While I have installed solid flooring by nail-down method in the past, this is my first attempt at doing a glue-down of engineered flooring over concrete in a radiant floor house (above grade). The problem, if it is one, is that the unfinished engineered flooring has a slight bow in each board. By this, I mean that the 3" wide boards (5/8" thick with a 3/16" wear layer and the remainder being a 5 ply hardwood plywood) are bowed upward about 1/2" in the middle when laid flat on the floor for a 7 foot board. Even the small 1 to 2 foot boards have a slight upward bow to them. Is this acceptable for a glue down? Will I need to weigh down all the flooring once laid (and before the glue has set up) to get the adhesive to bond? Is that typical for a glue-down job, or should I return the flooring? Thanks for any advice.

Mods: Please don't delete this time. I really need some advice. You used to sell this product. Maybe this is why you don't anymore? I would mention the brand, but if I do, you will likely delete my post again, as per your rules regarding mentioning anything that you don't currently sell.

Thanks.

We install, sand and finish a lot of this flooring and have had the same problem in the last year or so. I talked to my distributor about the problem and was told no one else has ever complained about this. We looked at all the stock in his warehouse and every pallet was bowed.
This flooring takes twice as long to install when it is bowed, I say send it back.

Bowed is sideways. Banana boards are up & down.

I find it becomes a concern around the perimeter, and not so much out in the field of the installation. Weight it down.

It means there is an imbalance of MC from top & bottom of an engineered board.

Thanks for the replies so far. I would prefer to not have to ship it back (would cost a lot). If I weigh the first few rows down with bricks or concrete blocks (or is there something better?) and let them set up, would the subsequent rows lay down OK simply by the fact that they would have their tongues going into the grooves of previously laid flooring, or would I need to keep weighing down all the rows? If the latter, then I may just look for another product.

I guess "bowed" was the wrong choice of word, they are "bananas" (the boards are perfect in every way except they will not lay flat). I spoke with the manufacturer and they said I should acclimate the boards. I am awaiting a moisture meter. I agree, there must be a difference in moisture content between the hickory wear layer and the plywood it is laminated to. Not sure how to correct this in the field. Thanks again, appreciate all comments.

Turn the boards over so they bow up in the middle, instead of on the ends, and put a little wieght on them to keep the flat against the concrete.

Kind of sounds like your concrete may be high on the moisture vapor emissions.

My concrete is flat and dry (over 8 years old). I did a test to see what it would take to flatten out a 33.5" board which is bowed about .220" in the middle and it took 23 lbs of pressure. Obviously, the longer boards, though bowed even more, take less weight to flatten. I finally received a reply from the manufacturer, and here's part of what was said: "...regarding bowing in 3" Hickory Character grade. Our manufacturing process does allow for up to a 1/2" upward deflection in the center of flooring when ends are in contact with floor, providing the bow is "soft" and can be flattened with light to medium pressure."

I have requested that they define "light to medium pressure". I am sorry for wasting all of your time on this forum, but I have a nice, quality house and don't want to cheapen it if this flooring doesn't install well. I really do love the look of the wood and milling quality, but the bowing has got me puzzled. What would you pros do in my situation? I had this stuff shipped from the Midwest to Idaho (local distributor wanted way more) and to return it would set me back both financially and time-wise.

How did you actually determine it as acceptable levels of moisture vapor emissions? Remember, vapors can't be seen.

My concrete is not a concern. It is dry, trust me. I wish someone would address my concerns regarding the viability of gluing this stuff down and making it stay down instead.

As an alternative, this company has a product that is 1/8" closed cell pad with one sticky side that is supposed to allow installing this as a floating floor. Would this work better than doing a glue-down if the boards are bowed?

Gary, any experience with this engineered flooring (I really trust your opinion)?

Rudy, The only problem you will have is holding each board down and getting it to pull into place properly. That is assuming you have followed all the manufacturers recommendations (flooring and adhesive) and have properly checked for any moisture problems in the slab.
As I said, we have installed this flooring many times with the problem you mentioned and the only problem we have had is slow installation, once it is in place it stays down if you have done everything correctly.

Buddy, I really appreciate your reply. What have you used to hold the boards in place? I was thinking of using 1/2 thickness concrete blocks which I have about 30 and whatever else is handy that won't ding the wood too much. Thanks again.

Use the cardboard from the cartons of wood, to place your bricks on.


I only trust a calcium chloride test, a Tramex Concrete Moisture Encounter, or and in-slab humidity test. If I trusted everyone that said their concrete was dry, while I was looking at a cupped floor, I'd be a piss poor failure analyst.

I just got my BR111 Triangulo Engineered Brazilian Cherry in today and I've got the same problem Rudy had. I've opened 2 boxes and nearly every board is bowed towards the top. Is this normal? Will it change once it has acclimated? I was planning to float this next weekend - Is this going to be a problem?

The factory replaced my entire 500+ SF of flooring but unfortunately the new stuff is also bowed, but not as badly. They never admitted fault nor would they answer whether it could be floated. I seriously doubt it could be floated since their floating system consists of a foam mat that is sticky on only the hardwood side. I am going to invest in a lot of sandbags and then glue down the flooring with the sandbags on top until the glue has set. I did look at some other engineered flooring at a local retailer, and their planks are also bowed, but since the wear layer is much thinner on those and the plywood layers are also thinner, they are much softer and easier to straighten out than the brand I have (which is 5/8" thick with a 3/16" hickory wear layer).

As far as acclimation, the bowing on mine got worse with time (2 weeks). The planks started at 10% MC and ended at 6% after two weeks in the house (based on my Wagner 205 meter). Either the factory laminated these during wet conditions or they stored the finished planks during high humidity conditions. I don't know. In my case, the flooring did NOT improve with acclimation.

If I decide to glue mine down - how long should the weight stay on top of the wood before I remove it? Does anyone know if Bostiks EFA adhesive is good enough for BR111 wood?

Rudy, you should not be getting wood that reads 10 % right off the bat. Losing moisture is what makes the wood bow.