I live in Calgary, AB Canada. I am planning to install 3/4" x 3.25" Brazilian Cherry. I just rented a mini-Ligno DX/C to measure the moisture content of my subfloor and my wood. All readings are 4.7%. Even in air, it reads 4.7%. Thus, I expect that is the minimum reading of this meter and that the moisture content is indeed lower than 4.7%. I've tried various woods in my house (even in the basement). All are 4.7%. In my unheated garage (currently around freezing), the plywood is around 7%. So I suspect the meter is working.

My relative humidity is running between 30 to 42% during the past month while I have let the wood acclimatize. Inside temperature at 22 C (72 F). During the past week, it has probably averaged 32 to 35%. I don't trust my RH meter very much. For that matter, I don't trust any RH meter. When I go to a store that has a dozen of them hanging on the rack, they seldom agree. I do know that I can't add any more humidity because my windows sweat too much when the outside temperature drops below -20 C (-5 F). I see these temperatures fairly frequently. I have a 2nd RH meter and the two are generally within 5%. That still doesn't give me a lot of confidence that these readings are correct.

Can anyone tell me what moisture content I should expect to measure in my wood given these parameters? Do the numbers make sense? Do you think I'm OK to install?

Thank you

I think your kinda low on rh right now.

http://www.climatetemp.info/canada/calgary-alberta.html

Cool website link! Thank you. I heat my house for 7 or 8 months a year, so I'm not sure if the relative humidity numbers in this website are relevent? Perhaps the numbers in May through September are relative because I may not be heating my house in those months. If I believe those numbers, then I have to believe that my RH meter is reading low by 5 to 10% (just a guess).

If my wood is at less than 4.7%, what does that mean my RH is right now?

Thank you

I have a http://www.ambientweather.com/lidxd1miforw.html minilogo like that I won for getting all my inspections in by the deadline. I don't trust it a bit. It never reads like my professional tramex pin meter does. I also trust my professional thermo-hygrometer, you can breathe near it and it will go up within seconds.

Professional equipment = exacting results.

Thank you. The link to the meter looks the same as the one I've rented!

I found this website:
http://www.csgnetwork.com/emctablecalc.html

Can anyone verify that this website is accurate? If I my wood is under 4.7%, then it is suggesting my relative humidity is no more than 21%. I suspect this is possible. I say this because I know my windows are on the verge of sweating at -20 C (5 F), and I know that the recommended interior humidity level at those temperatures is 20% to 25%, so it makes sense. Also, the humidistat for my humidifier seems to indicate a lot lower RH than either of my electric ones. It is in the 15 to 20% range, so perhaps it is the only RH meter that works in my house.

Would anyone be scared to install this hardwood given the information I've supplied? It seems like the wood has dried out similar to my subfloor. Unfortunately, I can't tell if they are within 2% of each other, but it seems likely given that it is doubtful my subfloor is less than 2.7%. To be less than 2.7%, the relative humidity would need to be less than 10%. I doubt that is the case. The wood has been in the individual rooms for a month now.

Thank you

I got this pdf I'll try and copy for plywood moisture content.

Use your pin moisture meter to measure your wood flooring material. Take multiple
measurements and average the results. The NWFA recommends measuring the moisture
content of 40 boards for every 1000 square feet (Do not just measure the ends of the
boards that are on the top of the pile). The boards should be selected provide the most
accuracy survey of the moisture content. When using a pin meter it is important that you
push the pins in as close to their full length to ensure good, consistent contact with the
wood fibers. Using an insulated pin allows you to penetrate to whatever depth is
appropriate for that thickness of wood.
Use calibration charts supplied by you meter manufacture to adjust the readings for your
sub floor and hardwood finish. Some meters have built in species correction factor that
may be utilized.
The APA evaluated the equilibrium moisture content of structural panels. The results
indicated that the moisture content of plywood and OSB at a given relative humidity is
lower than the published values for solid wood. The APA data below is based on an
absorption cycle at a temperature of approximately 70°F. (APA Form No. TT-028A
December 2006)
Use the EMC chart below to calculate the appropriate moisture content of the sub floor
and wood finish and then check against the actual reading you have recorded.
The NWFA recommends maximum difference between the sub floor moisture content
and finished wood moisture content of 4% for strip flooring and 2% for plank flooring.




Oh darn, the EMC chart will not copy.

Oh here it is on page 12

http://woodflooringedu.org/archives/dow ... meters.pdf

Thank you,

I haven't sampled 40 boards, but I have probably sampled a dozen. I was opening up the end of a box, and pulling a board out from the center of the box, so I could sample it at close to the center of the box. I didn't get anything that read a moisture content over 4.7%. It seems pointless to sample a whole bunch more when the meter simply can't resolve the moisture!

The chart showing the differences between OSB and solid wood is really interesting. Basically it says that even if I could measure the moisture content of the wood properly, in a fully acclimitized setting, the OSB would be at least 2% lower than the solid wood. Thus, no matter what I do, I will have to install the wood outside of the manufacturer's specification of a 2% difference. That's crazy!

The OSB or plywood can be lower than the hardwood just not higher than 2% in MC When your in that low of a zone, how much drier can it get? Make sure you use at least 15lb roofing felt Maybe 45lb in your case.