Serious moisture problem inside wall cavities
Hi, I am looking for a solution or cause for a problem a local(Columbia Gorge area, Oregon) contractor called me about today:
He said the house he is almost completed(dry-walled/painted, doing finish work on it now) has a serious problem the plumber discovered:
The guy was about to install cement board over the insulation so he can start tiling the new shower stall, he moved some of the insulation, discovered the back-side(against the exterior sheathing( note: exterior sheathing installed is called ZIP PANELS, which does not require house wrap!) was extremely wet!
Contractor started checking other exterior walls, finding the same problem. I asked him a few questions, like: What was the moisture content of the framing? Answered 12%; What about a vapor barrier? he said the dry waller applied it with the primer-sealer. What is the attic space like(referring to moisture)? He said it noticed it was dry, with exception to an area w-o venting, where the cavity did show signs of moisture.
House was framed during the winter. Shell was covered before the bad/cold weather hit.
Okay everyone, tell us whats wrong!!!!!! PLEASE! Contractor said he thinks he is going to have to strip the walls!
Thanks MUCH!
Replies
How did they heat the place during construction? I'm guessing they used propane or kerosene torpedo heaters. They produce an enormous amount of water from the combustion.
Thanks! I asked the contr. about that. Not sure what he said. But you're right, those propane heaters dump ALOT of moisture! Th heating system for the house is an electric furnace/heatpump.
I will check into this issue further. If indeed they used propane heater, any suggestion for the moisture ? Also, should the vapor berrier have not prevented that moisture from entering the cavity?
The vapor barrier (where it was in place) should have slowed things, and once the source of moisture is removed (and the house allowed to air a bit in warmer weather) the water should dissipate.
Place a hygrometer in the structure and make sure the humidity stays below 30% or so (with windows closed) in cooler weather.
Re-reading your original post I don't see any mention of a vapor barrier on the inside. Without such a vapor barrier humidity will go through the wallboard and insulation and settle on the Zip panels (which function as a vapor barrier of sorts). This may be the root of your problem, if it's not explained by the heating method.
vapor berrier
Hi, the contr was told by the dry-waller he applied a spray-on berrier with his primer/dealer paint. I still believe this is the probable cause. May be the min. perm was not applied? Thanks for the input. I will let him know what you suggest about the humidity & letting things dry out.
Typical
You need to run some heat (NOT a propane salamander or anything else that adds water to the air) and you need to run dehumidifiers, the large type used by dryout companies. Go to your rental place and get 1-2 4000-watt electric heaters and have the electrician wire them up. Put in 1-2 dehumidifiers like Drizair 110 or similar, and run them for a couple of weeks. You will be surprised at how much water you will collect.
If the contractor stripped the walls (whatever that means)... what would he do next?? That won't solve anything. You need to (and can) EXTRACT the moisture.
IMO you also need a good, accurate thermometer/hygrometer so you can monitor interior humidity at 1-2 spots in the house.
Continue heating and dehumidifying until the moisture level is low enough (let's say target 35% at 68 degrees) and stays there. I typically run it through the painting stage if not longer.
Thanks much for your wisdom & help. I will pass this info on to the contr!