Insulation..when is too much too much?

[ekartal5]

Gerry,

Does this all depend on the climate of the region? I've only inspected in Illinois where paper side up on an attic floor would turn the insulation into a sponge.

Erol Kartal

[tneumann]

*Sigh.....I guess I know what I'm doing when the HVAC guy calls me for the appt.....I thiought I was just going to be learning something about a furnace...now I can see I'll be climbing and getting more itchier....better get out the "carharts"...

[gbeaumont]

Originally Posted by ekartal5

Gerry,

Does this all depend on the climate of the region? I've only inspected in Illinois where paper side up on an attic floor would turn the insulation into a sponge.

Erol Kartal

Erol, yes the local climate is the key, the vapor barrier should be against the warmer and moister (sp) air, for example here in florida where we have warm damp outside air, and cool drier (if the AC is working) inside air the vapor barrier would be the oposite of where you live.

From the link that Todd posted:

Why does the climate change the way you should use insulation? Remember that diffusion usually carries moisture from a warmer space to a colder space, and that moisture will condense to a liquid, or even solid, form if it contacts a cold surface. The location of the cold surface, and the location of the higher moisture concentration both vary with climate and season. If the outside air is colder than the inside of a home, then moisture from inside the warm house will try to diffuse through the walls and ceiling toward the cold, dry outside air. If the outside air is hot and humid, then moisture from outside will try to diffuse through the walls toward the dry, air-conditioned inside air. In both of these cases, what’s important is the difference between the inside and outside climates. So next-door neighbors could install the same insulation and vapor retarder but get very different results, depending on what temperatures they maintain inside their homes and how much moisture their lifestyles generate.

having said that with the relatively low RH in the air in AZ the inside of the property may actually be the moister (sp) or have the higher RH.

Confused yet ................... you should be

Regards

Gerry

[Ted Allen]

Also from the link:

Blanket Insulation: Batts and Rolls
Installing batts and rolls in attics is fairly easy, but doing it right is very important. On unfinished attic floors, work from the perimeter toward the attic door. In new construction, the vapor retarder facing should be installed with the facing placed down toward the ceiling gypsum board, except in hot humid climates where unfaced batts should be used. If reinsulating over existing insulation, it is recommended that unfaced batts be used. If there is not any insulation in your attic, fit the insulation between the joists. If the existing insulation is near or above the top of the joists, it is a good idea to place the new batts perpendicular to the old ones because that will help to cover the tops of the joists themselves and reduce heat loss or gain through the frame. Also, be sure to insulate the trap or access door. Although the area of the door is small, an uninsulated attic door will reduce energy savings substantially.

[tneumann]

That sounds way too much like a judgement call to me.....doesn't sound too definitive....*sigh*

[Brian E. Kelly]

Originally Posted by tallen

Also from the link:

Blanket Insulation: Batts and Rolls
Installing batts and rolls in attics is fairly easy, but doing it right is very important. On unfinished attic floors, work from the perimeter toward the attic door. In new construction, the vapor retarder facing should be installed with the facing placed down toward the ceiling gypsum board, except in hot humid climates where unfaced batts should be used. If reinsulating over existing insulation, it is recommended that unfaced batts be used. If there is not any insulation in your attic, fit the insulation between the joists. If the existing insulation is near or above the top of the joists, it is a good idea to place the new batts perpendicular to the old ones because that will help to cover the tops of the joists themselves and reduce heat loss or gain through the frame. Also, be sure to insulate the trap or access door. Although the area of the door is small, an uninsulated attic door will reduce energy savings substantially.

Vapor barrier faces the conditioned space. I understand diffusion, but what is humidity?

Don't see batts so much any more, too labor intensive. Many of the newer homes have blown in fibre glass about 15 inches. I find I itch less inspecting attics wearing shorts. I'll see if I have a picture.