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SteveO
Hardwood Floor Gap Forensic Analysis

The house:
2.5 year old townhouse near Washington DC
Living/Kitchen/Dining room approximately 18' X 36'
Hardwood flooring running in the 18' direction/perpendicular to the length of the room.

The issue:
Every year in the Fall, the hardwood floor opens a gap nearly 1/4 inch across the room in the exact same spot.

Builder response:
This is "normal" seasonal change. The hardwood contractor states that this is common in homes.
They did finally agree to bring in a 3rd party inspector. I would like to have good, well thought out questions ready for them.

About me:
I am an engineer and their answer doesn't sit well with me.
I believe this is a subfloor issue.
I have had numerous homes with hardwood and I have never see an issue like this without other contributing factors (subloor problem, division between home addition, etc...)

Am I missing something? Could this be just a coincidence that it happens in this one spot and the builder is correct??

Thanks!

dj1
Re: Hardwood Floor Gap Forensic Analysis

Pursue this issue until corrected. 1/4" gap is not acceptable.

Please report back.

JLMCDANIEL
Re: Hardwood Floor Gap Forensic Analysis

No gaps in my hardwood floors. Suspect that the flooring was not acclimatized before it was installed.

Jack

MLB Construction
Re: Hardwood Floor Gap Forensic Analysis

this makes sense to me. i would assume that the flooring was installed improperly. my best guess is that the flooring contractor installed the flooring from one wall towards the middle and from the other wall towards the middle. this would cause the area where the gap is to not be properly fastened. therefore during the dry times of the year all the shrinkage would occur, or appear to occur, in one place. an easy way to assess this would be to see how deep the gap is in the flooring. if the gap appears to go down about 1/4" to 3/8" you would be seeing the tongue of the flooring. if the gap appears to go down about 3/4" that would mean that they put down the floor from the outside walls towards the middle which is dramatically wrong. can you post a picture of the gap? one that shows the whole gap and one that's a close up of it?

Sombreuil_mongrel
Re: Hardwood Floor Gap Forensic Analysis

my guess is this: there is a clean break in the subfloor there, and none of the plywood runs across this line, which is why the halves of the room can move independently concentrating a lot of movement at one plank seam. This may be out of necessity; the floor joists could also change direction at that point, or it represents the line of an addition or the removal of a wall. In any of those cases, additional underlayment, 3/8" plywood at minimum, should have been put over the broken subfloor, unless the plywood could have been taken up and new subfloor put down with staggered joints all the way across the space.
The problem is that only the occupant will see this as a problem, because it does not represent a safety issue, just an aesthetic one.
Casey

MLB Construction
Re: Hardwood Floor Gap Forensic Analysis
Sombreuil_mongrel wrote:

my guess is this: there is a clean break in the subfloor there, and none of the plywood runs across this line, which is why the halves of the room can move independently concentrating a lot of movement at one plank seam. This may be out of necessity; the floor joists could also change direction at that point, or it represents the line of an addition or the removal of a wall. In any of those cases, additional underlayment, 3/8" plywood at minimum, should have been put over the broken subfloor, unless the plywood could have been taken up and new subfloor put down with staggered joints all the way across the space.
The problem is that only the occupant will see this as a problem, because it does not represent a safety issue, just an aesthetic one.
Casey

that's definitely another possibility

Mastercarpentry
Re: Hardwood Floor Gap Forensic Analysis

My first thought too. Anytime you use sheet goods that join, you must offset the laps to prevent such as this. Even when joist directions change, you can arrange the sheet and joist layout to lap and you should- standard good building practice.

As to the builder's comments, yes- hardwood flooring may move a total of 1/4" across a given room, but not all in one place. That natural movement should occur fairly evenly across the entire floor so that it's hardly noticeable. If it's occurring in one spot alone then somebody did something wrong either with installing the hardwood or with whatever is underneath it. I would be insisting on having the floor pulled up to ensure that the subflooring is correct before it is relaid, and I'd do the research on the product manufacturer's recommended procedures on all parts of this to be sure they are followed correctly this time.

Phil

KShenefiel
Re: Hardwood Floor Gap Forensic Analysis

I suspect the hardwood might be an engineered floating floor with a hardwood surface rather than traditional solid hardwood. With floating floors the boards are glued or snapped to each other but aren't connected to the subfloor. All the seasonal movement is designed to occur at the perimeter of the room where it will be concealed by the baseboard. If something is anchoring the floor toward each end of the room the tension of the fall shrinkage could have caused one of the tongue and groove joints to fail. Like a chain only the weakest link will open up.

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