Insulation, Radiant and Vapor Barriers - Running out of time! Insulating an enclosed crawl space/eve. Help quick, please!
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StevenG
12-10-07, 08:23 PM
Hi All,
We are in the process of finishing off a partially finished bonus room over our 3 car garage. The side walls are angled with the exterior roof and have storage/crawl spaces on both sides. They are insulated on all 4 sides, and under the insulation on the roof section, are the plastic air channels to let air circulate up to the attic space above the room. I assumes of this air stays in this crawl space as well as those channels are far from air tight. As I mentioned, the previous owner put fiberglass insulation over these air channels, covering them in these spaces. Is this right?
The problem is this too - two of these three areas are being sealed off in the next day or two by a carpenter since the baseboard hot water heat will go against these walls, rendering the access unavailable via doors, so I have to act quick if it needs to be changed. Keep in mind that the space inside the room, even with these cavities will be heated. Above the room is cold attic.
So should the roof line be insulated as well, covering the ducts, or should that crawl space be able to get cold like the attic above would? Should I pull the insulation from the roof sections completely, or just perhaps every 3rd section? Or is it ok since the space next to it (inside) will be heated? I'm not sure what to do.
Here's a couple of pics showing the area from the outside, and then an inside shot and a shot of the insulation pulled down so you can see the air channel.
I'd like to think the whole area can stay insulated to help with heating and stuff, but I don't want condensation problems down the road since I can't get in there easily.
One more thing too, the bottom of the roof line terminates below the floor you can see at the soffit vents over the garage doors, about 10' off the ground.
Thank you so much for helping...
http://www.sixsyllables.com/miscpics/atticroom.jpg
http://www.sixsyllables.com/miscpics/atticspace.jpg
http://www.sixsyllables.com/miscpics/atticduct.jpg
We are in the process of finishing off a partially finished bonus room over our 3 car garage. The side walls are angled with the exterior roof and have storage/crawl spaces on both sides. They are insulated on all 4 sides, and under the insulation on the roof section, are the plastic air channels to let air circulate up to the attic space above the room. I assumes of this air stays in this crawl space as well as those channels are far from air tight. As I mentioned, the previous owner put fiberglass insulation over these air channels, covering them in these spaces. Is this right?
The problem is this too - two of these three areas are being sealed off in the next day or two by a carpenter since the baseboard hot water heat will go against these walls, rendering the access unavailable via doors, so I have to act quick if it needs to be changed. Keep in mind that the space inside the room, even with these cavities will be heated. Above the room is cold attic.
So should the roof line be insulated as well, covering the ducts, or should that crawl space be able to get cold like the attic above would? Should I pull the insulation from the roof sections completely, or just perhaps every 3rd section? Or is it ok since the space next to it (inside) will be heated? I'm not sure what to do.
Here's a couple of pics showing the area from the outside, and then an inside shot and a shot of the insulation pulled down so you can see the air channel.
I'd like to think the whole area can stay insulated to help with heating and stuff, but I don't want condensation problems down the road since I can't get in there easily.
One more thing too, the bottom of the roof line terminates below the floor you can see at the soffit vents over the garage doors, about 10' off the ground.
Thank you so much for helping...
http://www.sixsyllables.com/miscpics/atticroom.jpg
http://www.sixsyllables.com/miscpics/atticspace.jpg
http://www.sixsyllables.com/miscpics/atticduct.jpg
d00bs
12-10-07, 10:56 PM
Read over these pdf files and follow the steps they outline as close as you can.
http://www.dom.com/customer/efficiency/res/pdf/rooms_over_garages.pdf
Also read the 4th page of this file http://www.eere.energy.gov/buildings/info/documents/pdfs/26447.pdf
In short you are going to have 2 types of "side attics" sealed and one for storage. The sealed or closed up one needs to have insulation only against the back of the kneewall and the floor too if its over living space. Make double sure you caulk and/or use spray foam to seal the floor/kneewall junction cause air can get thru fiberglass. If you have time cover the back of the insulation on the kneewall with sheets of foamboard or even tyvek housewrap (allows moisture thru but not air) with all seams taped and sealed for both. This also prevents windwashing of the fiberglass so it can work correctly and keep its R value.
For the storage side attic you need to make a real air barrier down along the roof rafters (fiberglass on the kneewall isnt necessary here since it will be open to the lving space) also check the floor here to see what its over. It takes some time to do this though. Again use blue or pink foamboard or even plywood to sheath the rafters (use nails with washers) enclosing the insulation. Caulk foam and or tape all seams. Also use sprayfoam to seal the rafter/kneewall joint here. Follow the instructions in those files on where exactly to caulk ot foam and even to put the insulation. Since you are short for time work on the ones to be sealed up first then tackle the storage areas. One last note. The storage areas should be inside your thermal (insulation) envelope and not super cold like the upper attic. If you do it right it will be colder than the room but warmer than the upper attic space. The sealed side attics are supposed to be outside the envelope and cold thats why you only insulate and cover the back of the kneewall and the floor if necessary.
Good luck
http://www.dom.com/customer/efficiency/res/pdf/rooms_over_garages.pdf
Also read the 4th page of this file http://www.eere.energy.gov/buildings/info/documents/pdfs/26447.pdf
In short you are going to have 2 types of "side attics" sealed and one for storage. The sealed or closed up one needs to have insulation only against the back of the kneewall and the floor too if its over living space. Make double sure you caulk and/or use spray foam to seal the floor/kneewall junction cause air can get thru fiberglass. If you have time cover the back of the insulation on the kneewall with sheets of foamboard or even tyvek housewrap (allows moisture thru but not air) with all seams taped and sealed for both. This also prevents windwashing of the fiberglass so it can work correctly and keep its R value.
For the storage side attic you need to make a real air barrier down along the roof rafters (fiberglass on the kneewall isnt necessary here since it will be open to the lving space) also check the floor here to see what its over. It takes some time to do this though. Again use blue or pink foamboard or even plywood to sheath the rafters (use nails with washers) enclosing the insulation. Caulk foam and or tape all seams. Also use sprayfoam to seal the rafter/kneewall joint here. Follow the instructions in those files on where exactly to caulk ot foam and even to put the insulation. Since you are short for time work on the ones to be sealed up first then tackle the storage areas. One last note. The storage areas should be inside your thermal (insulation) envelope and not super cold like the upper attic. If you do it right it will be colder than the room but warmer than the upper attic space. The sealed side attics are supposed to be outside the envelope and cold thats why you only insulate and cover the back of the kneewall and the floor if necessary.
Good luck