Insulating Ceilings and Wall

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Posts: 8
Joined: Mon Jun 11, 2007 10:57 am
Location: Milton, WI

Sat Oct 08, 2016 10:30 pm

I have an older 14x70 that is used as a hunting and fishing cabin in northern Illinois. I currently do not have any leaks but decided to update the ceilings and wall panels in one of the bedrooms and while I was at it I removed the insulation. The walls had very thin unfaced insulation between the studs with no vaper barrier. The ceiling from bottom to top was ceiling panel, thin unfaced insulation between the wood trusses. wood trusses, vapor barrier, thin unfaced insulation and finally metal roof. I can't get insulation and vapor barrier between the trusses and metal roof so wondering the proper way to insulate the walls and ceilings. I read some posts here that indicated the insulation should not touch the metal roof or it will cause condensation which to me seems impossible and also that was how it came from the factory. Looking for any advice but specifically have the following questions:

Should I use unfaced insulation on both walls and ceilings like they did at the factory or should I use faced insulation? Do I use a vapor barrier regardless of whether I use faced or unfaced insulation?

Just a bit more information. The day I did the demolition it was warm and poured rain. The next day there was not a drop of water inside so I feel good there are no leaks. The next night was cool and I turned the furnace on. In the morning I checked the room and it was like a rain forest with all the condensation on the ceiling and walls. I assume once I get the insulation and vapor barrier in the condensation will go away, right?



Posts: 8
Joined: Mon Jun 11, 2007 10:57 am
Location: Milton, WI

Fri Oct 14, 2016 4:23 pm

Based on the recommendation at Menard's I used unfaced insulation in both the ceiling and walls and applied a vapor barrier on the ceiling only. Hope I don't need to start all over.

Posts: 80
Joined: Tue Oct 20, 2015 11:02 pm

Fri Oct 14, 2016 6:37 pm

Apply vapor barrier in all areas.
You want to stop vapor/moisture from migrating to cold surface.
Example: glass of ice water that has moisture collect on glass.
Cover walls and ceiling with clear plastic, overlap seams min on 6 inches.
Gasket/seal all elec boxes and at wires entering j boxes Any holes in top or bottom plates should be caulked.
Caulk bottom plates at intersection of floor decking.
Make sure room has a path for return air back to furnace.
Could be grill in wall or door under cut.

Posts: 22
Joined: Mon Oct 17, 2016 4:38 pm

Tue Oct 25, 2016 10:16 pm

Faced fiberglass batts are meant to serve as a moisture barrier so you did the right thing. You only want one barrier or moisture will collect in between. The attic area in any home condensates heavily. This is the reason for roof and eave/soffit venting otherwise there would be mold. The walls may vent moisture inside the home. That may be the purpose of having no barrier. Mobile homes (especially older ones) are a bit confusing when it comes to venting. You can always use furring strips underneath the joists if you need additional space to insulate.