Posts: 2,980
Threads: 177
Joined: Aug 2006
Greetings. Sorry about the measles we sent you from San Diego. I specifically told them snakes. Snakes on a plane! Not measles! Anyway, my friends and tenants report that with the recent rain that the wood floors seemed a little "moist". The floors have polyurethane on top. I couldn't tell from the description whether the moisture was ON TOP or if it was perhaps coming from beneath. I am assuming the house was just to humid (near the water) that moisture just settled on the floor.
My house is on post and pier. (Love dat post and pier!). It occured to me -- are wood floors on post and pier usually sealed from below in some way? I have no idea what it looks like underneath. I assume the floor is put ON something. Any ideas?
Posts: 1,727
Threads: 29
Joined: Feb 2006
It all depends on how the house is built.
The way post and pier houses are built today, there is generally the concrete foundation blocks, metal Simpson ties to the 4" x 4" posts, up to solid sawn 4" by XX beams (assume metal ties between each piece of lumber) then 2" x XX floor joists then 3/4" thick T & G plywood sub floor. On top of that is the flooring of your choice.
The way the houses used to be built (early 70's up to the late 80's), it was a big concrete block, a small concrete block, a termite pan, posts, beams, floor joists and either T & G plank flooring or the 3/4" T & G subflooring.
Prior to that, it was flat rocks, posts, a beam, some joists (and they may have been 2"x 4" FLOOR JOISTS!!) and then 1" thick T & G flooring. That seems to have been common from about 1850 to about 1920. From 1920 to the 50's rocks for foundations were much less common.
That's just from what I've observed, so these numbers are not tight or possibly even valid. This is just from what I've seen on this island, Oahu and a few bits of Maui and Molokai.
"I like yard sales," he said. "All true survivalists like yard sales."
Kurt Wilson
Posts: 2,402
Threads: 145
Joined: Apr 2005
The one thing I have experienced at a vacation rental.
We arrived at 11:30pm to our rental, bottom of Beaches 3 houses from the ocean.
The two ceiling fans were on. To tired to take notice and turn them off, just fell into bed as it was by that time 3;30 am for us. The next day out and about, I turned the ceiling fans off. Well when we returned some 10 hours later, there was condensation everywhere! So we left the fans on for the rest of our visit and the condensation never reappeared. Hope this is a help. Oh also learned to put wet garbage in the freezer, before taking it out to the garbage, on that trip.
mella l
mella l
Art and Science
bytheSEA
Posts: 315
Threads: 28
Joined: Oct 2006
I think what they are experiencing is what we call a "dew-point" event. Both here in our house on a slab, and in Maui with a post and pier with wood floor, there are times when the dew point and outside/inside temps cooperate to have moisture condensing in the house. Yes, ceiling fans work to move the most air out and dry the floor. The first time it happened in Maui, it was amazing to realize we were nearly living in a fog bank in the house. Floors got damp, and all the windows fogged up. In Maui we were at about 600' in Haiku, and here on BI, we're at about 1050', mauka of Pahoa.
Jane
Posts: 589
Threads: 20
Joined: May 2006
Okay, this may be taking this thread off on a tangent, but we'll see. When we were looking for a new refrigerator, one of our wants was to get one with a stainless steel finish. One salesman (at Sears) cautioned us that in Volcano, where we live, stainless steel refrigerators will have condensation on the outside. We have never heard of this or seen it, but we accepted it and eventually wound up with one with a titanium finish. And, we've never seen condensation on it. But lack of evidence is not proof of the truth of that claim. I've been visiting a friend in Honolulu who lives on Tantalus, where it rains a lot and can be very windy. He tries to deal with the moisture by keeping windows open to allow for air flow. On rainy days, his stainless steel reefer has a large patch off condensation on the freezer door. On dry days, there's no condensation. Proof! This place is at about 1500 ft. elevation.
So, how does this have bearing on Glen's situation? I'm not sure, but maybe it's about how condensation happens: the water carried in warm moist air condenses when it comes into contact with a colder surface. Like the fogging on your windshield. And as Jane and Mella commented, fans moving air will help to keep this condensation from happening. I'm not sure if your subflooring has any significant role in this, except that it's the colder surface. It's probably a plus that you are up on posts and air can flow under the floors. I wonder if a small amount of subfloor insulation, as weird as it sounds, might help your situation by reducing the effect of low temperature under your floors? Thinking further on this, the number of days that low temps might cause condensation on your floors is what? Maybe it's something that happens for a few days every 2-4 years?
Posts: 179
Threads: 5
Joined: Aug 2006
Sounds like you've got it pegged, Les. The root cause of condensation is a temperature differential in a humid environment. The cure is removing the humidity or the temp. difference, and with HELCO rates being what they are, insulation would be most people's preferred choice.
Posts: 2,980
Threads: 177
Joined: Aug 2006
Man, I just turn you guys (and gals) loose and you come up with answers. There are (or soon will be!) some very talented people in Puna.
Okay, so if I understand, there are times when it may be cooler underneath the house (in the shade, and cooler air falls) than it is at floor level. Consequently, when it is very wet outside, condendation may form due to the temperature differential. And so, I might put insulation underneath to keep the temperature from getting too cool underneath and causing condensation. Do I have that right?
Posts: 2,402
Threads: 145
Joined: Apr 2005
Sounds good to me. I don't know if the insulation is needed for those few days every 2 to 4 years though like Les pointed out. Have to think on that for a while. In the mean time how about some good fans, portable on the floor leve or over head?
mella l
mella l
Art and Science
bytheSEA
Posts: 1,727
Threads: 29
Joined: Feb 2006
Depending on your situation, you may want to put screens in the floor to let the cool air into the house. That will level out the temperature difference, too. I've seen some old houses which had screened floors (a wooden grid for support and a screen to keep bugs out) in closets and then the closets had louvered doors. Those houses would be much cooler than their non-screened counterparts.
"I like yard sales," he said. "All true survivalists like yard sales."
Kurt Wilson
Posts: 2,980
Threads: 177
Joined: Aug 2006
All good suggestions...thanks again. I especially like the "retro" idea of putting screens in the floors. Could work in the closet really well. Probably the consensus, though, is that such condensation is pretty rare event. From what I understand, the crazy rains that have been coming down since December are unusual. This is a very wet winter from what I understand.
|
