Glue or Float premium wide plank engineered hardwood floors?

3 years ago

Looking to install Monarch Wide Plank Forte Bianco - 8" wide, 3/4" thick, 2'-8' length planks over original douglas fir subfloor throughout 1906 Berkeley home. The question is, to glue down or float? I'm leaning towards floating as I like the idea of less glue but I really have no idea which is better. Looking for some insight. If you use a thick cork underlayment do you really feel a lot of flex when walking?

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SJ McCarthy

3 years ago

So long as the subfloor is reasonably flat the cork will do all the flexing you need. As a cork expert, I've used 6mm cork underlay to "eat" 1-2mm worth of variation. Because cork is solid but not rigid, it will do a little bit of correction for you.

Besides, if you glue down the floor you have to glue down the cork and that takes +++glue. We call it a double stick. It can add up to $2/sf just for the glue. And you can't lay the hardwood if the cork is still damp from the glue.

If you float the flooring you float the cork. Simply lay the cork sheets PERPENDICULAR to the direction the floor will run. Like most things in the building world, it always makes sense to 'off-set' your layers. If you would do it with plywood sheeting you might as well continue with the cork. It takes 30 seconds to determine the direction of the hardwood. You simply run the cork in the other direction.

The issue won't be the cork or the glue. It will be the width of the planks. Those wide planks will move more than you ever thought possible. Regardless of the structure of he plank, the wide planks will be MUCH more unstable than a narrow plank.

That's why the home's HVAC system should be investigated and upgraded - if needed. You MUST keep the indoor humidity stable between 45%-55%. If your current system does NOT have that capability I suggest you take that $2/sf savings on the glue and use it to invest in a whole home upgrade.

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Comments (7)

duchessOFdiy
3 years ago
last modified: 3 years ago
If you can float it, definitely float it. Especially if you are doing it yourself. HOWEVER, it is usually recommended that wide planks be glued down. I installed 9” wide white oak hand scraped & wire brushed engineered HW flooring throughout my home about 6 years ago. I had to glue down due to the width if the planks. My home is on a concrete slab. I used a glue that did not require an underlayment. It was more expensive but I didn’t have to buy & install underlayment so it off set the cost. NAIL DOWN was the way most recommended to me for wide planks but I obviously did not have that option on the first floor in my home due to the concrete slab. Is nail down an option for the flooring you chose? Are you having someone install it for you? What I did and what I recommend anyone do is call the manufacturer of the floors you purchased or want to purchase for your project and ask them what they recommend for your subfloor and what specific type of glue or underlayment works best for your situation. Then you will know for certain what is best for you:) that worked well for me as I have not had any problems with my floors and they look great. GOOD LUCK :)
Jackie Patterson Brenner thanked duchessOFdiy
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Jackie Patterson Brenner
Original Author
3 years ago
Thanks for your comments! We will be having the floors professionally installed and we live in Northern California so humidity isn't really an issue. We so have the option to nail down as well. I like the idea of calling the manufacturer! I'll give that a try.
User
3 years ago
last modified: 3 years ago
Humidity is very much an issue. There is too much of it in summer and not enough in winter. Without very good control of that, and no wide swings, you are setting yourself up for an expensive failure. That means no open windows. Always use the HVAC. No 90 % summer morning readings. That means that an oversized unit that has difficulty dehumidifying at low temperature deltas in the AM will need to be replaced with one properly sized, and that has a multi stage. Plus a humidifier add on for the winter. You can’t have below 30 or above 60. That is really hard to achieve.
SJ McCarthy
3 years ago
Wide planks in your size range MUST be glued...using full-spread adhesive. Nail only = ABSOLUTE no go!
Jackie Patterson Brenner
Original Author
3 years ago
@SJ McCarthy what about floating with cork underlayment?
SJ McCarthy
3 years ago
Floating will work but you will need 3/4" expansion gaps at all walls AND you MUST have T moulding in all doorways.

Glue or Float premium wide plank engineered hardwood floors?

SJ McCarthy

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