# Improving Attic Insulation



## Fix'n it (Mar 12, 2012)

pics are way to small


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## wrbrb (Aug 18, 2020)

Fix'n it said:


> pics are way to small


Edited to expand all photos back to a large size. Previously heard it was annoying to scroll through large photos, to shrink them so people could click on them to enlarge if they wanted to. Might not be the same experience on mobile vs desktop?


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## Fix'n it (Mar 12, 2012)

wrbrb said:


> Previously heard it was annoying to scroll through large photos, to shrink them so people could click on them to enlarge if they wanted to.


it can be, but yours were/are not clickable. i am on pc.


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## Fix'n it (Mar 12, 2012)

Fill gaps like this in the ceiling with foam? = YES , all of them. with spray foam. also look for ceiling electrical box's, seal those with caulk.


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## wrbrb (Aug 18, 2020)

Will do. 

Probably most curious about stuffing the cavities at the gable end and soffit ends, if that’s a good idea or not, and what the strange double-faced mulch-like insulation is. Maybe state of the art in 1952?

Any general comments on the process outlined in my original post would also be really appreciated.


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## Fix'n it (Mar 12, 2012)

you say its balloon. my understanding is those should be closed up, top and bottom. but first, is there any insulation in the walls ? do you have plaster & lathe ? knob&tube ?

the sofits should have baffles sealed to the top plate.


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## Nealtw (Jun 22, 2017)

*Balsam Wool Insulation photo*
"Balsam Wool" is a wood fiber product or "cellulose" insulation that was widely used in homes and in a variety of other applications in the U.S. from at least the 1930's.
See BALSAM WOOL BATT INSULATION for details.

If you are just stuffing the wall cavity for fire protection I would use rock wool for that. 
For a walk, stand 2x6 on edge 14 1/2" apart and put insulation in there before adding the plywood. 
Are you dealing with vents, and high vents?


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## wrbrb (Aug 18, 2020)

There are no soffit vents on the outside. Probably not even room for them. Very narrow, maybe 3”, overhang on this colonial style home. Still need baffles for that? Block the cavities and then install baffles?

Plaster over rock lathe. All conduit in the Chicagoland area, no knob and tube.


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## Fix'n it (Mar 12, 2012)

i had plaster & lathe and knob & tube, removed it all. tons of new insulation and other stuff.

far sw sub chitcago, not far from the prisons.


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## wrbrb (Aug 18, 2020)

Nealtw said:


> View attachment 669973
> 
> *Balsam Wool Insulation photo*
> "Balsam Wool" is a wood fiber product or "cellulose" insulation that was widely used in homes and in a variety of other applications in the U.S. from at least the 1930's.
> ...


Thank you. That does look a lot like what I have. Glad it’s likely not asbestos.

How would you attach the 2x6 to the existing joists? Is there a specific kind of perpendicular hanger I can screw in?

As far as vents, there are gable end vents on each end fairly low… bottom of the vents (maybe 12x16” or so, two each and) are about even with the tops of the joists, so I’ll have to be careful not to cover them. There is one powered thermostatically controlled ridge vent that is currently not working so acting as a passive vent at best.

Would maybe 12” of rock wool in each cavity be okay? I do think the walls are insulated, because I found insulation in an exterior wall on the first floor while working on replacing a low voltage light switch, so hopefully that’s a decent amount of fire blocking already, just the fact that the walls are insulated which is somewhat stopping air flow?


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## wrbrb (Aug 18, 2020)

And would it be okay to go right over the top of the balsam wool in the joists with unfaced R-19 in places where it’s fairly intact?


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## Nealtw (Jun 22, 2017)

wrbrb said:


> And would it be okay to go right over the top of the balsam wool in the joists with unfaced R-19 in places where it’s fairly intact?


I have no experience with that stuff, sounds like a lot of work to take it out but you do want to look at the ceiling. 
Dealers choice I guess. 
With only top vents you really need to seal the sealing and you don't want a power vent up there. 
Don't forget the insulate and seal the hatch too. 
Screw a block between the 2x6s a little low and screw it to the joist.


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## wrbrb (Aug 18, 2020)

That would be screwed together in this way, with 6” (or 8” for 2x8s, 10” for 2x10s, etc) of insulation between the 4’ long 2x6, 3/4 or 1/2” plywood 2’x4’ on top?


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## wrbrb (Aug 18, 2020)

So maybe pull the balsam wool around light fixtures and electrical conduit, spray foam large gaps, caulk electrical boxes, both with fire proof caulk or expanding foam… then either put that back in place or throw it away. Make sure the joists all have 6” of fiberglass or rock wool in between, either over the balsam wool or in its place. Build platforms as necessary for walking around. Stuff 3 1/2” or 4” rock wool about 12” high down into cavities between studs on the perimeter on all four sides. Add second perpendicular layer of fiberglass or rock wool to get R-value up. Don’t block gable vents, insulate attic hatch cover, enjoy lower heating bills?


