No. Insulation is not a source of condensation problems. Ventilation and vapor barriers are the general solutions.
Do I staple the flanges on faced fiber glass insulation to the face of the stud or to the inside
of the stud?
When stapling is necessary in cathedral ceiling projects, always staple insulation to the face of the rafter to
maintain the necessary 1" ventilation space. If Raft-R-Mate baffles have been installed up the entire length of the
cavity, then either way is acceptable. In other projects, such as walls, either way is also appropriate.
Does R-value refer to inches?
No. R-value refers to insulation's resistance to heat flow, not to its thickness. Tiny air pockets trapped in the
insulating material resist the passage of heat -- heat gain in the warm summer months, and heat loss in the
colder months. The higher the insulation's R-value, the greater its insulating power.
I know insulation helps keep heat in during the winter months, but is there any benefit to
having it during summer months?
Yes. Traditionally, insulation has been perceived as a cold climate product that is effective in helping reduce
winter heating bills. But the fact is, insulation can be just as effective in helping cut air-conditioning costs
during the hot summer months.
Regardless of outside or inside temperatures, the main concern is heat. Whenever there is a temperature
difference between outside and inside, there will be heat flow.
Insulation helps slow the transfer of summer heat entering the home, which helps keep the inside cool and
lessens the need for continuous air-conditioning. Similarly, in winter, insulation helps keep the house warm
by reducing the escape of interior heat.
I am in the middle of an insulation project, but I accidentally tore the vapor retarder. Is repair
necessary?
Not usually. The edges should lie close enough together to block most of the water vapor. To fix a large tear,
tape the two edges together with standard duct tape.
Does the vapor retarder on fiber glass insulation affect the R-value?
No. There is virtually no thermal performance difference between unfaced fiber glass insulation and kraft-faced
or foil-faced fiber glass insulation when properly installed. Faced insulation contains a built-in vapor retarder.
What happens when I compress fiber glass insulation?
Fiber glass insulation works on the principle of trapped air pockets. By compressing fiber glass insulation,
you decrease the amount of air trapped in the material, therefore reducing the overall R-value. So compressing a
thick product into a small space won't necessarily give you a better R-value. Typically if you take a thicker product and compress
it down to a smaller size you will end up with an R-value equal to one that is already available.
For example, compressing R-19 into a 2x4 wall cavity will give you an R-13. Owens Corning already make an R-13 batt,
so it is best to just purchase the R-13.
Compression Chart
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