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.