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no expansion gap in hardwood floors

Posted by threeberries (My Page) on
Sat, Jan 26, 13 at 23:00

In my new construction home, they have just installed unfinished 5" solid maple on the 2nd floor, and haven't gotten to the 1st floor yet. On examining the work, I see that the flooring goes right up to the baseboard trim, not under it. There is not even a millimeter of space between the floor and the baseboard; it's that tight. The baseboard only has about 1/2" of space under it, and since the floor is 3/4" thick hardwood, it can't fit under the baseboard. They've known for a long time that 3/4" floors were going in. It seems to me that either they should have installed the baseboard trim with 3/4" under it to accommodate the floors going underneath it, or the baseboard should have been installed after the floors, on top of them -- in either case with a gap between the floors and the walls so the wood floors have room to expand. There is NO gap because the floor juts up against the baseboard.

It's especially important to install this flooring correctly since it's maple (unstable), wide plank (5"), winter and in Massachusetts where the humidity and temperature vary wildly throughout the year. I had previously asked my builder if they checked that the floor moisture was within 2% of the subfloor (guidelines for wide plank) and he never answered. Before that I had asked how they determine a floor is ready to install, and he said they let it sit out for a week. He usually installs 3" red oak, but does use professional flooring people to do the floors.

The flooring manufacturer states that the installers must follow the NWFA guidelines or the warranty is void. The NWFA guidelines state no more than 2% moisture difference, and expansion space (3/4") is required. The temperature in the house is 61 (heat is on) and the humidity is 28%. The floor is tongue & groove and I assume nail-down. I see different opinions on whether nail down needs expansion near walls, but most seem to be on the expansion-is-needed side (including the NWFA). Others say the boards can't expand as a whole if they're fixed to the subfloor.

There's also been wet work (tile installation & grouting) going on while the wood is acclimating and getting installed - I understand that's not supposed to happen either.

I'm extremely worried about the lack of expansion gap, and whether in general they're following proper procedures (e.g. the 2%). Before I raise this issue with my builder and possibly my lawyer, just wanted to check that I'm understanding the requirements correctly and I'm not missing anything.

Thanks so much for your help!

This post was edited by threeberries on Sun, Jan 27, 13 at 1:21

Follow-Up Postings:

RE: no expansion gap in hardwood floors

You're wise to be concerned. If your builder doesn't give you any satisfaction after pointing out these legitimate concerns, I suggest you write something up and have him sign it acknowledging that he's been informed. Maybe that will convince him of the seriousness of the issue and spur him to action.

RE: no expansion gap in hardwood floors

Where do you live? Humid summers?

If the boards were installed tight, at 28% humidity, they could cup even with adequate gaps at the edge, when the humidity rises.

RE: no expansion gap in hardwood floors

Thanks for your responses. I live in Massachusetts, and yes the summers are humid. (And very dry in the winter.)

So I talked with my builder about the fact that the installation doesn't have expansion gaps, doesn't follow NWFA guidelines, and therefore voids the flooring manufacturer's warranty (limited lifetime structural warranty). He said he's been installing floors this way for 30 years and has never had a problem. I wasn't really sure what to say to that. He's an honest, straightforward guy so I have no reason to believe he's misrepresenting his experience. I know he mostly installs 3" red oak so I'm not sure how much he's worked with with maple and wider planks, but I forgot to ask.

My builder says he's occasionally seen contraction issues, but never expansion problems. (The floors look relatively tight to me from plank to plank, but I'm not an expert.) My stair builder, who was standing there during the conversation, said that maple doesn't normally expand much, but it contracts.

My builder says he started off using the baseboard trim to cover the gap but people kept complaining about the gap (don't understand that one) so he just started running the floors right to a lower baseboard. The irony is that we paid a lot of money for our baseboard (especially the flat stock) but if we knew they'd be purely decorative we wouldn't have gotten them! So we probably could have saved $1000.

My builder provides some kind of warranty where he'll come fix any problems, although I'm guessing that only lasts a year, but that should be enough to see any cupping or buckling. If the floor cups, and my builder fixes it by sanding and refinishing, does that permanently fix the problem and then it looks great? I'm wondering if you sand cupped boards will they lie flat in the winter and gap, and now you have the opposite problem.

And what about having no manufacturer's warranty? Is that nuts or so unlikely we'll need it that it's not a big deal?

I have almost no time on this - I'm backed up against a wall (apt metaphor!) because we have to close really soon, the 1st floors are getting installed any day now, the seller is trying to make us pay lots of extra money for a delayed closing that is their fault, and we are almost up against our rate lock expiration date which would cost us $1000 to extend. So.... I'm not really in a good position on this one and am wondering if I just leave it and hope for the best.

