Doing a 400 sq ft bamboo install in a garage conversion. The slab from the house extended into the garage four feet, then it stepped down 2 1/2", then slopped out. We leveled the sloped section with 3/4 CDX over treated 2x rippers, and radiant was strapped to the rippers. The existing bit of slab was then leveled out with floor leveler and it now transitions sweet with the CDX.

I have placed miles of Oak and refinished more than I can recall, but I have NEVER placed pre-finished material, or bamboo. I plan on stapling with Bostich M-111 (2"), and placing jumbo tec between bamboo and CDX. The walls get plaster, so I plan on doing that first and letting them dry out a bit before installing the floor; therefore I have to mount the baseboard prior to installing the floor.

Questions;

1) should I do the nail down first, then the glue down; or do the glue down first, then the nail down?

2) The CDX is super flat (used strings on the rippers), how often do you staple?

3) Is the tongue on Bamboo more brittle?

4) Solid vs. Engineered? 3 3/4 wide vs 4 7/8? (both of these as they relate to Radiant heat!?)

5) When face nailing the last boards, or if dings occur, is there a way to patch pre finished material?


Any tips on things to watch out for with bamboo would be great, Thanks!

The manufacturer's instructions should answer all these questions.

lol
Thanks!

I hope you put a moisture barrier under the wood subfloor part of the renovation!!!

did not!
The subfloor sloped from about 2"-4". I readheaded/liquid nailed down 2x4 trtd flat 16 oc, so any moisture barrier would have had over 100 holes in it. What is the theory here, that the heated space will draw moisture up thru the slab? We average 10-14% relative humidity here in NM.....not a ton of water floating around.

The holes would not be out in space. They would be sandwiched between plywood and 2x4. It actually works in a manner opposite of what you describe. It is when you crank the AC that moisture will migrate to the top of the slab.(if it is there in the first place.

"if it is there in the first place"
Are saying the moisture barrier is keeping moisture from migrating from the interior and collecting on the top of the slab and rotting the 2x4's;
or are you saying that by cooling the interior, moisture from a) a wet slab, b) wet 2x4s c) wet plywood, will collect on the slab and rot the 2x4's? What if all three are dry, where will the moisture come from, under the slab?

If it's coming from the interior, what keeps it from getting trapped by the 15lb felt under the flooring and rotting the flooring from the underside?

thanks for replies

What we are saying is, all concrete has moisture vapor emissions. Bamboo and solid wood, don't like moisture vapors, even with plywood there, which will hold the moisture for the bamboo to cup, and even buckle.

It is mandatory to place a moisture barrier over concrete, whendoing a project like you have.


Asphalt mastic!!!!! The sleepers should be laid into asphalt mastic and then coated with asphalt mastic. Pressure treated wood, has a very high moisture content that will transfer to the plywood, and you can get strips of cupping where they are under the plywood, unless a moisture barrier is placed over them.

I beg to differ on treated being any different than any wood. Once wood is acclimated to its' environment it is as dry or wet as the air around it. You can kiln dry wood, but that is meaningless once you reintroduce it to a humid environment.

You are going to put asphalt mastic in an interior environment!!??
I could see plastic between the CDX and the sleepers.....

So then by cooling the interior space, water is pulled up thru the slab...if it's there.....sorry to redundant, but it seems a critical point and I don't see consensus, yet

come to think of it, if you put the plastic between the CDX and the sleepers you'll punture it every 12 inches with your staples!

You put mastic under your sleepers, you can't liquid nail 'em, which is vital insurance against sqeaks because you know things are gonna react down there to that radiant. As well the screws holding down the CDX are penetrating, no?

ok, I'll keep yappin.....
how about a glue down? There is no barrier there except for the glue; does this act as a barrier? Wouldn't the water basically kick the glues a** after ten years or so?

curiouser and curiouser I become

You can beg all day long, dude, but pressure treated lumber tends to be around 20 percent irrespective of your wishes. This is because the preservatives used in that process are remarkably hydrophilic. Pressure treated stuff will be a killer when it is put in direct contact with the flooring assembly.
I personally see no major problem in using PT 2x4s for sleepers, but it certainly isn't necessary. If it were, you would need to rip out all of your interior walls and build them all over again using pressure treated stuff for all the sole plates. Are you following me?

With respect to your assertion that staples will puncture the polyethelene draped over sleepers, That could only happen if you were using a staple much longer than you need.

In the end, it is your floor. If it fails, it costs me nothing. I can only tell you what I would do in your situation.

Good luck,
CHU

not trying to be argumentative, just trying to learn. I wouldn't have posted this thread if I didn't respect your opinions!
I have always been required by inspectors to use treated on the bottom plate on all walls, interior/exterior, post ends, stem walls, bond beam tops and sometimes deck joists. Hell in Hawaii we framed the whole house with treated. You know how much a sheet of treated 3/4 T&G weighs!?!

So at this point it looks like I should pull up the CDX, lay down a layer of 4 mil plastic and then carefully re-sheet. Can you give me your thoughts on why no moisture barrier for the glue down to slab?

Don't you love DIY'ers!

They jump us for saving them a ton of money, because it isn't what they want to hear.

They would rather argue with an installer that has been there done that and a failure inspector/installer that gets paid good money to go look at what your fixing to do, just to tell you where you went wrong. We'll call this a free consultation.

Bostik's MVP, Is a moisture blocker/barrier that is applied and let cure, before Bostik's adhesive is applied.

Other glue manufacturers, have similar systems for moisture vapors from concrete. All concrete should be tested for just how much vapor is present.


Oh, ya, your gluing a section. and trying to fasten the remainder. I see failure written all over this