I have an attic in my wooden house from the 1930s where the attic floor is insulated with about 13cm of peat moss and 8cm of fiberglass mats on top. Under the peat moss, there is a tar paper on the roof sheathing.
I need to improve the insulation, which is uneven and insufficient. I plan to remove the fiberglass mats and blow cellulose fiber insulation, like eco fiber. What I'm considering is whether I should improve the vapor barrier to prevent warm and moist air from rising into the attic.
Question 1: Should I then remove the peat moss as well and lay new plastic or vapor-permeable fabric and then blow new cellulose fiber, or is it enough to just remove the fiberglass and blow new cellulose fiber?
Question 2: I am going to build a new bathroom underneath, and the floor there will be exposed to more moisture. Is it sufficient if I lower a ceiling and paint with bathroom paint, or should I do something more?
I need to improve the insulation, which is uneven and insufficient. I plan to remove the fiberglass mats and blow cellulose fiber insulation, like eco fiber. What I'm considering is whether I should improve the vapor barrier to prevent warm and moist air from rising into the attic.
Question 1: Should I then remove the peat moss as well and lay new plastic or vapor-permeable fabric and then blow new cellulose fiber, or is it enough to just remove the fiberglass and blow new cellulose fiber?
Question 2: I am going to build a new bathroom underneath, and the floor there will be exposed to more moisture. Is it sufficient if I lower a ceiling and paint with bathroom paint, or should I do something more?
13 cm peat moss corresponds to about 5 cm mineral wool in terms of insulation. It is an organic material. It is slightly better than solid wood and slightly worse than sawdust as an insulating material. The volume weight is 0.2, which corresponds to heavier types of mineral wool. Since you are going to use another organic material, cellulose fibers, I think you can remove the peat moss.
Manufacturers of cellulose fibers usually recommend using a special vapor barrier cloth instead of plastic film. The problem with the bathroom on the underlying floor I find difficult to assess in this case. Even though it gets very humid in a bathroom, it is not certain that all the moisture binds as water vapor in the air and can move upwards. That mainly depends on the air temperature. I would probably consult the manufacturer of the cellulose fibers.
Manufacturers of cellulose fibers usually recommend using a special vapor barrier cloth instead of plastic film. The problem with the bathroom on the underlying floor I find difficult to assess in this case. Even though it gets very humid in a bathroom, it is not certain that all the moisture binds as water vapor in the air and can move upwards. That mainly depends on the air temperature. I would probably consult the manufacturer of the cellulose fibers.
Thanks for the response. I'm not quite following the reasoning behind removing the peat moss. The downside of removing it is that it's a lot of work. If I need to add a new vapor barrier under the new insulation, then it's unavoidable; otherwise, the only downside is that peat has a worse U-value than the new insulation, right?
Regarding the bathroom, I should probably check with the supplier as you suggest.
Best regards, Carl
Regarding the bathroom, I should probably check with the supplier as you suggest.
Best regards, Carl
It's possible to remove the torv without the house getting a shock when you replace it with cellulose fibers. You don't have to remove the torv. The only motive is to improve the U-value.
Yes, then I understand what you mean, thank you.