Correct % humidity for wood floor?
Streamline
| Posted in Construction Techniques on
I am going through my first year cycle on my hardwood floor (engineered 3/4″ boards, 7″ wide planks). I have a humidifier attached to the furnace to regulate the humidity of the house, thus benefiting the wood. During the summer, I notice that the humidity reads 70%. As winter begins to set in the NW, I am reading 50% today. What is the proper range of humidity I should target for the house to keep the wood floor happiest? I have PEX radiant piping in gypcrete below the wood if it matters any.
Edited 10/13/2009 10:41 am by Streamline
Replies
"I have a humidifier attached to the furnace to regulate the humidity of the house, thus benefiting the wood."
To help the wood, you need a DE- humidifier
People are most comfortable at about 40% humidity or so, while the home's materials are more comfortable at 20% humidity
Moisture content is the important thing for wood floors and your's is likely OK with heat under it, though that was probably not running in summer when you had 70% RH in the air. I would expet to see some movement and shrinkage as you move into winter adding heat under while the air dries, so you will want the humidifier running in winter to keep it up to 40% Is there a humistat to control automatically?
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
I kinda like it at 50% humidity because it is close to 70% summer - resulting in less change for the wood. The humidistat has a knob next to it, I assume to regulate the % humidity. I may just leave it alone if it keeps it at 50% through winter. Curiously, you mentioned that this is relative humidity. I thought it was absolute because the wood can careless what the amount of moisture is relative to temperature (RH), it would care only the amount of moisture available in the air - correct? Just curious.
moisture content in wood is only indirectly connected to that in air.
I mention relative humidity because the actually amt of moisture in the air varies with temperature. Summer RH at 70% in 76°F temp can have twice as much moisture as winter RH of 50% in 68°F temps.That is all moisture in the air, while the moisture content in wood is an absolute measured by percent of weight.When the air is relatively wet and the wood is on the dry end of the scale, the wood will absorb moisture from the air. Conversely, when the air is relatively dry, and the wood is on the damp end of the scale it will give up moisture to the air.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
How cold does it get in Edmonds? Generally you shouldn't humidify above about 40%, and that number needs to be reduced somewhat as the outside temperature drops. Depending on how tight and well-insulated the house is (and how thermally efficient the windows), you may want to drop the humidity roughly 5% for every ten degrees below 20F.
My house is at the Puget Sound with the water regulating the coastal temperature quiet nicely. Temp mostly 35-40 degrees with couple of weeks dipping below freezing. What is Below freezing. What is the danger of keeping the humidity higher during winter?
"What is Below freezing. What is the danger of keeping the humidity higher during winter?"Here in the States, below freezing is a temp of less than 32°F.
I hear that Canuckians call it 0°C. Regadless, that is when water losses its liquidity and becomes a solid that can make you land on your butt;)High humidity in winter means that about a dozen people will suddenly be asking the question here at BT, "Why are my windows getting all covered with water or frost?"
In some homes, they will also start seeing what appears to be roof leaks, but is really condensation in roof/attic/ceiling assemblies
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
High humidity in extremely cold weather can result in condensation in the cooler parts of the home. Most obviously on windows, but also in cold corners, kitchen cupboards, inside walls, etc.Additionally, there's really no point in maintaining humidity above 35-40% -- the house doesn't need it and generally neither do the people.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
most makers of hardwood we do business with say r.h. of 50-55 % RANGE WHICH IN HOUSTON MEANS AIR CON.ALL YEAR ALMOST
I'm guessing that's the max humidity? (But even that is unrealistic.)
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Well now, Houston IS a bit humid naturally
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
So, higher humidity is good for the wood floor because the wood does not contribute moisture to the air and risk shrinking. Is this a fair statement? I can keep the air as moist as my house can handle without creating condensation in windows or other areas. Is this a fair rule to use in a wood flooring house like mine?
Within reason the floor does not care what the ambient humidity is. What was the moisture content of the flooring when it was installed compared to the humidity in the house? If the house humidity was around 50% then the flooring should have been around 9% (EMC). If so, and you have adequate expansion room along the perimeter you should see no problem in the flooring. If the relative humidity goes down the flooring will shrink, possibly exposing the edges; it depends on your edge treatment (baseboard, shoe molding, etc). The floor will like it best if the humidity swings through the year are kept to a relatively small range.
Sorry, but I got to say if I fretted this much about how to keep wood floors happy then it's the wrong floor choice.
If you're happy with 70% indoor humidity then it sounds like you're an amphibian who's happy to breath through your skin and that's coming from someone in the humidity capital of Jacksonville, FL.
I apologize if that sounded mean spirited but this thread sounds like a lot of needless stress.
Precisely. If it were that critical the 50-year-old hardwood floors in my MIL's house in Fargo ND would be a mess.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz