Air sealing plank attic floor
I have a house in climate zone 5 built in 1918. The attic is approx 728 sq ft with a single peak around 8 ft and tapers down to all edges. It is roughly a square with a staircase and a single dormer jutting out front. There is approx 6 inches of >30 year old loose fill cellulose with a plank floor on top of it. I know the ultimate best thing to do would be to rip up the plank floor, vacuum out all of the old insulation and air seal but we aren’t planning on being in this house more than a couple of years and it’s hard for me to give up this amount of prep and time with my current situation.
I can seal around my bathroom vent fan, chimney, and plumbing stack with the appropriate materials but my next step planned was just to blow in additional cellulose on top of the plank floor to achieve a total of r60. I’m estimating about R20 with the old cellulose.
However, would putting down a house wrap and taping the seams be advantageous in achieving a better air barrier? Would I run into issues with having the plaster ceilings below, old cellulose, new housewrap, and then new cellulose? That doesn’t seem to be too much work – certainly less than tearing up all of the plank floor and having to dispose of all of the wood in addition to renting the insulation vacuum and disposing of all of that too.
Or do I just go forward with super beefing up the existing insulation with additional blown in cellulose and call it a day? I’m going to have a roofer/siding company come out and check out ventilation in the attic – The plank floor extends all the way out and there are no baffles so I’m guessing the attic intake ventilation is just through being old and leaky! The soffits do have the perforations but I’m guessing this was just because that’s the soffit material that the siding company had – either that or they’re useless right now anyway as they aren’t ventilating into the attic well with the cellulose and plank floor in the way.
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