DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Building & Construction (http://www.diychatroom.com/f19/)
-   -   Another insulating a cathedral ceiling question. (http://www.diychatroom.com/f19/another-insulating-cathedral-ceiling-question-72966/)

zachalyse 06-06-2010 10:35 AM

Another insulating a cathedral ceiling question.
 
First off. This is only a seasonal camp. I'm not interested in going the most expensive route. ie. spray foam, cellulose, etc.

I've removed a portion of the joist ties and will be adding a ridge beam for support. The current roof framing is 2 x 6. soffits are completely blocked off and foam sealed. There is no ridge venting that I can tell. Without getting into some major labor intensive changes what would my easiest options for insulating be?

If I vent, how involved is it to open both ends (eve and ridge). I do realize that the last thing I want is airflow directly entering the fiberglass.

Where it is seasonal use only (maybe 12 +/- weekends a year and 1 or 2 weeks), what are the chances of condensation and moisture being a problem if I just insulated the entire cavity with high density r21 followed by 1" r5 foam board (no venting)?

The camp is located in Maine and is only temperature controlled during use.

zachalyse 06-07-2010 08:05 AM

anyone?

canadaclub 06-07-2010 10:11 AM

You can purchase thin styrophoam venting material from the box stores. They come in different widths to accommodate the rafters you have. All you need to do is staple them up. Keeps the fiberglass from contacting the wood and provides an air space between the insulation and the roof deck. I've usually run these right from the soffit up to the roof cavity but since your soffits are blocked I don't imagine that will be an issue? (second opinion anyone?)

zachalyse 06-07-2010 10:43 AM

Quote:

Originally Posted by canadaclub (Post 452434)
You can purchase thin styrophoam venting material from the box stores. They come in different widths to accommodate the rafters you have. All you need to do is staple them up. Keeps the fiberglass from contacting the wood and provides an air space between the insulation and the roof deck. I've usually run these right from the soffit up to the roof cavity but since your soffits are blocked I don't imagine that will be an issue? (second opinion anyone?)

So I don't need airflow? Just a cavity?

canadaclub 06-07-2010 10:48 AM

I believe airflow is best but may want to get another opinion since that is the only way I have ever done it. Maybe someone out there has just gone with a cavity? Also, the cavity would be open at the ridge so its not like its sealed.

rtoni 06-07-2010 01:17 PM

just another DIY here but from what I understand if you're going to insulate then you either have to ensure that no air migrates to underside of roof deck (e.g. use spray foam direct to sheathing to completely seal it off) or you have to allow any air that does migrate to escape (hence the need to open soffits and ridge and use something like the durovent styrofoam or similar, stapled to underside between rafters).

here's what I did on my place - used circular saw up at the peak, cut @ 1-1/2" either side of the ridge, stapled galv hardware cloth (screening) along the entire run (critter proof) then ridge cap to cover it off. At the soffits, I used a 1-1/4" spade bit to drill out a few holes in the blocking in each bay between rafters (close to the underside of the sheeting) - covered these with the h/w cloth as well to keep critters and bugs out. Inside - foam vents stapled up to roof deck from soffit to peak.

It sounds crazy labor intensive and it is tedious but with a bit of determination (and some good drill bits, saw blades, etc.) I did all the prep work myself in @ 2 days with @ $200 invested in materials (not including the insulation of course). I figure that's a lot cheaper than a new roof, should the rot set in otherwise.

not sure if that helps...


All times are GMT -5. The time now is 04:24 AM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved