Hi – We could use some advice regarding solid oak (t&g) flooring that we had installed in our living room a few months ago. Originally when we discussed installation of the floor with our contractor he said that he would be nailing the boards to the sub floor (which is in good flat condition. Original wooden planks 1930s I believe), but after speaking with his floor guy they decided to go with adhesive. As we had not moved into the house at the time of the installation it was all done in a room free from furniture and foot traffic. We later learned that the floor had been installed in a floating manner rather than the boards being secured to the subfloor with adhesive. The floor looked okay when we first moved in, although we did notice some variances in the spaces in between the boards (but felt this was within an acceptable range). However, a gap started to appear down the middle of the floor which ran the entire length of the room (about 15 ½ feet) just over a month after the installation of the floor (and a month after moving in). This gap has now expanded to just under ½ and inch and we are unable to see any adhesive material on the exposed tongue of the planks. Needless to say, we are very upset by this occurrence! We contacted our contractor and asked him to come over and take a look at this large gap in the floor. He came by a few weeks later and brought his floor guy with him as well. They both seemed stumped as to why this would have happened and said that neither of them had ever seen anything like this before. They checked each end of the flooring (and the small hallway which was also installed with the flooring) and assured us that there had been no noticeable “shifting” of the entire floor. I had suggested that the gap might be an accumulation of movement (contracting) of the entire floor, but they seemed to dismiss that idea. We did learn on that on this visit from our contractor that his “guy” only applied adhesive to the underside of each tongue and none was applied into the grooves. Technical information: solid oakn125x18mm oiled wood, underlay used was Vitrex 5 Star Sound Reduction Underlay with 5mm floor levelling properties and impact sound insulation to 20dB. Excellent thermal insulation.
So, we could really use some professional help with this matter. Before seeing the gap they implied that it must be our fault for spilling something on the floor or cleaning it with something too damp/wet. Neither of these things are the case. We believe that this has occurred due to poor installation by themselves. The more we read about solid wood flooring the more we have learned about it….such as how much more it moves than engineered wooden flooring and that most (if not all) sites recommend that solid wood floors need to be fixed to the sub-flooring, either by nails or adhesive. Any help or advice that you could provide to us in order to help us in our quest to find out why this happened and to help educate our contractor so that we can have the flooring re-installed properly would be very much appreciated.
Thank you.

A few things:

1) it is actually correct to put the glue on the underside of the tongue during a glue-together floating applicaton. This prevents excess glue from coming up through the boards, and excess glue in the groove which would might push boards apart.

2) however; solid hardwood is not typically floated - glue down or nail down is the preferred method. Engineered or laminate floors can be floated with glue-together or click locking systems. I'd be very concerned that you had agreed on nail down, then glue down, only to have them install it floating instead. If you paid more for these better methods but did not get them, you got ripped off, and should demand a Re&Re of the whole floor with the proper installation method followed.

Contact the manufacturer and ask if they can send an inspector to verify if the wood was installed according to their requirements. If it has not been (and I suspect that's the cause of the failure) then the contractor is on the hook to replace the floor

Thank you for your response. We did contact the manufacturer through the website that we bought the wood from and like you said, their response was: the fitter must fix the floor to the subfloor, either gluing (onto concrete) or nailing (onto ply or existing floor boards).

That is good advice about the contractor changing from nails to adhesive. We will follow up with them about that!

Can I just ask a few follow up questions? I do see that some people have tried to float solid wood floors but there seems to be special ways that they would do this (like purchasing foam underlay with adhesive on one side, that presumably you would affix your hardwood floors to...and so the floors would "float" affixed to the underlay but not the actual floor boards. I guess my question is, if they were going to go against the norm and try and float a hardwood floor, do you know of any special things that they should have done in order to increase the success rate of trying such a method (such as special underlay)?

Also, why do you think that such a large gap has appeared in our flooring? Do you think that it is from accumulative shrinkage causing pressure to build progressively up across the floor and that the gap was just caused by a weak link in the gluing?

Hopefully those questions make sense. Thank you again for your help with this matter!

I'd say it's likely to be the opposite. You use metric numbers and the term fitter. UK? Has the weather been bitter cold with dry heating? That creates shrinkage. Maybe that seam had very little glue used and it separated. Like Kris, said solid hardwoods are rarely floated. Some companies bring them to market but inevitably they all fail.

When the humid months come back, assuming you have that type of climate and don't use climate control, I can see some major issues with the floor expanding and practically 'exploding' with a plank nearly 5 inches wide.

A do-over with the cost going to the installer would be my answer, unless I'm missing something.

Thank you so much for your advice and help in understanding what happened. This has truly turned out to be a nightmare. But hopefully things will get better!

Yes, I am an American living in the UK. Hopefully it is okay that I posted here. Just needed to hear from people that I trusted.

Yes, it has been quite cold here and the radiators produce dry heat. Doesn't get too humid here, as we are in the north. But your advice on heat/summer issues was enough to scare me! Lol.

We will be pushing for a do over with the floor installers.

Just out of curiosity, is oak a good choice for flooring (as far as movement and adaptability to temperature?)? We like the oiled and brushed look but there is not as much of a choice here. Every time I find a floor that I fall in love with it seems to be from the U.S. Really some spectacular and beautiful wood to choose from!!!