Rainscreen Over Existing Cedar Shingles
I have a 1912 house in Seattle (Marine Zone 4). In the late eighties a second story was added. The downstairs portion has cedar shingles covered with lead paint, 3/4 inch lap sheathing, mineral wool insulation in a 2×4 cavity, with intello db+ on the interior which is taped to reasonable airtightness, then furring strips, another inch of fiberglass insulation and drywall. The upstairs has more cedar shingles, tar paper, plywood sheathing, 2×6 walls with paper faced fiberglass and drywall. I have retroactively air sealed the upstairs with tescon tape and spray foam, but it is likely less airtight than the downstairs.
That’s likely more info than you need. My question is, is there any reason not to just run furring strips over the cedar shingles, using them as my rainscreen water barrier, and hang fiber cement over that?
I wish to do this in stages over the next few years, and I don’t want to deal with the mess from all the lead paint which flakes off easily when disturbed.
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