Helpful? 0

Whether it's worth removing Sheetrock in closets to spray foam

Dear all, I have a Cape Cod and plan on insulating the second floor by air sealing with 2 inches of spray foam and then finishing with 3.5 inches of Ultra Touch cotton batts to fill the 6 inch rafters.

There are a few closets that are sheetrocked and will take a great effort to remove. Since the closets have doors thus preventing most of warm air to condense against the roof after dense packing with cellulose should I have any concerns? Ideally I would like to air seal whole of second floor but ripping out all the Sheetrock is a large task.

Mike

Asked by Michael H.
Posted Thu, 01/03/2013 - 00:04
Edited Thu, 01/03/2013 - 06:22

Tags:

2 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Mike,
I'm sorry to be the bearer of bad news, but here it is: it's time to demolish the drywall in your closets.

It sounds like you have decided to use the flash-and-batt approach to insulate your sloped roof assembly. If you do this, you will end up with an unvented cathedral ceiling. I suggest that you read the following article: How to Build an Insulated Cathedral Ceiling.

Your two inches of spray foam will provide an R-value of about R-13. That is adequate in Climate Zones 1, 2, and 3, as well as Zone 4C. However, in Zone 4A, 4B, or anywhere colder, you will need more spray foam. The details are in the article I linked to.

Answered by Martin Holladay, GBA Advisor
Posted Thu, 01/03/2013 - 06:28
Edited Thu, 01/03/2013 - 06:30.

2.
Helpful? 0

Thanks for your feedback Martin. I read the article and gained more insight. I am in zone 4a so my flash and batt option will yield r-26. I figure this should suffice until I add rigid board when I replace my roof in the future. Right now I close off the attic which is unused using a weatherstripped door so no heat from downstairs will seep to the roof and condense against the roof. Before I did this I had ice dams but not since. I just figured that sealing the closet doors and dense packing the closet ceilings would be better than the current setup hus averting condensation enough to avoid major damage until I redo the roof and add rigid foam board which will ultimately solidify everything. I know the theory behind why closed cell should be used on the roof to air seal but also comparing with what I have now and feel that logically it should be fine.

Answered by Michael H.
Posted Thu, 01/03/2013 - 08:32

Other Questions in General questions

U value of double windows for sound proofing?

In Green building techniques | Asked by Ryan Griffin | Nov 26, 14

Brands of HRV?

In Mechanicals | Asked by stephen sheehy | Nov 17, 14

Any good thoughts on Drolet wood stoves?

In Energy efficiency and durability | Asked by Paul Kuenn | Nov 23, 14

Window flashing and trim with exterior rockwool

In General questions | Asked by colin slade | Nov 25, 14

What's a good damper for a bath fan/range hood vent?

In Mechanicals | Asked by Nathaniel G | Nov 23, 14
Register for a free account and join the conversation


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