[Greenbuilding] insulating around windows... best practice

Frank Tettemer frank at livingsol.com
Thu Sep 5 05:37:53 MDT 2013

Hi Reuben,

I like using an on-site mix of Hempcrete, mixed with about 25% Perlite. 
This is probably a slower install than either spray foam or backer rods.
And it takes a bit of practice and technique to stuff it into the cavity 
between the window and rough stud opening. I've tried, somewhat 
successfully, to use a pastry bag, or cake decorators bag, with a long 
nozzle to initially fill the space. Then, applying pressureto the 
filling, to squeeze out any air pockets, and then smoothing off the 
surface, makes a good seal. A variety of slender masonry pointing 
trowels will do the job.

More labour than buying cans of spray foam. However, this uses very 
little lime and portland in the mix, and the hemp hurds are a renewable 
Perlite is admittedly a mined resource but worth it, as it adds some 
R-value to the hempcrete mix.

Best of all, there's no immediate use of petrochemicals in the mix 
materials, and no off-gassing, during application or through it's life 

Frank Tettemer
Living Sol ~ Building and Design
613 756 3884

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