Insulation question

I am currently finishing a bonus room over a garage right now. I am planning on doing the insulation myself. I have been researching prices and I have noticed how much more money R-30 and R-38 batts are compared to the R-19 insulation. The question that I had was that there are a few places that I was planning on putting R-30 and R-38 batts, would I be able to double up the R-19 batts and put two of them on top of each other to create the same insulation size and R value as the R-38 batts would create? Would this be up to code or would this not be allowed? Just wondering, please let me know anything that you can, thanks!

Zach

 

Not sure about the code part of this in your area, but I think that 2 R-19s would be pretty close to, if not equal to, an R-38. At least that's what the insulation salesman said.

One thing to consider: if the R-19 Batts are faced, you should remove the vapor barrier (kraft paper??) from the batt placed on top of the other batt.
In other words, you want to avoid (vapor barrier) Batt-vapor barrier-batt, as that could trap moisture in the one batt-not good for insulation.

Good Luck with your project.

 

Mike,

Thanks for the response, do they not sell R-19 23 inch wide batt rolls unfaced? Just wondering, I think that if they do come faced that I would remove the faced portion so that there would not be the vapor barrier. Thanks again for the response.

Zach

 

Don't know about your area, but right now at Home Depot, R30 unfaced insulation is substantially cheaper per sq ft than R19 - only $12.50 per 25x16" roll, something like $.40 sq ft...

 

The pink insulation in batt form, unless R-15, is low density, comes with convective loops when the temp's change: http://forum.doityourself.com/insula...oose-fill.html I’d go with a heavier density application (1.8# density) to stop the loops…..

Gary