Install help over unique radiant subfloor

[willkere]

Hello everyone. I hoping for help with my install questions for a unique situation because of the radiant heat system that I installed.

Background: I'm installing 600 sq ft in the lower level of my house (below grade daylight basement). I installed a hot water tube radiant system over the concrete slab.
Product: Strand woven bamboo 3.5" x 6' x 3/8" - Manufacturer says it can be floated, glued or stapled
Subfloor: This is where it gets tricky...I installed dricore over the concrete slab (secured to the slab), a layer of radiant reflective material, and then strips of ~3/4" OSB to create small tracks for the tubing to run in between. The OSB was screwed down to the dricore and then we ran tubing with aluminum panels to help spread out the heat. The flooring will run perpendicular to the majority of the tubing. I'll try to post a picture of my actual project but it looks a lot like this except with tubing that is 12" apart: http://www.radiantcompany.com/details/suspendedonslab.shtml
Questions:
1. I've read that I should use cleats because the strand bamboo is so hard the staples won't go through. But at only 3/8" thick, a cleat seems like it would split the tongue. Which would be better?
2. An installer came over to give me a quote and he suggested gluing in between the tubing tracks and nailing with staples. I've never heard of doing both so I didn't know if that would be a good idea.
3. I have a few high and low spots. I'm going to sand down the high spots but I'm not sure what to do with the low spots. I can't pour any kind of self leveler but I've heard that I could potentially use craft paper to build up spots? Any other thoughts of what to do?

Any help would be really appreciated.

 

[rugaddict]

in my opinion any flooring other than ceramic tile over radiant heat is just asking for trouble ---i dont know what the moisture content of your bamboo is but your plan is basically to install it on a griddle---it might dry it out a tad

 

[willkere]

I already have 1600 sq ft of the flooring in my garage so its going in one way or another. 600 sq ft is downstairs with the subfloor I described in my original post and the rest is going upstairs where a different method of radiant was used.

The manufacturer says that the flooring can go over radiant heating which is why we purchased these. Any thoughts on my 3 questions?

 

[Ken]

Well, if its going in one way or another then I guess you dont need our help, lmao!

 

[Ken]

As far as your questions are concerned. Definitely use cleats. I have four different guns for all the different species of wood that I install so make sure you or the "installer" is using the correct one. If your "installer" suggests a certain method of installation I would hear him out afterall, he is the professional and you must have called him for a reason. Leveling can be done over wood substrates with multiple (up to six) layers of 15# tar paper or using different thicknesses of wood.

 

[Ernesto]

Do you own a professional grade moisture meter?

 

[willkere]

Ken - thank you for the help with the cleats and tar paper. I've installed the radiant system myself so I'd like to finish the project off by installing the floors myself. I purchased nail gun that will shoot 16ga cleats but its made for 1/2" flooring. I'm planning to increase the thickness of the bottom plate to line up with the 3/8" floor because I couldn't find a correct adapter. I'm going to try it later tonight and see if it doesn't split the tongue. Sure seems like a 16ga cleat will be too thick.

Ernesto - I do not. I have what would no doubtedly be considered an amatuer meter. I'll look into renting a professional one if you think it'll make a big difference. The meter that I have says its accurate to +-2% below 30% and +-4% above 30.

I live in Seattle if that matters from a moisture/radiant floor perspective. I've installed a mixing valve on the hot water tubing so that I can turn the water down in this lower area where the tubing is effectively touching the flooring whereas the upstairs the tubing has to go through the subfloor.

 

[Ernesto]

This is sounding scarier by the moment. The installer said what? Maybe it is best you do it yourself. Did I just say that? lol No I didn't mean that, find a different installer!

I'd say there is insufficient info on this product to make any comments, cept pin meters dont work on stranded.

 

[FloorMaven]

Questions:
1. I've read that I should use cleats because the strand bamboo is so hard the staples won't go through. But at only 3/8" thick, a cleat seems like it would split the tongue. Which would be better?
2. An installer came over to give me a quote and he suggested gluing in between the tubing tracks and nailing with staples. I've never heard of doing both so I didn't know if that would be a good idea.

I have concerns about any type of mechanical fastening...one puncture is a headache-and-a-half. I think I might consider gluing between tongue and groove and gun grade construction adhesive between flooring and sub-flooring.

First I think I might test by gluing a few boards together and laying them out; cranking the heat to see how they react.

 

[willkere]

For what its worth the moisture meter reads 10-11% on the subfloor with the heating system off.

I was planning on snapping chalk lines on the tar paper as I laid it so I know where the tubing is so I feel comfortable putting cleats in between the rows of tubing. The turns will be a bit tricky but I have a template of each curve which I thought I'd use while nailing.

Any thoughts floating the floor? I've cut out the drywall along my walls at the height of the flooring would and will be putting 1.25" width trim so the floor would have 1.75" of expansion on most all sides (there are cabinets so that area will only have the trim width of expansion).

Right now I'm thinking of a hybrid approach with glue in the T&G, some cleats in between the main tube areas, and then as FloorMaven suggested some good construction adhesive (is that what you meant by gun grade?).

 

[Ken]

While my installation experience pales in comparision to some of the vets on here, I have done a ton of bamboo. It can be a tricky product to work with if youre not careful and I dont think its something to experiment with especially after youve sunk a bunch of money into it. In my opinion those 16 gauge cleats are too big and will split tongues. You need 18g, look into the red powernail gun, thats my go to for stranded. Even if youre moisture meter isnt top of the line at that 10-11% its probably at an acceptable range however I would definitely leave that flooring open for a couple weeks to let it soak in some of the moisture in the house. It comes out of the mill at around 6-7% (if you could measure it acurately, usually with stranded you cant). I would not float the bamboo, Ive heard horror stories. I would however run that floor right under the cabinets especially if going around them would compromise your expansion. Do not mess with expansion on bamboo, it will come back to kick your ass.

 

[willkere]

I just read the bamboo with my meter and it showed 11% on two pieces from different boxes. The boxes have been in my garage for almost 2 months. I brought them in last night and took off all of the plastic. I'll look into the power nailer you mentioned.

I think I'm going to try gluing a few boards together and crank the heat to see what happens.

 

[Ken]

That 11% isnt accurate. you need a conversion chart which can be obtained from the meter maker. Shhh, Ive already said too much.