Insulating an attic? - DIY Chatroom

kcrossley2 · 05-05-2007, 03:32 PM

I'm getting ready to finish a third-floor, walk-up attic. Currently, there is no insulation, except for a few batts that suround the walls of the stairwell leading to the conditioned second floor space.

What type of insulation should I use in the vaulted rafters above the drywall? What about the walls? What R-values should I use? (I live in eastern VA) And lastly, should I purchase faced or unfaced insulation and which way should the facing, well face?

Thanks,
Kelly

p.s. Here's a cool D.O.E. insulation calculator I found: http://www.ornl.gov/~roofs/Zip/ZipHome.html

**AtlanticWBConst.** · 05-05-2007, 04:00 PM

Quote:

Originally Posted by kcrossley2

I'm getting ready to finish a third-floor, walk-up attic. Currently, there is no insulation, except for a few batts that suround the walls of the stairwell leading to the conditioned second floor space.

What type of insulation should I use in the vaulted rafters above the drywall? What about the walls? What R-values should I use? (I live in eastern VA) And lastly, should I purchase faced or unfaced insulation and which way should the facing, well face?

Thanks,
Kelly

p.s. Here's a cool D.O.E. insulation calculator I found: http://www.ornl.gov/~roofs/Zip/ZipHome.html

Hi Kelly,

This can be affected by what source you plan on heating the area with and what is required by code for your region. You should check with your local building dept.

Either way, you need to install rafter vent in the rafter bays for moist air circulation and use a kraft faced insulation with the paper facing the warm area.

Ron6519 · 05-05-2007, 05:21 PM

Put in as much insulation as is required by the region. To do this you might need to add to the roof joists. You need to leave at least a 1" gap between the insulation and the roof sheathing for air flow. I would leave a common area at the top where all the bays open into. Make sure you have adequate ventilation to exhaust the super heated air or your cooling costs will be, well, through the roof(pun intended).
I personnally like unfaced insulation and a 6 mil plastic barrier. The barrier has less leaks, if properly installed.
Ron

kcrossley2 · 05-05-2007, 05:54 PM

It starting to sound like I should get a professional involved. Do you agree?

**AtlanticWBConst.** · 05-05-2007, 06:42 PM

Quote:

Originally Posted by kcrossley2

It starting to sound like I should get a professional involved. Do you agree?

No Kelly,

I think you can definitely do a job like this yourself. Contact your local building dept. and ask them about what is required in your area for this type of insulation application. Generally R-13 on the walls and knee walls. Rafters: R30 to R38

Helpful Links:

http://www.lowes.com/lowes/lkn?actio...nsulHome2.html

http://www.owenscorning.com/around/i...ishedattic.asp

Sammy · 05-05-2007, 08:54 PM

Hey Kelly!

This is a job you can do yourself for sure!

I'm finishing overlaying blown in over my attic with unfaced fiberglass.

Its a little bit of work, but most of the cost is materials. Homey and Lowes both run sales in the fall on this which is a big savings.

I'm in Va Beach.

What part of Va ya hail from?

**joasis** · 05-05-2007, 11:30 PM

And don't forget cellulose insulation, you can do it yourself, and it beats fiberglass hands down, unless you only read the fiberglass manufacturers information. www.fiberlitetech.com

**AtlanticWBConst.** · 05-06-2007, 08:57 AM

Quote:

Originally Posted by joasis

And don't forget cellulose insulation, you can do it yourself, and it beats fiberglass hands down,....

I agree with you there Joasis. We just did a another recent price comparison for a job between using the fiberglass batts and blown cellulose for an attic.....

Huge price difference and time savings.

Sammy · 05-06-2007, 10:30 AM

Blown in cellulose works great at filling all the small nooks and cracks.
I just found it easier to use the unfaced fiberglass for some of the tight areas I had to get into. Plus not having to deal with the machine rental and a second person to feed the machine. Although there is more cutting and fitting.

By working the rebates I got the price per square foot for the fiberglass to within five cents per square foot of the blown in.

**joasis** · 05-06-2007, 11:16 AM

The basic problem with fiberglass is it basically doesn't have any true insulating properties....without the kraft face, or any facing, air will easily move through the insulation.

The sprayed cellulose, while not a DIY endeavor, is tested and proven to virtually seal against air movement.