Rather than removing redwood siding and inserting batt insulation in non-insulated 2 X 4 framed walls, has anyone had experience with blowing in insulation or injecting 2 pound foam? (probably only one foot at a time with foam), else it would blow out the sheetrock in the interior.
I saw on This Old House when they blew in cellulose insulation from the outside. They drilled a hole about 2 feet from the floor level and another hole about 2 feet from ceiling level. They blew it in starting at the bottom until they saw the cellulose start to blow out the top hole. Then went to the top hole and blew it in until they heard the machine whine meaning it couldnt push anymore. The purpose with 2 holes was to make sure the whole cavity was filled. In your case you can take off one piece of siding for each stud cavity if its vertical siding or take off two rows at the correct heights. (That is if you have plywood/osb on the outside). The spray foam will just be too hard to fill correctly without taking down the sheetrock.