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## Nealtw (Jun 22, 2017)

wrbrb said:


> So maybe pull the balsam wool around light fixtures and electrical conduit, spray foam large gaps, caulk electrical boxes, both with fire proof caulk or expanding foam… then either put that back in place or throw it away. Make sure the joists all have 6” of fiberglass or rock wool in between, either over the balsam wool or in its place. Build platforms as necessary for walking around. Stuff 3 1/2” or 4” rock wool about 12” high down into cavities between studs on the perimeter on all four sides. Add second perpendicular layer of fiberglass or rock wool to get R-value up. Don’t block gable vents, insulate attic hatch cover, enjoy lower heating bills?


Plywood on top with my insulation in blue.


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## wrbrb (Aug 18, 2020)

Around the perimeter, this being balloon framed, would it make more sense to block off all the exterior wall cavities with pieces of 2x4 or rigid foam, caulking or spray foaming around that blocking, rather than stuffing insulation in there?


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## Fix'n it (Mar 12, 2012)

i think it would be better to block them off, then caulk. but, i don't "know".


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## Nealtw (Jun 22, 2017)

Blocking with wood would be the best, I think.


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## wrbrb (Aug 18, 2020)

How would I secure the pieces of 2x4 so they don’t just fall down into the wall?


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## Fix'n it (Mar 12, 2012)

predrill for toenail nails or screw. then screw on that handle. install the block. remove handle


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## Nealtw (Jun 22, 2017)

Aaa, 2x6? 1/2" drywall, plywood, OSB.


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## wrbrb (Aug 18, 2020)

2x6 hanging over the cavity with two nails or screws into the joist?


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## wrbrb (Aug 18, 2020)

Okay, I was back up there this evening and this is my modified plan:

Divide the attic in half perpendicular to the joists, to work on the west side and then the east side later. Move all existing pink fiberglass insulation running perpendicular to the joists from the west side to the east side of the attic, stacking it up as a second layer on that side and clearing the west side (this can be gradual, rolling it back one joist bay at a time).
Bag up the old balsam wool one joist bay at a time, shop vac the floor, build catwalk as I go along from north to south
Block off all the west side soffit gaps between studs with wood, foam/caulk around the blocking, same with north and south gable ends
Air seal the ceiling wherever there are penetrations with foam/caulk
Put new R19 fiberglass or R23 mineral wool ($$$) down between the 2x6 joists on the entire west side half of the attic
Put new R30 fiberglass or comparable mineral wool perpendicular to the joists as a second layer
Later, work on the east side the same way, but dispose of all the old fiberglass as well.
Realize this project is extremely labor intensive and uncomfortable, consider paying to have it done, see all the posts about expensive and sloppy work and shortage of trades people, invest in a good set of coveralls and do it myself.


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## wrbrb (Aug 18, 2020)

What are your thoughts on fiberglass vs mineral wool? I was thinking mineral wool would be better, but at twice the price I’m not sure if the benefits would be worth it. My main concern is the old roof leaking in the near future, ruining the new insulation. I thought mineral wool was completely “water proof” but am reading some things that it might contain additives that end up preventing it from drying out in a “clean” way. I don’t have any experience with leaky roofs or wet insulation, but am anticipating getting this experience eventually and having to deal with it.


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## Fix'n it (Mar 12, 2012)

i did all of my walls with roxul. cellulose on the ceiling


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## Nealtw (Jun 22, 2017)

Neither will protect drywall from getting wet.


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## wrbrb (Aug 18, 2020)

Nealtw said:


> Neither will protect drywall from getting wet.


I'm not concerned about the drywall, just about being able to re-use (continue to use) the insulation if the roof does leak. I assume that would be fairly isolated when it begins, though, so if I catch the leak I would only have to replace a small amount of insulation. I'm really on the fence about whether or not the mineral wool is worth the price difference. Leaning toward fiberglass due to cost.


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## Nealtw (Jun 22, 2017)

wrbrb said:


> I'm not concerned about the drywall, just about being able to re-use (continue to use) the insulation if the roof does leak. I assume that would be fairly isolated when it begins, though, so if I catch the leak I would only have to replace a small amount of insulation. I'm really on the fence about whether or not the mineral wool is worth the price difference. Leaning toward fiberglass due to cost.


Lots of people just pull the fiberglass out and prop it up and let a little water dry out. 
I have taken out a few pieces never more than what would fit in one garbage bag. 
I always take it out because attics are dusty after a few years, maybe mold won't grow on insulation but it sure will on the dust on the insulation.


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## wrbrb (Aug 18, 2020)

I suppose the same applies to mineral wool. If only there was a supplyhouse.com for insulation...


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## Thomas Kleaton (Mar 11, 2016)

Screw metal corner braces to the 2 x 4s and then to the wall studs? Of course, you'd probably have to have some kind of handle (couple of long screws) to hold pieces up while attaching braces to wall studs.


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## wrbrb (Aug 18, 2020)

Quick follow up to this insulation on my 1952 balloon framed house in the midwest (hot and humid in summer, cold and dry in winter): for the R19 fiberglass batts between the joists after I spray foam to air seal, does it make a big difference to use faced batts face down against the attic floor (second floor rock lath and plaster ceiling) or just go unfaced? And if faced, does it need to be stapled/taped or just lay it dowb?


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