Behind those walls

Gordy

Upon doing my shower recon one wall is exterior. Now I have insulation details answered that were sketchy. Anyone ever here of Balsam Wool insulation. Well I got it in my walls.



 May be helpful when making wall insulation assumptions in heatloss calcs.



Basically it is fire treated wood products wrapped both sides, and edges in asphalt impregnated kraft paper about 5# felt consistency.  Actually it was installed quite nicely. The perimeter of the batts are nailed every 4" sides top, and bottom.  Man they used a lot of nails back then



 Problem with the batt design it resembles a pillow so edges are thinner, and poofy in the middle. So at best the batt is an r-5 in the middle 2" thick, but its perimeter in the stud bay is about as air tight as you could get in the 50's. You dont get the convection loop inside the batt like a fiberglass batt does..

<img src="http://inspectapedia.com/sickhouse/asbestos/BalsamWoolInsul011DJFss.jpg" width="320" height="240" alt="photo of balsam wool building insulation" />



Gordy

STEVEusaPA

Thats a new one for me.....

Just make sure there's no asbestos in there.  Sounds like a poor insulator.  If you got it exposed, youre probably better off yanking it and redoing it with regular batts, and continuous vapor barrier for the bathroom.

Gordy

Wood product

Hence the name balsam wool. No asbestos.  Still fire proof except the vapor barrier poof.

kcopp

Those are....

pretty popular around here (NH)  in house that age. It was better than nothing. I supose the fireproof thing was to help if ballon framing was involved. FWIW,  I would remove it and fill the cavity w/ polyiso board and some spray foam... @ 3.5" that will give you an R-24.5.

Mark Eatherton

I agree with Kevin...

NOW is an opportune time to yank the low R value insulation, and replace it with some super duper R valued foam.



Bear in mind the need for avoiding/eliminating vapor.



ME

Paul48

Use

urethane foam, especially in a shower wall. It's closed-cell and will not absorb water. It's pricey, but for a small area,it's well worth it.If you have any doubts about its insulation value, pour boiling water in a 1/8" thick styro-foam cup.It's barely warm on the outside.

Jean-David Beyer

pour boiling water in a 1/8" thick styro-foam cup

Just do not put any lemon juice in there with the boiling water. The cups dissolve pretty quickly (tens of minutes, not seconds). At least if there is a tea bag in there too. I suspect polyurethane foam would resist lemon juice or other weak acids better. Carbon dioxide dissolved in water is a weak acid. I never tried dissolving cups with it though.

Paul48

I

had an installer get kinda indignant with me for that mistake....It's urethane, not polyurethane......Like I should know the difference,or care, for that matter.

Gordy

Replace insulation

Yeah deffinetly Just wish it was more than 3 stud bays. Should also note that the copper tubing in the pic is the return for the ceiling radiant loop. One must be surgical about demolishion at times.



Gordy

SWEI

urethane

Is a monomer - not much use in the real world.  Polymers (long chains of linked monomers) are.