Framing/Insulating in Corners
#1
08-17-05, 10:39 AM
Framing/Insulating in Corners
We are getting ready to frame, insulate, and drywall a storage room in the basement. We are using 2x4 lumber with R-13 batting. I plan on framing about 1 – 1 ½” in from the cement block walls. I’ve seen tons of information on this and it all seems pretty straight forward. However, I have an unusual situation that I wanted to run by folks.
All 4 walls of this storage area are cement block. However, one wall is actually an interior wall of the house. As a matter of fact, the furnace is on the other side of the wall from the storage area. All the information I have seen addresses this framing technique as something going around the outside walls of the entire basement.
In my situation, if all my framing and insulation is set off all the walls, the gap would run all the way around the room, 3 exterior and 1 interior wall. Warm air from the interior wall would flow along that gap, hitting cold air on the exterior walls. It would seem to me that would just create a condensation problem behind my framed walls. It would also seem to me that I need to make sure the entire length of the exterior wall is insulated, rather than having a gap all the way around the room. In other words, the 3 exterior walls as an enclosed insulated area, separate from the 1 interior wall.
I am curious about the best way to frame and insulate the corners where the exterior and interior walls meet. One option: at that corner, my exterior wall framing would run all the way to the cement block on the interior wall. I would have a pressure treated stud at the end and could then insulate the entire exterior wall up to the stud on the interior wall. Is there a better way?
Thanks in advance.
P.S. I am also curious about insulating at the exterior door and window. The framed wall will be set away from the exterior foundation wall, so, how do I best insulate the 1 – 1 ½” gap around the window and door.
Thanks again, and hope I explained all this well enough.
All 4 walls of this storage area are cement block. However, one wall is actually an interior wall of the house. As a matter of fact, the furnace is on the other side of the wall from the storage area. All the information I have seen addresses this framing technique as something going around the outside walls of the entire basement.
In my situation, if all my framing and insulation is set off all the walls, the gap would run all the way around the room, 3 exterior and 1 interior wall. Warm air from the interior wall would flow along that gap, hitting cold air on the exterior walls. It would seem to me that would just create a condensation problem behind my framed walls. It would also seem to me that I need to make sure the entire length of the exterior wall is insulated, rather than having a gap all the way around the room. In other words, the 3 exterior walls as an enclosed insulated area, separate from the 1 interior wall.
I am curious about the best way to frame and insulate the corners where the exterior and interior walls meet. One option: at that corner, my exterior wall framing would run all the way to the cement block on the interior wall. I would have a pressure treated stud at the end and could then insulate the entire exterior wall up to the stud on the interior wall. Is there a better way?
Thanks in advance.
P.S. I am also curious about insulating at the exterior door and window. The framed wall will be set away from the exterior foundation wall, so, how do I best insulate the 1 – 1 ½” gap around the window and door.
Thanks again, and hope I explained all this well enough.
#2
08-22-05, 03:16 PM
I don't quite understand why the one interior wall is concrete block. Also, is the storage area going to be heated? Is the furnace room heated? I would probably just treat it as if it were an exterior wall and frame it and add insulation anyway. If you use your approach of running the pressure treated 2x at the end, you still won't close the gap because the walls are never even. Your approach sounds like it would work though. You could even caulk the gap between the PT stud and the cement wall I would think.
With regards to framing around the door and window, just frame around them and insulate normally, leaving a gap around the inside edge of the the window casing. Later you can finish them by wrapping the opening with wood or drywall. You would caulk the gap between the wood or drywall and the window frame.
I guess the big question I have is why you are bothering to frame it out at all if it is just a storage room. Are you converting it to a habitable space? If so, you should make sure you follow code. You local building inspectors office can probably offer a lot of advice too.
With regards to framing around the door and window, just frame around them and insulate normally, leaving a gap around the inside edge of the the window casing. Later you can finish them by wrapping the opening with wood or drywall. You would caulk the gap between the wood or drywall and the window frame.
I guess the big question I have is why you are bothering to frame it out at all if it is just a storage room. Are you converting it to a habitable space? If so, you should make sure you follow code. You local building inspectors office can probably offer a lot of advice too.
#3
08-23-05, 04:13 AM
Framing/Insulating in Corners
Thanks for the advice. I was also thinking I might could use something like Great Stuff foam insulation to spray in the gap between the wood and the wall.
