Insulation, Radiant and Vapor Barriers - Small cabin moisture problem
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Xolo
04-30-09, 05:31 AM
I need some help with this problem and am not sure where to post, so here it is.
I have recently built a small 8' x 12' cabin. From the inside out I used 6mil poly vapor barrier, Roxul R14 insulation, 2x4 wood frame construction, 1/2" plywood sheathing, Tyvek house wrap, vinyl siding.
The ceiling is also insulated with air allowance above to the shingles, but the floor is not yet insulated at all. The floor is built on 2x6 pressure treated wood, and 2 staggered layers of 3/4" tounge and groove plywood.
It is in a cold and moist climate (British Columbia, Canada).
There have been no cut-outs to allow for air exchange anywhere on the walls yet.
My problem is that I have noticed that there is a large amount of moisure build-up on the inside of the vapor barrier as well as the windows. Also, there can get a lot of moisture build up on the outside of the windows. This only happens if I do not run a small propane heater all day and night (but there is still moisure build up on the vapor barrier if there is something in front of it like a bag or box that keeps the heat from getting to it).
Now I only use the thing about 3-4 weeks a year, but I don't want to see it start rotting or have mold growing inside it. Plus there is no option to have a heater running 24/7/365.
Does anyone have any idea as to what the problem could be and how to fix/remedy it?
I have recently built a small 8' x 12' cabin. From the inside out I used 6mil poly vapor barrier, Roxul R14 insulation, 2x4 wood frame construction, 1/2" plywood sheathing, Tyvek house wrap, vinyl siding.
The ceiling is also insulated with air allowance above to the shingles, but the floor is not yet insulated at all. The floor is built on 2x6 pressure treated wood, and 2 staggered layers of 3/4" tounge and groove plywood.
It is in a cold and moist climate (British Columbia, Canada).
There have been no cut-outs to allow for air exchange anywhere on the walls yet.
My problem is that I have noticed that there is a large amount of moisure build-up on the inside of the vapor barrier as well as the windows. Also, there can get a lot of moisture build up on the outside of the windows. This only happens if I do not run a small propane heater all day and night (but there is still moisure build up on the vapor barrier if there is something in front of it like a bag or box that keeps the heat from getting to it).
Now I only use the thing about 3-4 weeks a year, but I don't want to see it start rotting or have mold growing inside it. Plus there is no option to have a heater running 24/7/365.
Does anyone have any idea as to what the problem could be and how to fix/remedy it?
airman.1994
04-30-09, 07:33 PM
Propane is a moist heat. When it is running you are adding RH to the air. I would allow for some fresh air to get in (open a window an inch or so this should remove the RH.