0 Helpful?

How to insulate roof?

Hi,

I am renovating this old porch addition and want to insulate it properly. There must have been some moisture issues before because some of the OSB has what looks to be mold or something moisture related. Luckily it doesn't seem to smell and it still feels firm. I'm speaking with a spray foam installer today but I have the feeling that cost for the size of the ceiling (145sq.ft.) is going to be rather... expensive.

These are 2x4 rafters on OSB with a layer of roofing felt and then a corrugated locking steel roof. There should be some ventilation due to the nature of the roof. I've attached some photos. My thoughts are 2x4 batts with a layer of 6mil poly and then 5/8" drywall. The walls have 1" foam on the outside w/ stucco.

If I don't go with spray foam what's my next best option for method and materials?

Thanks for your help.

IMG_20121116_163518.jpg40.72 KB
IMG_20121202_121640.jpg1.44 MB
Asked by benjammin p
Posted Dec 4, 2012 4:47 PM ET
Edited Dec 4, 2012 4:59 PM ET

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.

Benjamin,
I suggest that you read this article: How to Build an Insulated Cathedral Ceiling.

Answered by Martin Holladay, GBA Advisor
Posted Dec 4, 2012 4:57 PM ET

Other Questions in Energy efficiency and durability

Basement is too cold, need help in insulation

In Energy efficiency and durability | Asked by Amit Jindal | Feb 16, 15

Why is it so trendy to hate on radiant in-floor heat?

In Mechanicals | Asked by Josh Jipson | Mar 1, 15

Spray foam optimal or does another solution exist?

In Energy efficiency and durability | Asked by Todd Munson | Mar 6, 15

PERSIST - Vapor-open or vapor-closed insulation and WRB?

In General questions | Asked by brad hardie | Mar 6, 15

Membrain in walls, poly in attic. OK or not?

In Energy efficiency and durability | Asked by Alex House | Mar 6, 15
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!