Yes the storage room is going to be heated. The other part of the basement with the furnace area and rec room are already conditioned space. Ultimately, the storage will probably be my shop as well. While that still doesn't mean we needed to frame it all out, I was already framing the 3 exterior walls so I can insulate... I figured what's one more. And its a good wall for some long shelves, too.
I appreciate it.
Yes the storage room is going to be heated. The other part of the basement with the furnace area and rec room are already conditioned space. Ultimately, the storage will probably be my shop as well. While that still doesn't mean we needed to frame it all out, I was already framing the 3 exterior walls so I can insulate... I figured what's one more. And its a good wall for some long shelves, too.
I appreciate it.
#4
08-23-05, 07:27 PM
IN additoin to the other options mentioned, have you looked at the possibility of using a rigid, foam or polystyreen insulation that you adhere directly to the concrete walls? If you use PT studs, you could also place those against the walls, with the rigid insulation between them. Or, put up the insulation, and run the stud walls against them. Even if you did this only on the interior wall, that should address any issues with the condensation.
#5
08-24-05, 10:33 AM
Using the rigid insulation would help with the questions I had once I started planning out the details. I think one of the main reasons I decided on the batting earlier was because most of that area of the basement is actually above grade.
There is only one wall that is completely below grade. The grade on a second wall drops fairly steeply from the top of the room to the floor of the room. That wall is below grade then drops to above grade in a span of about 10 feet on a 28 foot wall. The last exterior wall is all above grade. Since most of the walls were above grade, they are subject to more extreme temperatures. I thought the additional R value of the R-13 batting would be better.
I thought the batting was also more cost effective. However, I didn't research that end as much. Is the rigid insulation that much more than the batting?
Again to all for the advice.
There is only one wall that is completely below grade. The grade on a second wall drops fairly steeply from the top of the room to the floor of the room. That wall is below grade then drops to above grade in a span of about 10 feet on a 28 foot wall. The last exterior wall is all above grade. Since most of the walls were above grade, they are subject to more extreme temperatures. I thought the additional R value of the R-13 batting would be better.
I thought the batting was also more cost effective. However, I didn't research that end as much. Is the rigid insulation that much more than the batting?
Again to all for the advice.
#6
08-24-05, 11:04 AM
Member
Basement insulation
Over-insulation in a basement is far too easy to do and can be a waste of money in terms of construction cost and operating cost.
When you insulate, you are concerned with the temperature differential between to spaces. In a basement, the need for insulation is far less than the remoander of a home. In Minnesota, where I am, the soil temperature at depth is about 54 degrees or much warmer than the outside air temperature. Since the temperature differential is less the amount of insulation you can justify to use is less.
In the summer, the insulation in a basement will cost you money operating your AC. This is because you are not taking advantage of the temperature moderation provided by the soil and foundation. Because of the mass of the foundation, there is no magic line at grade the grade line. Everywhere in the country, in the winter, soil will be warmer than the air.
The key to economical basement comfort is not a lot of insulation, but intellegent control of humidity and moisture.
Rigid foam (extruded polystyrene) has more insulating value than fiberglass and does not lose insulating value (as much as 50%) when subjected to high humidity and moisture.
I have been involved in codes and applications for many years. During this time I have seen two or three complete reversals in thinking. I have learned the goldern rule - "When you follow a code, you are not wrong, but you may not be right". This means use common sense whenever possible and over-insulating, over-analyzing and missing the big picture on a home (including surrounding soil) can easily be an example.
Dick
When you insulate, you are concerned with the temperature differential between to spaces. In a basement, the need for insulation is far less than the remoander of a home. In Minnesota, where I am, the soil temperature at depth is about 54 degrees or much warmer than the outside air temperature. Since the temperature differential is less the amount of insulation you can justify to use is less.
In the summer, the insulation in a basement will cost you money operating your AC. This is because you are not taking advantage of the temperature moderation provided by the soil and foundation. Because of the mass of the foundation, there is no magic line at grade the grade line. Everywhere in the country, in the winter, soil will be warmer than the air.
The key to economical basement comfort is not a lot of insulation, but intellegent control of humidity and moisture.
Rigid foam (extruded polystyrene) has more insulating value than fiberglass and does not lose insulating value (as much as 50%) when subjected to high humidity and moisture.
I have been involved in codes and applications for many years. During this time I have seen two or three complete reversals in thinking. I have learned the goldern rule - "When you follow a code, you are not wrong, but you may not be right". This means use common sense whenever possible and over-insulating, over-analyzing and missing the big picture on a home (including surrounding soil) can easily be an example.
Dick
