Insulating a Bunkie Roof

Question Icon
Posted by: from Peterborough
5/15/2011 at 6:32:53 PM

Greetings. I'm looking at insulating my bunkie roof. There is no attic and the trusses are made of 2x4's. The roof is shingled. I am interested in preserving space so after insulating I would like to nail pine boards to the 2x4's. I'm just not sure whether I should use a strofoam, say 2 inch thick and whether I need a vapour barrier between the foam and the pine boards.

Your comments would be appreciated.



User Icon
Dave in Oshawa
Date/Time5/20/2011 at 12:06:01 PM

Hi Terry,

I guess you wanted an answer before the long weekend, huh? In terms of insulation and energy conservation, some is better than none. Depending on the styrofoam product you want to use, it may act as a vapour barrier on its own. The blue or pink stuff with the ship lapped joints (no products mentioned intentionally) will work. But there is a big caution with this method: without providing ventilation to the underside of the roof deck, you can create problems with moisture buildup, rot and/or mould. If you are very careful with your cuts to ensure they fit very tightly from rafter to rafter with no gaps, then you'll do well. If you're going to attempt this method, it's best to invest in acoustic sealant and goop up every joint before you put up the pine.

So, next option is poly vapour barrier. Cover the whole ceiling area and overlap the joints a minimum of 6" (a whole rafter bay is easier) and use acoustic sealant to seal between the flaps. But of course we've totally ignored the walls, which you shouldn't. The point I'm trying to make is you can't *just* do the ceiling. This is one of those all or nothing deals (in my opinion) otherwise any moisture will simply follow the path of least resistence. If you want more help or suggestions, email me at dave at hendersonbrothers dot ca.

Good luck with it!

~ Dave

Search the TrustedPros directory and discover the best contractors in your area.

Find your home service pro
Great renovations start with a great contractor.

Since 2004, TrustedPros has been helping homeowners find the right contractor for their home improvements and repairs.

Post Your Project

Within hours you'll be comparing offers from top-rated professionals. It's free to post and you're under no obligation to hire.

Trustedpros Inc. does not warrant the accuracy, completeness, safety, legality or usefulness of any Content, or Whether Content is Current and up-to-date, and TrustedPros Inc. Shall have no liability whatsoever with respect to your use or reliance upon any content or for content being removed or otherwise ceasing to be available. Please refer to the terms and conditions of use of this websites for more details.

Get Free Estimates

Post your project and compare offers from top-rated pros.