Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

Basement walls insulation


kuhurdler's Avatar
Member

Join Date: Jul 2002
Posts: 588

10-13-04, 06:23 AM   #1  
Basement walls insulation

------------------


Last edited by kuhurdler; 02-18-07 at 12:08 PM.
 
Sponsored Links
resercon's Avatar
Member

Join Date: Nov 2001
Posts: 1,873
NJ

10-14-04, 03:19 PM   #2  
I would glue 1 inch fiberglass rigid board to the existing wall and 1/4 inch sheet rock over the rigid board.

 
kuhurdler's Avatar
Member

Join Date: Jul 2002
Posts: 588

10-15-04, 05:36 AM   #3  
----------------


Last edited by kuhurdler; 02-18-07 at 12:08 PM.
 
resercon's Avatar
Member

Join Date: Nov 2001
Posts: 1,873
NJ

10-15-04, 12:21 PM   #4  
No. The gap between the present sheet rock and masonry wall is a drainage plane. Besides having some thermal insulating qualities, it provides a buffer between the different materials. This is good because different materials absorb and expel moisture at different rates. The air in this dead space can easily absorb the moisture in heat as it traverses the wall in either direction.

This is very important with fiberglass insulation. That is because glass is not considered a solid, it is considered a fluid. Which means that it is at 100% Saturation all the time. In other words glass will not absorb any moisture in the heat and if it does it will be very little and will expel it almost immediately. If the fiberglass is in direct contact with the masonry, which absorbs moisture and expels it slowly, the probabilty that condensation will occur where the two meet is extremely high. Especially within the sub-grade part of the structure.

The dead air space provides the medium to absorb the moisture in the heat as it traverses the area. Which reduces the probability that condensation occurring dramatically, regardless of the different rates of absorption the different materials have.

 
kuhurdler's Avatar
Member

Join Date: Jul 2002
Posts: 588

10-17-04, 08:30 PM   #5  
-----------------


Last edited by kuhurdler; 02-18-07 at 12:08 PM.
 
resercon's Avatar
Member

Join Date: Nov 2001
Posts: 1,873
NJ

10-17-04, 10:23 PM   #6  
If you think about it, fiberglass insulation is used because of its characteristics, especially concerning moisture for basements, low absorbancy and fast expulsion rate. Ideally we would want all materials to have this characteristic. The problems arise when different applications interact with each other or in this case, when different types of materials that have different characteristics.

In the vast majority of basement applications you will find, the wall stud out with fiberglass insulation and sheet rock. If you were to examine this application, in the vast majority of each application, the majority of the fiberglass does not touch the masonry wall.

I take it a step further, I make sure the fiberglass does not touch the masonry wall at all by building the stud wall away from the masonry wall by at least an inch. I do it for the reason I mentioned in the other post concerning a dead air space and/or drainage plane.

 
Search this Thread