I have chinked the outside with weather all chinking over grip strip and am about to chink the inside. I would like to fill space between the backer strips. White Styrofoam has been suggested is this the material you suggest?
waterloop Changed status to publish April 2, 2024
Do not use white foam board. It gives off formaldehyde gas and will cause the chink to bubble. Use pink fiber glass if you must. The dead air space is a good insulator as it is.