I am considering adding insulation to my attic; the home is in Southern Rhode Island. The ceiling joist are 2×8, with Kraft-faced fiberglas batts installed between. I basically have two questions: I have read (newspaper articles, home improvement mags, etc.) that applying another layer of fiberglas (unfaced, of course) perpendicular to the joists is acceptable (true?). Also, with oil-fired hot water baseboard heat and retrofitted central AC, will I recover the insulation costs (material only) for approximately 1000 square feet, of whatever appropriate thickness, soon enough to make it worth the cost.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
There's a constant source of clean water for you to use, and all you have to do is collect it.
Featured Video
SawStop's Portable Tablesaw is Bigger and Better Than BeforeHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
If you are going to go with FG perpendicular to to original is the way to go. I would suggest using cellulose to add R-value and cap the existing FG. It will fill in any gaps and will give you a more consistent resistance to heat transfer.
Check out Oak Ridge National Laboratory for third party insulation testing.
Insulating will save you money unless you are very well insulated now, the rule of diminishing returns.
Doing a total heat loss calculation for your home is about the only way of telling how long it will take to pay back your investment.
Blow in cellulose. I spent $500 blowing cells over loose fiberglass last summer and and I've saved over that amount just in the heating season so far not counting the AC season. Took me four hours with a helper including buying materials and taking the machine back. Plus it doesn't itch.
Birth, school, work, death.....................
http://grantlogan.net/
If you ever have to access, or store stuff in your attic, don' bother. Once you compress, push, shove, and move it around you won't accomplish much.
I remember reading about attic insulation studies in Minnesota. Fiberglass batts were only as good as their weakest point of installation---the seams. My vote is blown in cellulose, because it stops the air movement.
Whether you use FG or cellulose you have an opportunity now while you only have batts on your attic floor. Getting access to all the holes through the attic floor plane is much easier now than after you add insulation. You should find all the penetrations (plumbing vent stacks, chases, wiring penetrations, ceiling lights) and seal them with foam or caulking, using high-temperature tolerant materials where appropriate. Also you can seal the top plate of each partition wall and the exterior walls with foam.
Much harder to do all that after you blow cellulose.
The taunton insulation & weatherization book is a good resource on all this.
Best of luck.
As for recovering your material costs I'll tell you my experience this winter. I tore out the brown fiber board off the inside of my exterior wall ten feet away from my thermastat no existing insulation, installed r-19 fiberglass, replaced two windows and one door, redrywalled and cased the wall out. Had just over a 1,000 dollars in materials. Last two heat bills were $75-$80 lower than before the improvement. So in about 10 months that will be paid for, if gas prices stay put for next year-yeah right. Kind of rewarding to see how a little work affects your home when that next heat bill shows up almost a hundred bucks cheaper.
AA Insulation used to blow all our cellulose.. give Angelo a call
we blow our own now.. and plug those holes with foam before you cap your atticMike Smith Rhode Island : Design / Build / Repair / Restore