Identify this insulation material?

Jsbeckton

Trying to do a room heat loss calc on my 1939 brick veneer colonial and there is a material between the brick and plaster that I am not familiar with. It’s some kind of fiber material with black paper on each side. It’s about 1” thick and a cardboard color. Attached are a few cross sectional pictures from the attic. Thanks for any help identifying this so I can estimate any R it contributes.

Jsbeckton

Pictures didn’t come through for some reason

Jamie Hall

Couldn't put a name to it. However, it most likely is a pretty decent vapour barrier, which is good. If I had to put an R value on it, I'd use the same as soft wood.

KC_Jones

My guess is Homasote.

hot_rod

I'd second the Homasote

Fred

It looks like an old style press board (mostly saw dust and glue) with a tar paper vapor barrier on each side of it.

Paul48

It's not edible Fred.....

JUGHNE

Closest thing I have seen to it is "Balsam Wool".
My parents put it in their house they built in 1940-41.
It was 1" thick, precut to fit between 16" OC studs, with nailing flaps/flanges on the edges. What they had was very fine wood "wool". Yours looks courser than theirs.
The R-value for soft woods was 3.33/inch.
R-value for shavings/sawdust might be 2.22/inch.
The paper on each side amounts to considerable R value in itself.
I would guess that you have at least that 3.3.

Their parents insulated their 1915 house with newspaper and magazines inside the wall.
Both were ahead of their times by doing so.
Firewood was "free" and oil might have been 10 cents.

JUGHNE

Google "balsam wool", batts give R 3.25/inch

Big Ed_4

Looks like rocks and debris the last contractor left ... He already lost an hammer down there .. but he save the lock ring ..

Henry

It is called tentest and was used here from the 40s to the 70s.

Mark Eatherton

It was called Cellotex (sp?) here. Not much R value to it, as Jamie said, roughly 1 per inch.

Keep flame away from it... (don't ask me how I know this)

ME

hot_rod

Lots of different brands of the stuff.

It was used as soundproofing in apartment buildings, between the units. A plumber I worked with in Montana almost burned an entire complex down by soldering near the stuff. The fire flamed up hours after the job shut down. The stuff would smolder for hours.
The asphalt coated stuff was often used as expansion joints in concrete work especially where a slab poured against a building. You see it in long sidewalks sometimes.

It was also used by the model railroaders to build roadways in their layouts. My across the street neighbor where I grew up had a large model railroad in his basement. I still remember the smell of that stuff when you would saw it.

JUGHNE

I recall seeing Celotex as a fairly new product in the 60-70's.
They sheeted houses with it before siding.

Also called "Blackjack" or punk board around here.

The HO house must have some wood studs/fir strips between the brick and plaster to hold lath for the plaster.
My guess is that we are seeing the top edge of batts of some sort.

Jsbeckton

It seems similar to a lot of the things posted but nothing is an exact match. Thinking that I am best off taking some infrared measurements and back calculating the R value of the overall walls from that.

JUGHNE

Removing an electrical outlet/switch on an outside wall has always been my best investigation portal.
Even simply with the plate removed you can determine the depth of the cavity between plaster and brick.

Often in an older house I would add outlets by cutting into the baseboard which was 6-8" tall. Less plaster cutting/repair and have wood to secure to. Also added depth for a box and maybe less brick to chisel out.
Those boxes come out easy as there might be 4 small wood screws thru the ears, you can see these by removing the plate.
A $99.00 inspection camera would let you look inside the wall.

Jsbeckton

The walls are 2x4 with no fill. This 1” fiberboard is on the outside of the studs and on the others side of that is a 1” gap then brick veneer.

I have thought about filling the cavities but don’t want to make a mess of the plaster. Did some surface/air temps tonight to try to calculate overall R value for the walls and am coming up with about R8-9 on average.

Zman

Jsbeckton said:

The walls are 2x4 with no fill. This 1” fiberboard is on the outside of the studs and on the others side of that is a 1” gap then brick veneer.



I have thought about filling the cavities but don’t want to make a mess of the plaster. Did some surface/air temps tonight to try to calculate overall R value for the walls and am coming up with about R8-9 on average.

I think that is a reasonable SWAG

hot_rod

I don't think you want to fill the space behind the brick, between the brick and the sheathing, that needs to breathe or you will have moisture issues.

Mark Eatherton

I've had brick/frame homes insulated from the outside. They drilled a 3/4" hole between the bricks immediately below teh soffit and pushed a 5/8" pipe into the hole and blew cellulose into the cavity. Check with local insulation contractors. If you were in Denver, I could give a referral. Adding insulation, when and where you can will give the biggest bang for the buck. And cellulose can breath quite well.


ME

mikeg2015

I called it beadboard in my 1925 home I had previously. It was used there in place of lath believe it or not. That house was super quiet. Stucco outside over shiplap covered in tar paper , 4” air gap then the beadboard and plaster. I estimate it performed as well as about R6. With Low E storms it was surprisingly energy efficient. I think rivaled some typical cheaply constructed new construction the same size.

Solid_Fuel_Man

Interesting, I'm in the category that the overall air-tightness of a structure has more to do.with energy efficiency than R-value alone. Id guess a brick veneer'd structure would be relatively tight compared to boarded structures of the same vintage.

Gordy

Brick needs that 1" air space for moisture /condensation drainage. That's why there is a moisture barrier on the framed wall usually 15 # felt paper before the days of Tyvek. Under the felt paper was usually the celotex fiber board. Most brick has wick rope in the bottom coarse mortar joints every so often for drainage of moisture. Brick, and stone absorb moisture, and guess where it condenses. Cold brick/stone, and warmer exterior framed wall plane. The event horizon of moisture.

Now I have seen as ME says foam, and cellulose injection. Wondering long term effects......