Ripping out concrete floor, pouring new

[Chris Fite]

For what it's worth, the slab in my shop is independent of the footers because it has radiant hydronic heating tubing installed in it. The slab is separated from the footers by rigid foam board insulation except for the top edge where the foam board tapers at 45 degress to the footer. The slab is on top of foam board, too. This method keeps it insulated from the outside. There is nothing next to the shop to which rebar could have been connected.

Control joints were cut in the 24' x 28' slab and slurried over for appearance. There are some ever so fine cracks along the control joints, visible through the epoxy coating on the floor. Lo these 7 years.

If it moves, it moves independently of the footers.

Chris

[Todd Brewer]

The only reason to have the slab rebared to the walls is if your base is not solid. Is the base compacted?

Compacted only to the extent of undisturbed soil.

For what it's worth, the slab in my shop is independent of the footers because it has radiant hydronic heating tubing installed in it. The slab is separated from the footers by rigid foam board insulation except for the top edge where the foam board tapers at 45 degress to the footer. The slab is on top of foam board, too. This method keeps it insulated from the outside. There is nothing next to the shop to which rebar could have been connected.

Control joints were cut in the 24' x 28' slab and slurried over for appearance. There are some ever so fine cracks along the control joints, visible through the epoxy coating on the floor. Lo these 7 years.

If it moves, it moves independently of the footers.

Chris

I tried the control joints filled with slurry the first time around, that and being terribly uneven is why I am replacing it. Some cracks appear to have followed the slurry filled control lines but others are totally random, Some opened up more than desirable with chipping along the edges of the cracks. Glad to hear your slurry fill control joints worked out for you. My concrete was in many ways a disaster.

They're tearing out the concrete today and tomorrow. So I need to decide soon.

[tyler mckee]

I do dirt work for a lot of new homes and the only we are requiref to tie the foundation wall to the slab is if its a 10'+ tall concrete wall. Depends on the original engineering. Just helps hold the wall up when it has 10' of compacted fill trying to push it out. How tall is the concrete wall, how much is buried, inside and out?

[Jim Andrew]

Haven't seen any pictures of the building, but if you compacted the base down to the dirt, should be solid. Floors fail when the base is not compacted. All concrete cracks, prefer fibermesh myself to wire, it is like hair mixed in only fiberglas, and will keep the concrete together even if it does crack. Only place I like expansion is on the edge of door openings, the main floor will only shrink, but can put pressure on the edges of door openings, and cause a big crack.

[Ole Anderson]

I don't understand why you would fill the control joints with an incompressible slurry. Typically you will fill the joints with an urethane or polysulfide concrete joint material that will have some give. Yes, the epoxy coating may show cracks, as it will with the slurry, but the flexible joint material should continue to seal the joint from water intrusion and slab ants. And I would recommend having them use a 1/4" saw blade rather than a 1/8" blade as the wider joint will allow twice the movement before the bond between the filler and the concrete gives way.

[Todd Brewer]

Decided to not use expansion material around the perimeter and not going to tie rebar to slab to footings.

This is an on-grade garage, stem walls are 6" and 12" high so not holding back anything.

I was told by the previous contractor that filling the joint with slurry would only result in a hair line crack. That was true for another poster in this thread but did not work out for me. I will fill the control joints with something semi-flexible as Ole suggests before I epoxy coat. Although my reason for epoxy coating has been primarily remedied by new concrete. The epoxy coating was to hide repairs to the original floor, but it turned out to be too risky to try and repair. I have the epoxy and still may use it, but the new shop floor looks good and I now worry about scratching and damaging the epoxy, even though it is a very high quality epoxy.

Contractor will pour garage side on Friday!

[Richard Jones]

Sonolastic NP-1 is a great urethane joint filler.............

[Todd Brewer]

I've used a product called NP-1 and it is indeed an incredible product! Highly recommend it.

It's been several months since the new concrete was installed. They did a great job. They compacted the soil before pouring but did not tie the slab to the foundation. I don't see why it would move. Very happy with the new concrete (so far).