Townhouse common wall upgrades
I had a kitchen fire in my Gaithersburg, Maryland townhouse (about 20 miles north of Washington DC). The insurance is going to pay to have the walls on the first floor removed and have the insulation replaced. The townhouse was built as part of a quad in 1986, with the main wall facing south, and east and west walls connected to neighbors, and half of my northern wall is connected to my neighbor behind me (the other half faces the central atrium). The townhouse was built in 1986, and as best as I can tell, the common walls were built using two layers of fire blocking drywall and no insulation, with a 6 inch gap between townhouses.
The south and northern walls were insulated with fiberglass batts in the typical manner (poorly), so I was planning on replacing the insulation with dense pack cellulose, and while I had them there, have them insulate the un-insulated walls as well. Maryland is currently under 2015 IECC.
I have search the internet for these answers, but come up empty. Does 2015 IECC (or other building codes) require heated common walls to be insulated, and if it does, does it require fire damage walls built in 1986 to be upgraded to the current code. My second questions is if I do insulated the currently un-insulated walls, is there any thing special I need to do or be worry about.
Carl
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Replies
Carl,
I can't answer your question about insulation requirements for party walls, but I do know that party walls need to be fire-rated. I also know that it's possible for insulated walls to achieve the required fire ratings; see, for example, this document: Not All Party Walls
Are Built Equal.
When in doubt, you should contact an architect or your local code authority.