How many square feet of reflectix is needed?

[Pgmopar]

I am soon at the insulation portion of the reno on my 1970 13' Boler. I am wondering if anyone has the math on how many square feet of insulation is needed for it.

I plan on using reflectix insulation for the job.

Thank you.

[BARNEYCONE]

Refletix comes 4'x25' = 100 sf @ .50 per= $50 usd. Doing 16' cassie thru-out, have used one roll thus far, will require 16" roll to complete. Easy to cut, fit, work, use only their sealing tape!

[Pgmopar]

Ty very much.

[Defenestrator]

One caveat on reflectix: the R-value of ~4.5 quoted by Scamp and others is when it's used as a radiant barrier. That is, when there's several inches of airspace on the "warm" side. When sandwiched between layers, the r-value is <1 and you're better off using some sort of closed-cell foam like polyethylene or Ensolite.

[David B.]

I can not speak as to the R value of the Reflectix, but I do know that a single layer has made a huge difference under the Marine Headliner I installed.
Dave & Paula

[Pgmopar]

Perfect, not super concerned about the r factor as all of this is for one summer weekend trip per year. Then we will put it at the lake as another bunky. But it is super nice to know. Thanks everyone, I am loving the helpfulness of everyone on this site. I hope all the info pays off in completing this project.