Best way to retrofit attic insulation, subfloor options?
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I’m looking for feedback on the best approach to increase the overall R value of insulation in the attic of my home, while still maintaining my ability to move around within the attic in case I need to run wires, etc. – perhaps even use it for storage.
It’s a 1950’s era ranch in zone 5. Currently, there is a thin paper-faced batt of fiberglass with blown cellulose over that up to the height of the floor joists. There isn’t a lot of headroom – even at the peak – but I can drop some planks down and crawl around without disturbing the existing insulation when I have reason to. If I were to increase the level of cellulose, I’d basically have to swim through it.
I’m considering putting down a plywood or osb ‘run way’ down the middle of the house with loose cellulose on either side. Should I just put cellulose batts over the subfloor? I could pull them up and replcae them if needed. Another thought was rigid XPS sheets first to get the desired R value, then subfloor over that, though that’s a lot of have to pull up if I should ever need to get below it.
Does anyone have a better solution? Would I run into moisture issues by putting XPS over top of blown cellulose?
Thanks for your advice.
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Replies
Christopher,
Just install new 2x6s, 24 inches on center, on top of and perpendicular to the existing joists. Install the new 2x6s to extend the width of your desired runway. Then you can blow 5.5 more inches of cellulose in your attic. Finish up the job by installing plywood or OSB on the runway.