Attic insulation

[Guest guest]

I don't think I get a lot of uneducated opinions but I do read from a variety of

sources but don't act on them until I check them out from a reliable source.

Before I had a house problem, I had work done on my house that caused a lot of

problems from companies that were referred by word of mouth...neighbors that

were happy with their work. However I have found that many people who are in a

particular business really are not the experts that I people might think they

are.

Plans to insulate my attic are from an energy audit company through my gas

company. The plans are for cellulose but I just read on the 'internet' someone

said that they have a lot of experience with insulation..didn't say what

kind...and that cellulose was a fire hazzard, so I came here to ask the

question. Thanks

>

> Barb

> Cellulose insulation includes a fire retardant (often Borax and boracic acid)

that makes it quite hard to burn. Over time it may lose some of its fire

retardant capabilities near the upper surface, as the powder settles due to

vibration, but it should not be a problem. A fire starting on top of the

insulation would not work down to the house very quickly, especially if the

attic were well air sealed. If the fire starts up into the attic from the house,

you are already toast, so that should not be a consideration in what you choose.

>

> You do seem to get a lot of uneducated opinions; where do you go for advice?

>

> Jim H. White SSC

[Guest guest]

I'm still working on my attic! Anyway, foam across attic floor is a little

steep. I may do it anyway but have another idea I thought I'd put out here.

I have had air sealing done and attic is otherwise clean but there is some odor,

so thinking of spray painting attic floor and maybe rafters, not sure of

rafters..think odor may be more from floor, lathe and plaster is pretty dark

gray so think mold maybe from humidity on humid days. It's already been

vacuumed.

(Incidentally I think darkness of lathe and plaster occured after I left a sheet

of plastic across attic floor to catch some debris from work and then forgot to

take it up right away. I didn't leave it down long enough for any major

problems but I noticed the creamy colored plaster change to grey so...!)

Anyway, after spray painting floor (to protect attic from humidity from outdoor

air coming in ventilation...I think ventilating attics is not a good idea (no

problems in attic before I ventiliated), anyway after painting, thinking of

using the s Manfield formaldehyde free batt insulation between the floor

boards and then putting a perforated aluminum foil blanket over the batt

insulation, one to keep it clean and second for the added insulating value of

reflecting heat off of attic floor, and in winter reflecting heat of house back

in to house. I have to see if this is less money than foaming floor. s

Manfield has the poly wrapped fiberglass batts which are nice but I can't use

them with the thermal blanket because it would block the perforations in the

s Manfield product. I'd have to use their regular unwrapped batts but I

figure the aluminum blanket would keep the fiberglass from moving about. I

think the aluminum blanket has to be stapled or tacked down.

I'm getting a price on this this week so I don't know if it will end up less

expensive than foaming yet but thought I'd put this out in group.

[Guest guest]

Hi Barb

Bill Holloway here.

I wouldn’t use the foil in the manner you discribe (horizontal). Dust – vented attic or not – will gradually degrade the effectivness of the foil. Additionally

radiant barriers/foil work best if the down side has an air space. This is why you typically install them to the underside of the rafters. Do not waste time making the foil installation super tidy, Just staple across joists, ignore the stray hole or bit

of damage. Ultimately those installation scars will have a so little effect on the overall attic performance as to be insignificant in the overall attics performance.

Since you have air sealed the attic be sure batts (if that is how you ultimately go) are about the same height as the joists. Then roll another layer crosswise

to the joists. Thickness is up to you – R-13 is about as thin as you will find is my guess. This layer atop the joists now decouples the joists as a thermal bypass from the ceiling. Just like using Blue board under the exterior wall sheathing.

I remember that someone was concerned with walking in the attic with this approach. How often do you intend to crawl around in the attic? For storage build a platform

by nailing plywood – never osb or particle board – to the joists and just don’t insulate there (under neath of course).

Hopefully this helps

Bill

If you go with foam – which product? There are closed cell foams that can hit almost R7/in on average when installed more than an inch thick. Open cell products

tend to be less than R4/in when installed more than an inch thick.

From: iequality [mailto:iequality ]

On Behalf Of barb b w

Sent: Friday, March 09, 2012 2:36 AM

To: iequality

Subject: Attic insulation

I'm still working on my attic! Anyway, foam across attic floor is a little steep. I may do it anyway but have another idea I thought I'd put out here.

I have had air sealing done and attic is otherwise clean but there is some odor, so thinking of spray painting attic floor and maybe rafters, not sure of rafters..think odor may be more from floor, lathe and plaster is pretty dark gray so think mold maybe from

humidity on humid days. It's already been vacuumed.

