Hello,
I looked at a house under construction today with what apears to be a serious moisture problem. It is a timber frame building, studed between the posts with 2″ x 4″s, sheathed with OSB and wrapped with Tyvek. The first floor of this building is a garage with uninsulated concrete slab floor. The walls are insulated with fiberglass, paper faced batts. A wood stove was installed recently. With the stove operating the inside of the sheathing and the back of the fiberglass throughout the building has become wet. There is so much moisture it is dripping down the sheathing and out along the face of the foundation. My questions are: Where might this moisture be coming from? The OSB did get wet during construction, might this moisture just be from that and if so will it eventually dry up? What options are there for drying this building out? I would appreciate any thoughts on this issue. Thanks
Replies
More info, if you would.
How long since the concrete was poured?
What is your geographical location, elevation, etc.?
Thanks for your response. A little more info about this wet house. The concrete was poured in June with a plastic vapor barrier under. It is located in southern Vermont where the weater has been very variable for the past couple of months. The moisture was not detected by the plumber or electrician. Only after the insulation was installed and the wood stove fired up did the water start dripping. The biggest concern is will the OSB dry out and what affect does moisture have on the stuff . Thanks
The sources of potential moisture have already been covered pretty well IMO.
If I'm reading this right, those FG batts are just stapled up in the wall. The now wood stove heated, moisture laden air is making it's way thru the resulting cracks and condensing on both the FG and the OSB sheathing. In order to get things dried out eventually, a fella might well have to remove the FG, get it dried out, remove the paper from the FG or replace with new unfaced batts and immediately install a well-sealed plastic vapor barrier. Then get the drywall or alternate in place pronto.
Knowledge is power, but only if applied in a timely fashion.
Another possible source of moisture can occur during construction. If people were running unvented propane heaters in the building envelope in freezing weather, they can deposit hundreds of pounds of water unto to FG as it freezes.
Don't know if it's been mostly below feezing for you, but up here, some houses have been ruined by the water damage once hundreds of gallons of frozen FG thawed and soaked the sheetrock and everything else.
They don't die of CO poisoning because there's enough air flow through the unfinished building. But while the air flows out, the water vapor only gets as far as the freezing point in the insulation.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Ya know......if it's really that wet inside this building and drying it out is of the essence, then perhaps a guy should consider resorting to venting it as one would a moisture laden bathroom or kitchen.
You'll burn some extra wood to be sure, but if potential damage to the OSB is a concern, it may well be worth it.
Knowledge is power, but only if applied in a timely fashion.
A lot of water is incorporated in construction materials (concrete, wood, drywall, paint) and the materials soak up more if there is rain or snow. It will dry out very slowly once the weather turns cold and will not seem to be wet at all. When you turn on the heat, moisture condenses on any cold surface. If the house is finished, this will often be the windows. It is common in our houses for water to collect on the bottom of the window sashes during the first winter, sometimes in alarming amounts. We have the homeowners wipe this up as much as they can and also leave a few of the windows cracked open. The problem will slowly resolve itself over the first heating season.
Your building is at an earlier stage and should dry out even faster.
It can be coming from the air.
It can be working out of the concrete.
It could be that all the materials had some moisture on them.
Everybody stopping it to look around is probably stomping the snow off their feet when they go in.
The posts and beams might be green.
The wood stove is a pretty good option for starting the drying process.
Excellence is its own reward!
Has the start of using the woodstove co-incided with a change in the weather? Such as a drop in temperature, making it more likely moisture will condense on cold surfaces?
Is the woodstove vented properly - combustion gases contain a lot of water vapor, although with a wood stove you'd expect to smell the smoke if it isn't vented properly.
Probably water vapor from the concrete work, is my guess.
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Most timberframe buildings are built with wood in the 25% moisture area and above..
(sometimes as high as 50% depending on species of wood.)
even kiln dried 2x4's will have about 19% moisture.
Pick up a timber, note hiow heavy it is? up to half of that weight is water that has to be dried out..
the first few times you fire up some heat you are trying to get rid of a lot of water.
probably tons of it,
it really shouldn't matter because hopefully it's far from fully sealed up and the water has to go someplace..
Now a note, the faster you dry out those timbers the more stress they will go through and the more they will twist and warp.. (and check) if the appearance of the building is a consideration, dry it as slowly as possible with as low a temp as is comfortable..
well ray since it under construction today, and i'm hoping you are north bound there are lots of reasons for moisture. was there 3mil poly laid on the ground before the slab was poured? is there 3mil poly on the walls before the sheetrock was screwed? is there a Heat Recovery Ventilator installed befoer the wood stove was installed? lots of questions, not enough info.
I built a timberframe this summer as well, in northeastern VT, and also had moisture problems. It rained throughout the week that we had the frame enclosed with SIP's (August) and consistently for several weeks afterward. During that time, the sheetrock was thoroughly saturated around the window openings, and the timberframe became stained with mold. We did not get the windows in until October. I have decreased the amount of moisture inside the envelope considerably (as judged by the amount of frost on the inside of the windows), but the entire frame will have to be sprayed with bleach water and then sanded to remove the mold. I'll probably wait until next summer, when I can be sure the mold will not return. My timberframer assures me that he has never seen a frame mold up like this before. If I were you, I would keep a close eye on your frame for signs of mold, especially in the spring....
Mike Fitz
Hello Mike, Thanks for the reply in regards to my moisture problem. The heat has been on with fans blowing and windows open just a crack and the place seems to be drying up. Whew! Fortunately little of the exposed frame will need the bleach treatment but some insulation removed and walls wiped down. Thanks again, I appreciate your note.