Thanks so much for your help!

RE: no expansion gap in hardwood floors

If you keep the humidity in your home at a constant chances are you will be okay. But sometimes the unexepected happens.

If he comes back and has to sand due to the expansion issue it wont be a cure all for life. Just until the next time something else happens.

Really look at the fine print on your warranty. They have really strict guidelines on what constitutes a valid claim. A lot of people get burned buying a product solely because of an advertised warranty.

If you are still really concerned about the planks being tight one solution would be to cut a sliver off each plank. Its a lot of time but a fein saw is a good tool to use to make plunge cuts. Its not ideal but will work.

RE: no expansion gap in hardwood floors

"unfinished 5" solid maple"

Is this tongue and groove flooring with individually nailed planks?

There is nothing about that type of floor that need 3/4 of an inch for anything.

RE: no expansion gap in hardwood floors

Yes, it is tongue &groove individually nailed. Does that not expand?

I'm not planning to keep the house at constant humidity. I'll use a humidifier in winter but use a/c in summer only when it gets too hot - I just dont like too much draft or dryness for health reasons.

RE: no expansion gap in hardwood floors

Although the book says to provide an expansion space for solid flooring, I have seen many a solid wood job cut net fit to vertical obstacles in suspended wood floor assemblies that performed fine with no problems with expansion, compression damage or buckling.

Of course, they were over basements. If your floor is over a crawl space, I would be concerned. If it's over a crawl space, then you need to do moisture control in that space.

RE: no expansion gap in hardwood floors

"Does that not expand? "

Each and every strip expands and contracts separately.

The gaps open in the winter when the humidity is low, close in the summer when it is high.

Strip floors do not change appreciable in length along the boards at all (so the two 'ends' do not need a gap to speak of) and only one of the edges even moves towards the wall unless it was laid with a double groove piece starting in the middle of the room.
A double tongue means neither 'side' moves towards a wall.

Engineered floors that are glued together and have NO expansion joints that can move between the pieces behave as a single large piece of wood.
Since many of them are plywood style construction (cross grain layers glued together) THEY move in every direction, sometimes by large amounts in larger rooms.

RE: no expansion gap in hardwood floors

Thanks everyone for your feedback! My floors are over a basement. (Or 1st floor.)

All the flooring is installed now and we're closing soon, so I'm going to keep my fingers crossed. I'll post again to this thread in about 9-12 months and provide an update on how it turned out in case anyone else finds themselves with similar questions.

RE: no expansion gap in hardwood floors

If it moved anything approaching 3/4 of an inch it would tear the nails out.

There is still some skill to installing strip flooring.

Let it acclimate for multiple days out of its bundles and spread out where it will be installed.

Tighter in high humidity (it is going to shrink), looser in low humidity (it is going to expand).

Strip floors that are to tight for the moisture content at install can buckle up and pull fasteners part way out.

The humps then decrease when the humidity falls.

Most of the hump will disappear.

Trying to face nail (or even screw) the area will not usually work.
The forces generated are larger than the fasteners and/or wood can take.
Splitting is not uncommon.

You have to remember that if you have 5 inch wide strips 10 feet wide you have 24 strips of wood.

If each one move 1/32 inch from damp to dry, the total movement you have distributed is 3/4 inch.
It only sows as the joints between the strips opening and closing by 1/32 inch though (and yes it is probbaly off by 1/32 since 24 strips only have 23 joints).

RE: no expansion gap in hardwood floors

We have just installed engineered maple nail install. The contractor left no expansion gap at all. It's been about a week or two and half of the floor is buckling!!! How can he fix this? I asked him and he just sas he will face nail few of them. I do t believe this will fix the problem

Please help! If anybody had experience with this please tell me what do to

Thank you

RE: no expansion gap in hardwood floors

It's been about a week or two and half of the floor is buckling!!! How can he fix this? I asked him and he just sas he will face nail few of them. I do t believe this will fix the problem

He fixes it by removing it, buying new flooring, letting it equilibrate to the house as specified by the manufacturer, and installing it the way the manufacturer specified.

Face nailing a few of them will just shift the bucking to new spots, and facenailing them all will give you nail pops that rip your feet open.

RE: no expansion gap in hardwood floors

A flush cut saw can create the missing gap and then your floor will be able to expand and contract at will. If your contractor does not know about a flush cut saw or how to use it to correct his mistake, then you need to find someone who does and then make your contractor pay for the cost to repair this job. After all, your contractor is required to guarantee his work to be free of workmanship defects for a year in most jurisdictions.

RE: no expansion gap in hardwood floors


Would love an update on your floors! How did they do over the summer?

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