Moisture

[brokenthumb]

I have a home that was built in 1974. I removed the old cladboards, and found the house sheathed in dynaconda, or tentest, or whatever you want to call it . On the east facing gable end of the house, I removed the tentest, and replaced it with plywood. A carpenter told me not to bother pealing the rest of the house, and to just put the plywood over the existing material. So old siding removed, plywood over tentest, on 3 sides, new windows, doors, fanfold insulation, and new vinyl siding. I then gutted the 2 rooms on the east end of the house. Rewired, reinsulated, vapor barrier, and re gyprocked them. I live in Canada, so we get a wide range of weather conditions. I noticed dirty water dripping out of the siding, Never thought much of it as we had a wood stove, and the attic is a bit sooty. The rest of the house needs re insulating, and I assumed heat loss in the attic was causing the moisture. Today however, I was outside with my daughter, and noticed that I could see the imprint of the studs through the siding. We had a really cold spell, and then it turned mild. What could be causing this. The other 3 walls are fine.

 

[nealtw]

Welcome to the site. !974,,, 2x4 exterior walls ? limited insulation? Studs are a heat loss, I suspect that the donicona is spreading the heat lose over a larger area.

 

[brokenthumb]

We have been having pretty massive temperature swings this winter. Yesterday was -27C, and today was -3, and tonight is -20 again. The insulation was just thrown in place before, lots of air gaps, and no inside plastic. Took great care with the insulating. No gaps, not too tight, and wire running in the middle of the batts, not behind, or in front. I should have went with 2 inch insulation instead of fanfold.

 

[nealtw]

I haven't used fanfold, not a believer. You do have to be carefull of mixing technoligies. One is to insulate the walls on the inside with a vapour barrier to keep moist air in the house, while allowing the house to bearth with holes and cracks in the exterior sheeting that is wraped with house wraps which stops water but breaths. The other is to have insulation on the outside and seal that up so it protects the house from water and moist air and no vapour barrier on the inside. I think the idea is that over the life of the house wll will get wet for one reason or another and it needs a way to dry out.

 

[GBR]

Welcome!

The "ghosting" is caused by the warm studs against the cold outdoors, it also works the other way (cold studs against warm indoors to collect dirt) - fig. 11; https://www.google.com/search?q=six+ways+for+condensation+in+buildings&ie=utf-8&oe=utf-8

Once you install the interior gyp-rock (drywall), the problem should stop. Be sure to ADA it; http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

2" foam board would have been far superior to the fanfold (used to level out irregularities- not insulate) and eliminated the need for a vapor barrier interior- as Neal said. http://www.buildingscience.com/documents/insights/bsi-049-confusion-about-diffusion
Though someone needs to update/correct their info terms, lol;http://www.greenbuildingadvisor.com...need-breathe-and-9-other-green-building-myths

Gary

 

[brokenthumb]

Thanks... As I said, this is the only wall that is doing this. The other 3 walls have drywall, vapour barrier, fiberglass pink, tentest, or dynaconda, or a black tarboard..everyone has a different name for it. Then plywood, fanfold. then siding. The problem wall is only missing the tentest. The house is very energy inefficient. We never really noticed when we were burning wood, but I got rid of the wood stove. The first winter without wood was uncomfortable, so I began the renos, and still have lots of inside work to do. The rooms next to the problem wall are finished, and are warm, so that is why the outside moisture surprised me.

 

[Big Red]

Well, you also have to understand that a house needs to breathe. Many people don't consider how much moisture is contained in a house with a number of people living in it. Cooking, bathing,even breathing causes a lot of moisture that needs to go somewhere. I'm still not sold on the interior vapor barrier thing. You don't want to keep the moisture in---you want to get rid of it. If a house is so tightly built--as some houses in Canada can be--I'm more in favor of a mechanical heat exchanger to get rid of moisture while retaining maximum heat.