Hi there,

I recently saw a posting where someone said that they use a thin concrete slab rather the gypcrete... I have been planning to use gypcrete but would really like to know what other materials there might be such as concrete, what formulation works well etc... etc... any experience out there good or bad??
Thanks

George

There are SCC concrete mixes available for your purpose.
Inquire at your local Ready Mix Co and speak to their tech.
There is some proprietary product coming from EU that is available.
Darotop is one.

We  have a 2" concrete slab on a plywood deck.  We acid stained for a finish.   We are more than happy with the result.

We beefed up the floor joists at they are on one foot centers. We also placed a plastic vapour barrier between the plywood and concrete.

 

Thanks Eric! sounds encouraging, I'll inquire locally... and also research the Darotop product that you mentioned.

Jmagill, I had my flooring system designed to handle the weight so I'm already on 12" centers, and I've allowed 1.5" for the thin slab... I just don't want to spend the $2. per square foot for the gypcrete... at 4300 square feet it adds up... How long have you had your slab and how is it standing up to heating and cooling cycles... any cracking? I'm also wondering if you were able to get it level enough using standard flatwork procedures or ? any special formulation on the concrete mix? and what was the purpose of the vapour barrier? I was under the impression that you wanted your thin slab to adhere to the plywood deck rather than to have it just float on top... otherwise it might be too noisy? am I wrong on that?

In general... what's the best internet source for Pex, connectors, manifolds etc... I'll be needing it for my floors as well as plumbing

Thanks!
George

At the time I did the research, the vapour barrier was so it woul not adhear to the deck. That reduces cracking when the building shifts. We do have some cracks. We did no scoring and the cracking is where two rooms meet. Next time I will be putting in either scoring that looks like tile or wood thresholds in between rooms. I hav egrouted the cracks with concrete filler and stained it to match the floor. It just adds to the character and it most places is where we have throw rugs.

The floor has been in place 7 years. No noise, I don't know what would cause that. The floor is level ( we had it poured and finished) The edges are covered with trim at the walls.

Thanks for the information and the tips! I think that I was heading down the wrong path with regard to the having the slab stick to the subfloor... what you say makes a lot of sense... in addition the vapour barrier will serve to keep moisture from infiltrating our heating envelope... since I'm sealing off the attic space (no vents) and having foam insulation sprayed right up against the inside of the roof deck this will be particularly useful!
Thanks!
George

How did that insulating the attic work out?  Any issues with no venting?