(Incidentally I think darkness of lathe and plaster occured after I left a sheet of plastic across attic floor to catch some debris from work and then forgot to take it up right away. I didn't leave it down long enough for any major problems but I noticed the

creamy colored plaster change to grey so...!)

Anyway, after spray painting floor (to protect attic from humidity from outdoor air coming in ventilation...I think ventilating attics is not a good idea (no problems in attic before I ventiliated), anyway after painting, thinking of using the s Manfield

formaldehyde free batt insulation between the floor boards and then putting a perforated aluminum foil blanket over the batt insulation, one to keep it clean and second for the added insulating value of reflecting heat off of attic floor, and in winter reflecting

heat of house back in to house. I have to see if this is less money than foaming floor. s Manfield has the poly wrapped fiberglass batts which are nice but I can't use them with the thermal blanket because it would block the perforations in the s Manfield

product. I'd have to use their regular unwrapped batts but I figure the aluminum blanket would keep the fiberglass from moving about. I think the aluminum blanket has to be stapled or tacked down.

I'm getting a price on this this week so I don't know if it will end up less expensive than foaming yet but thought I'd put this out in group.

[Guest guest]

Hi Bill, I don't want exposed fiberglass because as it collects dust it becomes a home for mold growth and degrading exposed to air, dries out, etc. The thermal blanket of perforated foil would be over an air space. The air space would be under it, filled w fiberglass. Fiberglass has plenty of air space in it. Foam, closed cell. Getting a bid on it this week. Getting around. I had a walk way built down the length of attic. The insulation can easily go under it. I don't intend to go over the floor joists right now. Perhaps some day a new owner can put more insulation in and have trouble walking but I'd rather pay the higher heat bills and not have the fiberglass or chemicals in the house. Subject: RE: Attic insulationTo: "'iequality '" <iequality >Date: Monday, March 12, 2012, 1:49 PM

Hi Barb Bill Holloway here. I wouldn’t use the foil in the manner you discribe (horizontal). Dust – vented attic or not – will gradually degrade the effectivness of the foil. Additionally

radiant barriers/foil work best if the down side has an air space. This is why you typically install them to the underside of the rafters. Do not waste time making the foil installation super tidy, Just staple across joists, ignore the stray hole or bit

of damage. Ultimately those installation scars will have a so little effect on the overall attic performance as to be insignificant in the overall attics performance.

Since you have air sealed the attic be sure batts (if that is how you ultimately go) are about the same height as the joists. Then roll another layer crosswise

to the joists. Thickness is up to you – R-13 is about as thin as you will find is my guess. This layer atop the joists now decouples the joists as a thermal bypass from the ceiling. Just like using Blue board under the exterior wall sheathing.

I remember that someone was concerned with walking in the attic with this approach. How often do you intend to crawl around in the attic? For storage build a platform

by nailing plywood – never osb or particle board – to the joists and just don’t insulate there (under neath of course). Hopefully this helps Bill If you go with foam – which product? There are closed cell foams that can hit almost R7/in on average when installed more than an inch thick. Open cell products

tend to be less than R4/in when installed more than an inch thick.

From: iequality [mailto:iequality ]

On Behalf Of barb b w

Sent: Friday, March 09, 2012 2:36 AM

To: iequality

Subject: Attic insulation

I'm still working on my attic! Anyway, foam across attic floor is a little steep. I may do it anyway but have another idea I thought I'd put out here.

I have had air sealing done and attic is otherwise clean but there is some odor, so thinking of spray painting attic floor and maybe rafters, not sure of rafters..think odor may be more from floor, lathe and plaster is pretty dark gray so think mold maybe from

humidity on humid days. It's already been vacuumed.

(Incidentally I think darkness of lathe and plaster occured after I left a sheet of plastic across attic floor to catch some debris from work and then forgot to take it up right away. I didn't leave it down long enough for any major problems but I noticed the

creamy colored plaster change to grey so...!)

Anyway, after spray painting floor (to protect attic from humidity from outdoor air coming in ventilation...I think ventilating attics is not a good idea (no problems in attic before I ventiliated), anyway after painting, thinking of using the s Manfield

formaldehyde free batt insulation between the floor boards and then putting a perforated aluminum foil blanket over the batt insulation, one to keep it clean and second for the added insulating value of reflecting heat off of attic floor, and in winter reflecting

heat of house back in to house. I have to see if this is less money than foaming floor. s Manfield has the poly wrapped fiberglass batts which are nice but I can't use them with the thermal blanket because it would block the perforations in the s Manfield

product. I'd have to use their regular unwrapped batts but I figure the aluminum blanket would keep the fiberglass from moving about. I think the aluminum blanket has to be stapled or tacked down.

I'm getting a price on this this week so I don't know if it will end up less expensive than foaming yet but thought I'd put this out in group.