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