I need some advice about our newly installed wood flooring. We have multiple issues with hollow boards and movement and would like to know if the entire floor needs replacing or if the fixes our flooring contractor is suggesting will suffice.

To give you a little bit of background, last year we removed the carpet and tile in our home and laid down new engineered wood. That install had issues from day one and left us with numerous checked boards that ultimately required complete removal. Fast forward to this year, we had a different company come in to rip up the bad wood flooring and install new. During the preplanning stage we notified them that the previous company did not prep the concrete in any way and that we were unsure of the condition it was in. They were also made aware of the numerous hollow sounding boards throughout as well as the cracked boards that were the cause of floor failure.

We had approximately 1900sf of Grand Pacific, ½” engineered wood installed on a concrete slab using Mapei adhesive and are in the dry climate of Arizona.

During the first day of install, we were told that the concrete was fine and that they did not need to prep it in any way. Prior to them completing the entire house, we noticed that while walking in some areas, you could feel the boards move. Upon further inspection, the areas in which this occurred corresponded with hollow sounding boards. So, since we had already gone through a bad experience once, we went through the entire house making note of all the hollow sounding boards, in which there are hundreds.

When the flooring installers saw the massive amount of tape on the floor depicting the hollow spots, we were told that the spots were cosmetic and that the boards were secure, except for a few areas where the boards moved. Instead of addressing all the hollow boards, the plan was/is that the large areas of moving boards are to be ripped out and replaced and the smaller areas were to be injected with epoxy. Well, the epoxy was done in three test areas, and it made no difference other than reducing the hollow sound by about a 1” perimeter around the injection site. Their reasoning was that the epoxy could not get through the different channels of adhesive underneath the board, so it could not spread.

The remaining solution was to replace all the moving boards. Some of which have been replaced, with problems of their own like lifting, but the majority has yet to be. To give you some idea of the amount needing replacement, a 14 x 14 room has already had a dozen boards replaced and there are still 10 more that they haven’t gotten to yet. This is just a sample because each room in our house is this way.

My questions are as follows; 1) how many hollow spots are too many? 2) should there be any movement or spongy areas in engineered wood that's glued on concrete and 3) is replacing this large amount, one board at a time, acceptable or should the entire floor be removed and replaced again after a proper self-leveling prep?

Any advice is appreciated and I thank you for your time.

A wide plank floor requires a flat surface for good results. Hollow sounds do not equal a bad installation. Some movement is acceptable. Epoxy used for spot repairs is an acceptable solution. This may be one of the first wide plank installations of this contractor. After the contractor makes as many repairs as they feel necessary, you may call a certified inspector. There may be an NWFA certified inspector in your area. They are not free.

Thank you Pete for the reply, I appreciate it.

This flooring installer has been in business for many years, and actually put wood flooring in our other house 12 years ago without any issues.

We’re very familiar with the flooring inspector and that process, as we had to have that done last year with the previous wood floor install.

I realize that hollow sounds do not necessarily equal a bad installation, but how many are acceptable? I am not exaggerating when I say hundreds. There is close to two hundred in one room alone. If the manufacturers warranty does not warranty the hollow spots, then what happens if those areas become an issue later on?

I’m curious about the epoxy spot repair as well. What is an acceptable amount for that? It would seem that if all your boards had holes drilled into them, that would void your warranty as well.

To add injury to insult, they verbally told us that they were aware of areas that were not even and that they used more adhesive in those areas to level it because doing it any other way would be too expensive. One of the guys even stated that the area looked like this, and moved his arm in a motion like a roller coaster. They replaced some of the boards in that area, but any straight stick wobbles like a teeter totter when you place it on there.

They are sending someone to reevaluate the work tomorrow after offering to give us our money back (but not all) and leaving it as is. Both parties are clearly frustrated, but am I being too unreasonable to think that I deserve a quality job?

What's the coverage look like on the back side of pulled planks?
Also which Mapei adhesive and size of trowel.

Hi Stephen! The adhesive is Mapei Eco 980. Unfortunately, I don’t know what the back of the removed boards look like and I don’t know the size of the trowel. If there was a way to post pictures on here, I have a picture showing the size used while replacing the boards, but not during the initial install.

I'd max out the trowel size that's on the chart.
Wider longer planks need more glue and weight.
I was doing a 10" wide x 8 ft 3/4 " plank and used about 10 -5 gallon buckets of sand to weight it down.
Course there's always the obvious slab surface irregularities I grind down, plus patching.
Another problem is the concrete surface profile that should be at least a csp3 at least.
The old glue should be removed from the surface to bare concrete.
Send pics

Let me reiterate that last statement.
If your doing a complete redo take off all the adhesive residue.
Glue sticks better to clean concrete than old adhesive.
Especially if using a different adhesive as many are not compatible.
And some won't even stick to vinyl.
I'm usually down to concrete when doing plank replacements as well.

Hi Stephen!
Thank you again for your replies. There was no prep work done to our cement slab prior to the installation, which seems to be the core issue.
We went ahead and had our floor inspected, and was told that it is one of the worst installations the inspector had seen in a very long time. The word he kept throwing around was "egregious".
We are exploring our options at this point, but wanted to thank you for your time.
Melissa