On wide plank installations, in addition to scrupulous acclimation on site, we usually do full spread adhesive in addition to nailing/stapling. We have mostly concrete slabs and few basements. We use a moisture barrier under the plywood subfloor and glue directly to the plywood, which would differ from what you have. Customers use HVAC mostly year round so floors undergo relatively small fluctuations in indoor humidity.

My favorite glue for this is Stauf WFR930. It has decent flexibility, like the old chlorinated solvent adhesives. It's an alcohol base so it smells a bit but that's only an issue during construction.

You should follow the manufacturer's guidelines for installation. Their guidelines supersedes any other recommendations.

Here is what we like to do regarding Glue Assist and Nail Assist installation.

Glue Assist:

Roll on vapor retarder

For 4" , apply bead down the middle of the floor board and nail/staple 6-8"

5" & 6", Apply beads directly onto subfloor every 6-8" spacing and trowel with the short side of the trowel and nail/staple 6-8".

Nail Assist:

7" and up, roll on vapor retarder and full spread adhesive and nail/staple every 12 - 18".

Again, follow the mfg's guidelines. They may advise against these recommendations.

Thanks for the responses. The wood came from a mill in TN. I called and talked to the the company I ordered through and they sent me the NWFA installation guidelines, but didn't have any specific beyond that. The NWFA installation guidelines don't seem to get too specific on wide plank installs though. So it looks like I don't really have any mfg guidelines to be following here.

G&S, you said use a roll on vapor retarder and then apply beads of glue directly onto the subfloor? How does that work? Are you putting the vapor retarder and then applying beads of glue on top of that, rather than the plywood subfloor?

Or did I misread that and you meant skip the vapor retarder and apply beads directly to plywood subfloor and then nail?

What vapor retarder do you use, and what glue for your beads?

Thanks again for the thoughts.

Jason

And just for fun, the HVAC system has been upgraded to include humidity control. The indoor humidity control (dehumidifier/humidifier) is the SINGLE MOST IMPORTANT item you will need to ensure wide plank wood from cupping.

Hiring an NWFA Certified Installer/Refinisher is going to go a long way to ensure this install is done properly for your situation.

www.nwfa.org to find a professional near you.

Those “ certified installers” are hard to come by. The closest one to me is 50 miles away and does not work in this area. The next closest are all about 100 miles away. Hopefully there are competent flooring professionals closer than that for other people.

You can use Loba pu-280 or bona r541 vapor retarders. Apply 1 to 2 coats , allow it to dry. Then apply adhesive on top Assisted by nails.

As as far as adhesives. It will depend on what is available in your area. Look for Wakol, bona, bostik, stauf , mapei and Pallman.

Interesting, so do the liquid vapor retarders serve the same purpose as a physical vapor barrier, but also give you the benefit of being able to glue directly to them?

I assume bona r540 is the same thing as bona r541, I couldn't find anything labeled bona r541, just r540?

The liquid vapor retarder will perform better than the paper material. Apply one coat it is a vapor retarder. Apply two coats it is a vapor barrier. It also, promotes adhesion for adhesives. It will cost a lot more than the paper material.

Yes, R540. It is fairly new on the market, but does the same thing as the PU-280 by Wakol.

Please match the adhesive to the vapor retarder. That is to say, if you are using Wakol adhesive then use the Wakol retardant. If you are using Bona adhesive, use the Bona retardant.

It is the simplest way to keep everything happy-happy. A wide plank floor (anything over 4" is considered wide) needs special love and attention from the installer and the homeowner when working in a humid environment.

Do you have the upgraded HVAC humidity control?

Without that humidity control, all else is in vain.

Good to know, I'm looking @ going with the Bona products. I have a company coming out to quote me on installing a whole house steam humidifier system for the winter months. It will use the existing duct work. I don't think I will need a de-humidifier in the summer, as the HVAC system keeps the humidity under control pretty good.