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Floor Cupping

Posted on 7/24/19 at 2:06 pm
Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 2:06 pm
I just had new hardwood floors installed and they are beginning to cup. This is a pier and beam home. Water does not pool under the house and it has great ventilation. Any ideas on how to fix this. I'm thinking about getting under there with a paint sprayer and coating the underside of the subfloor with a heavy duty water sealant and running a couple dehumidifiers inside the house. The installer came highly recommended and put in the recommended amount of expansion gaps for the new wood. The wood also sat in the house for a month to acclimate. I'm very annoyed.
This post was edited on 7/24/19 at 2:07 pm
Posted by jmon
Loisiana
Member since Oct 2010
9820 posts
Posted on 7/24/19 at 2:08 pm to
quote:

The installer came highly recommended a


I'd be calling him with the quickness. At this point it is his problem to resolve.
Posted by Aristo
Colorado
Member since Jan 2007
13292 posts
Posted on 7/24/19 at 2:09 pm to
Do you have insulation underneath the house? My hardwood from the 1930s starting cupping a few years back when it gets really hot outside. Turns out we had zero insulation underneath the house. Had that installed and now its a lot better.
Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 2:16 pm to
The house has zero insulation underneath. It was built in 1936.
Posted by wickowick
Head of Island
Member since Dec 2006
46267 posts
Posted on 7/24/19 at 2:16 pm to
What vapor barrier do you have between the floor and the bottom of the underlayment? What flooring was removed prior to this flooring being installed?
Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 2:19 pm to
They used tar paper as the underlayment, which I believe is pretty standard. It was just crappy floating floor before with some kind of felt.
This post was edited on 7/24/19 at 2:21 pm
Posted by NATidefan
Two hours North of Birmingham
Member since Dec 2008
36776 posts
Posted on 7/24/19 at 2:26 pm to
I wouldnt rush to install any insulation. At least not bats.

My home inspector told me to pull all mine out because it was holding moisture and could cause mold growth.

That was not a fun job.
This post was edited on 7/24/19 at 2:30 pm
Posted by NATidefan
Two hours North of Birmingham
Member since Dec 2008
36776 posts
Posted on 7/24/19 at 2:37 pm to
Do you have a vapor barrier under the house on the ground? Plastic barrier?
Posted by wickowick
Head of Island
Member since Dec 2006
46267 posts
Posted on 7/24/19 at 2:41 pm to
Felt work fine, did they install a true hardwood floor? Was it prefinished or sanded and finished onsite? If it was not hardwood, was it engineered prefinished wood?

How long did the flooring material sit in the home prior to being installed?
Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 3:36 pm to
This real hardwood flooring (Red Oak). It was sanded and finished onsite and sat in the home for 5 weeks prior to installation.
Posted by vistajay
Member since Oct 2012
2798 posts
Posted on 7/24/19 at 3:51 pm to
quote:

My home inspector told me to pull all mine out because it was holding moisture and could cause mold growth. That was not a fun job.


I had to tear mine out after Katrina flooding had soaked it. It was encased in wire mesh that I had to rip out first, then pull down the water laden insulation on top of myself. My BIL was supposed to help me but got claustrophobic and had to climb out. That was REALLY not a fun job.
Posted by Clames
Member since Oct 2010
18796 posts
Posted on 7/24/19 at 3:54 pm to
How was it installed? Nails? Adhesive? How much room was left for expansion?
Posted by Motorboat
At the camp
Member since Oct 2007
23887 posts
Posted on 7/24/19 at 4:01 pm to
the expansion is not the problem here. Expansion is not going to cause cupping. It is moisture. If applied with glue, the glue could be used as a vapor barrier. OP needs to get the moisture differential between the inside and the outside leveled off or insulate. Likely you will need closed foam cell insulation under the house.

I wish I didn't know all of this...

Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 4:12 pm to
It was nailed in. No glue was used. I'd say they used 1/8" spacers about every 4 feet or so.
This post was edited on 7/24/19 at 4:14 pm
Posted by Motorboat
At the camp
Member since Oct 2007
23887 posts
Posted on 7/24/19 at 4:22 pm to
You are getting moisture in floors somehow, likely from condensation underneath. when you run your A/C, the floors are cold and water condenses on the humid underside. It gets wicked up through the subfloor into the less humid top floors.

You need something to curb this, such as insulation or a vapor barrier. But judging by your username, you probably already understand this.
Posted by ThermoDynamicTiger
Baton Rouge
Member since Jul 2008
1435 posts
Posted on 7/24/19 at 4:25 pm to
Yes, which is why I am going to try a heavy duty water sealant on the underside of the subfloor and caulk the seems along the floor joists. Hopefully, this can lock out the moisture seeping through the sub. Sounds like no one has done this or endorses this idea....
Posted by Motorboat
At the camp
Member since Oct 2007
23887 posts
Posted on 7/24/19 at 4:30 pm to
quote:

Sounds like no one has done this or endorses this idea....


I think because the installation of water sealer on an overhead surface is difficult and caulking the joists will be tedious. But hey, you sound like an engineer and every engineer knows it all.

Seriously though, spray foam is the tried and true way. Dry out with dehumidifiers from both inside and outside before applying. that will requiring sealing off the underside of your house.
This post was edited on 7/24/19 at 4:31 pm
Posted by NATidefan
Two hours North of Birmingham
Member since Dec 2008
36776 posts
Posted on 7/24/19 at 4:39 pm to
quote:

That was REALLY not a fun job.


Yeah, sounds worse than when I did it. I wore a mask and still got sick. Took me two Saturdays and got sick the night after each time.
Posted by ChEgrad
Member since Nov 2012
3754 posts
Posted on 7/24/19 at 6:26 pm to
How bad is cupping? Just barely raised seams?

I installed pre-finished flooring two years ago. The seams raise slightly even though I have vapor barrier and proper gaps. Let wood acclimate also. I just accept it as that is how wood works. My floor installed in 1998 that was finished in place does it slightly also. I can see it, but not really detectable to my feet. My wax finished floor from 1948 doesn’t do it though. Maybe wax is a better finish for moisture equilibration.
Posted by Aristo
Colorado
Member since Jan 2007
13292 posts
Posted on 7/24/19 at 6:55 pm to
quote:

Seriously though, spray foam is the tried and true way.


If you have termite coverage check with the company to make sure they will still cover the damage (shouldn't be any if they do their job correctly) if you use spray foam. Mine would not.
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