Cupping

[Pilgrim]

So I've finally started on my floor after having the wood stacked up by the wall all winter. Bought a moisture meter, the pin type, and the wood was showing very low moisture content, if I was reading it properly. Some of it was showing zero percent. I'm using the glossy white moisture barrier, and a little disgusted with the mill work of the flooring I bought. It's a 5' rustic red oak.

So at this point I have a a third of the floor in and noticing some cupping on the board. Thinking maybe too dry when installed and now absorbing moisture? Right now the wood that I have opened up to climatize is showing about 2.5 percent moisture, and my subfloor (plywood) is ranging between 8.5-13. Is that too high a content on sub floor? Or will that be okay since we have the vapor barrier? Is the content too low on the flooring?

Any help will be greatly appreciated.

 

[Dan]

I've never heard of a meter that will accurately measure as low as 2.5%.

What brand and model of meter did you purchase?

 

[Pilgrim]

I've never heard of a meter that will accurately measure as low as 2.5%.

What brand and model of meter did you purchase?

Its an ExTech

 

[Dan]

Which model?

 

[Pilgrim]

Which model?

Oh sorry, M0230

 

[highup]

Mind telling where you live? I'm not a wood guy, but that's really dry.

 

[Nick]

Are you pinning the wood in the correct direction ? One pin behind the other going down the length of the board ..

I agree with Dan ..

 

[happyhours]

That wood is mighty dry . If I'm not mistaken, the wood and the sub-floor should have about the same of moisture content for a good installation.

 

[Nick]

That wood is mighty dry . If I'm not mistaken, the wood and the sub-floor should have about the same of moisture content for a good installation.

With in 2 %

 

[Dan]

To have a moisture content of 2.5% would require conditions of 60°F to 70°F at 10% relative humidity.

To have a board at oven dry, or 0% moisture content would require conditions of 100°F + and less than 5% relative humidity.

These figures are from the USDA Forest Products Laboratory.

 

[Pilgrim]

Mind telling where you live? I'm not a wood guy, but that's really dry.

Powhatan Virginia, just a little west of Richmond.

 

[Pilgrim]

Are you pinning the wood in the correct direction ? One pin behind the other going down the length of the board ..

I agree with Dan ..

Not sure what you mean by "pinning."

 

[Pilgrim]

With in 2 %

Doesn't the vapor barrier make that a moot issue? I'm guessing no. Another factor that I don't think I mentioned is that when we had the water damage they removed some insulation underneath. I was thinking the moisture barrier (using the shiny white paper like kind) would keep humidity out but rethinking that now. Thinking when we go into heating it will dry out and set back down, that's my hope anyway. And by next summer I'll have the insulation back in place (also thinking of doing a conditioned crawl) and a thermostat that will allow me to control humidity in the house better.

 

[Pilgrim]

To have a moisture content of 2.5% would require conditions of 60°F to 70°F at 10% relative humidity.

To have a board at oven dry, or 0% moisture content would require conditions of 100°F + and less than 5% relative humidity.

These figures are from the USDA Forest Products Laboratory.

I ordered the wood around the beginning of the year and it sat in a heated house for several months. The other day while testing some wood it came up zero again but when I got the pins in further and waited it came up. Right now it's coming in at about 4-6 percent., maybe a little higher. The boards with that reading have been fine. What is the moisture content that is prime? I saw the comment about subfloor and wood being within 2 percent, so that's something new to learn.

 

[Nick]

Not sure what you mean by "pinning."

Your Moisture Meter has two pins you stick in the wood .. Correct ? They should be inserted one behind the other going down the length of the board with the grain.. Going across the grain will not give you a true reading ..

 

[Pilgrim]

Your Moisture Meter has two pins you stick in the wood .. Correct ? They should be inserted one behind the other going down the length of the board with the grain.. Going across the grain will not give you a true reading ..

Right. I've been checking in the tongue and groove about center of boards.

 

[Nick]

Just push the pins in the back of the board .. Not the tongue , and groove ..

 

[highup]

Just push the pins in the back of the board .. Not the tongue , and groove ..

...and not at the very end of the board I assume.

 

[Roland]

You are looking at this all wrong. There is no time on how long the wood sets in your home. It needs to get open and acclimate to the RH it is going to be living in. Sounds to me the ones that are reading 6% are starting to get there. I would stop installing until all the wood reaches were it should be. Get your home some where between 35 to 45 % RH and leave it there.

 

[Ernesto]

The wood MC should be at the median historical average of the year when installed.