We are having hardwood flooring installed and are having an issue with acclimatization. Our subfloor is at 9-9.5%. The installer wants the new flooring to be within 2% for the install. We opened the box ends of the new flooring, Acacia, and it was at 6.5%. He said it should get up to at least 7.5% before we install it. We have multiple moisture readers and the installer checked with his. All agreed our house stays between 40-50% most of the time with a few dips down to 36-53%. Temp stays between 68-71 F. The acacia has been open in our house for 5 weeks now. It has lowered from 6.5 down to 3.5%. Why is it going the wrong way? The installer is stumped. He left his moisture monitoring units in the house for a week and it showed a humidity range of 42-51% and temp range from 68-70F during that week. During that week the acacia lowered from 4 to 3.5%. Every chart I look at says the wood should be around 8-9% in those conditions. We have tried multiple pin type moisture meters and had other installers come out with their equipment to double check and they all agree within about .3-.5%.
Acclimatization issue - new flooring moisture going down instead of up.
- Thread starter wori
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Different species of wood will read differently on a moisture meter. Some moisture meters have ‘built in’ corrections for different wood species, others don’t. Is there any adjustments or calculations that are being forgotten about when trying to figure out the MC of your acacia?
Thank you for the reply. Yes, the meter has a setting specifically for acacia. Using the same meter and settings the Acacia has went down from an average of 6.5% to 3.5% in a room that stayed mostly around 45% humidity and 70 degrees.
Climate controlled environment? 3/4” plywood sub floor? Is there a damp basement or crawl space under the area to be installed?
If the answers are yes, yes, and no and the flooring has been in the room opened for 5 weeks I would say it should be fine to install. Can’t think of any reason why the meter readings are so wacky except for what CJ said. 3.5% seems pretty dry? Maybe try racking out the boards and let them sit for a week if that’s feasible.
If the answers are yes, yes, and no and the flooring has been in the room opened for 5 weeks I would say it should be fine to install. Can’t think of any reason why the meter readings are so wacky except for what CJ said. 3.5% seems pretty dry? Maybe try racking out the boards and let them sit for a week if that’s feasible.
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I had a job years ago that had a floor that had been peed on over the years by pets. It wasn’t wet when I stuck my moisture meter in it but for the life of me I couldn’t get an acceptable reading. Ended up ripping out and replacing all the affected underlayment.
I’ve also seen plenty of houses with out a vapor barrier in the crawl space. That makes a big difference as to what your subfloor reads.
How long are the pins on the moisture meter you’re using. My first moisture meter had pins that were maybe 1/16”. Kinda hard to get an accurate reading with such short pins. That came back to bite me a time or two so I got a better moisture meter. My current pins are maybe 1/4”. Gotta keep in mind that while I can easily bury the pins in a soft wood there’s no way I’m those pins in 1/4” on acacia.
As far as the reading go and species correction, you generally have to take the reading you get and alter it somehow cus there’s no way your meter knows what kind of wood you stuck it in. As you can see with my species correction chart almost all readings will be higher after you do the correction. Interestingly enough my chart doesn’t have a correction for acacia. Self correcting meters require you to actually change the setting on the meter for them to self correct. You would have to have the meter set correctly to measure the subfloor then change a setting in the meter to measure the acacia otherwise whatever reading you get will be incorrect.
Almost forgot the most important part, if your battery is dying you will get incorrect readings. I always keep a couple new batteries with me. If I get a reading that just puzzles me I’ll switch out my battery just to confirm that I’m getting accurate readings.
I’ve also seen plenty of houses with out a vapor barrier in the crawl space. That makes a big difference as to what your subfloor reads.
How long are the pins on the moisture meter you’re using. My first moisture meter had pins that were maybe 1/16”. Kinda hard to get an accurate reading with such short pins. That came back to bite me a time or two so I got a better moisture meter. My current pins are maybe 1/4”. Gotta keep in mind that while I can easily bury the pins in a soft wood there’s no way I’m those pins in 1/4” on acacia.
As far as the reading go and species correction, you generally have to take the reading you get and alter it somehow cus there’s no way your meter knows what kind of wood you stuck it in. As you can see with my species correction chart almost all readings will be higher after you do the correction. Interestingly enough my chart doesn’t have a correction for acacia. Self correcting meters require you to actually change the setting on the meter for them to self correct. You would have to have the meter set correctly to measure the subfloor then change a setting in the meter to measure the acacia otherwise whatever reading you get will be incorrect.
Almost forgot the most important part, if your battery is dying you will get incorrect readings. I always keep a couple new batteries with me. If I get a reading that just puzzles me I’ll switch out my battery just to confirm that I’m getting accurate readings.
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Another thing I like to do is to check the MC of something in the garage. A stud or in my case a workbench. I’m in Phoenix, it’s pretty dry here.
So in summation for a 3.5% MC to be accurate it would have to be pretty much stored in an oven set to around 300° I suspect….
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That is very much my thoughts, but it's been tested with 3 different meters owned by different people by two different brands and they all agree fairly closely. It's boggling my mind.
Quarter inch uninsulated pins. Mini-ligno X/D was one of them. I tested several other pieces of wood in the house and they are around 6-7%. Out in garage they average 8-9%.
I pulled several boards out of the acacia flooring stack and tested them. Some are down to 3.4% and a few as high as 11%. Most are 5-6.5%. I can test those repeatedly with different meters. They are prefinished, it's making me wonder if the finish or treatment is doing something wonky to the readings. I can't imagine a board dropping from 6.5 down to 3.4% in a pretty average house environment.
I’d be more worried about the ones reading 11%.
My guess is for whatever reason you’re getting false readings.
Personally, if it were my house, and they’ve been acclimated for 5 weeks, and there’s no damp basement, I’d roll the dice and install them.
Customer’s house, I’d let someone else make the call.
If you’re worried ask the manufacturer what they want you to do? Send it all back?
My guess is for whatever reason you’re getting false readings.
Personally, if it were my house, and they’ve been acclimated for 5 weeks, and there’s no damp basement, I’d roll the dice and install them.
Customer’s house, I’d let someone else make the call.
If you’re worried ask the manufacturer what they want you to do? Send it all back?
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