I am about to begin on my sub floor constuction. I will be using treated lumber over an existing slab in my attached garage. what precautions and suggestions do you offer?

I live in ohio so moisture and cold temperatures are my main concerns. I planned on using treated 2x4's directly in contact with the cement slab. should a moisture barrier be applied on top of the slab or on top of the 2x4's prior to the TNG osb installation?

and how about insulation? what r value would you suggest?

also with the treated lumber I've read corrosion is a big factor. should I look for special screws and joist hangers? if so any recommendations?

Search the forums for Dricore, Delta-FL and Platon. These are all subfloor materials you lay down prior to the OSB (Dricore has the OSB attached to it). Using these products, you do not need the 2x4's, and there is no wood contact with the concrete. I finished 2500 sf of my basement with System Platon. Total cost for the Platon, OSB, glue, landscape fabric, etc. was $2700.

These products do not require insulation. They allow the concrete to breath so it will remain dry, and prevent that musty order that a lot of basements get when carpet is placed directly on concrete. They also provide an insulating benefit. In Iowa, the basement floor temp is approximately 3 degrees warmer (in winter). Doesn't sound like much, but it is a big difference.

The impact to floor height is also less with these than with 2x4's. I lost 1 1/16 inch, vs 2+ with 2x4s (and the OSB on top).

Tom

i had wanted to stay away from the dri core for shimming reasons and cost. Would I still need insulation if I went with the treated 2x4 and tounge n groove osb?

If you go with Delta-Fl or Platon, you don't need to worry about shimming. You do with Dri core only because the panels are 2' x 2'. You can use 4' x 8' sheets of OSB with the others. I didn't do any shimming with my install. After it's all down and settled for a week or so, just drop a tapcon (or shoot a nail with a Hilti) in spots that may bounce a bit.

As for the insulation, I think you would be asking for trouble. If it gets damp, it will develop mold.

As for costs, I think the Dri core is definitely the most expensive. For my 2500 sf, I paid $1125 for the Platon, and $1300 for the 3/4" OSB.

Tom

ok so I would put the delta fl directly on the slab, then put my 2x4 treated joists on top of that, then the tongue and groove osb?

is that right or am I misreading?

is that right ?

NO:

http://www.bennyswoodworks.com/delta_fl/index.html

so really since I am going to use the treated 2x4's for my subfloor, I have no use for this delta fl... right?


I still need a moisture barrier for the tongue and groove osb wouldn't I?