That was a style many years ago( 1800's)- brick homes are mostly just an outside facade stacked up against a standard 16"oc wood framing covered with celotex( there other materials used now) then the brick work sitting on a bit of the sill edge on the bottom. Latest thing is preformed/cast 4'x4' panels of various designs ( river rock , bricks ect)
I'm redoing my older cape cod now. Still working out the details but I have it gutted. I had no insulation. But my rafter bays are a little bit less than 6"! The trusses start at 3.5" tall on the eave ends, and taper off to about 2 7/8" tall near the peak. Standing seam metal roof (new) on old purlins. I am thinking of using foam board like EPS, but does the first layer under the purlins need to be foil faced or anything? Since 3-4" thick seems hard to source I was thinking if double 1.5 or 2" boards. Maybe another 1.5" layer under the trusses but I don't have much headroom to work with. If I need foil faced or something for the first one, that will limit options. Going to insulate against roof and the little bit of outside wall, and make the whole space conditioned. Everything will be sealed with spray foam, I got a case of it and gun, and then sheetrock.
That's a solid plan. You might want foil face on the outer layer but it's just fine to go with more than one board to make the thickness. That's what I plan on doing when I "wrap" my house with poly-iso too.
That tin roof is going to sweat, better to have sprayfoamed - no air gap to allow condensation. Ya it cost more- its one of those pay now or pay more later when ya have to rip it all out due to water stains on the interior sheet rock.
I agree with chris. 6 inches 2 pound spray foam should equal r42, call around Mt dealer will do it installed 73 cents a board foot. 1 inch thick. pink is almost as expensive
I was advised not to spray foam against a metal roof. And its not in the budget. If I were remodeling the entire upstairs with access to the whole roof, and was going to stay in the home then I'd consider. But I'm looking at best bang for buck. Just not sure if I need anything special like the foil face under the roof purlins, or if the plain white EPS sheets will be OK (cheapest price for r value I'd seen). 73 cents a foot doesn't sound too bad though maybe I'll check some more places. Would solve the issues of having to cut all these sheets to fit.
I am not qualified to answer any insulation questions. Sorry. I like your concept, I'd like to do something like that also. IMO I dont think 2 7/8 of any insulation is enough to keep your tin roof from condensating.
Plan is (if I don't need foil face or something special) to put up 2 layers between the rafters, probably 1.5" and 2" EPS. That would be 3.5" and flush with the rafter at the bottom, and leave a slight gap as the rafter tapers slightly at the top (could fill with spray foam). Then under of the trusses I'd do another layer of 1.5", with a total thickness then of 5" which would be R20 if I use the cheapest white EPS boards. Everything will be spray foamed around the edges so hopefully a tight air seal. Sorry I may have not explained it the best. Maybe a diagram would be easier to explain. I just got to get this taken care of I was hoping to have this done last week actually!
I just dont know enough to be a help here. And I would hate to tell you its a great idea then have it mold later. Ive been in construction all my life. But i dont know a thing about heat transfer and insulation.
without knowing what products, a good lumber yard will have pamphlets, I do not see enough airflow to keep condensation out. I would not want to give you bad advice.. r21, is minimum wall code here. I would look up recommendations at a contractors store read pamphlets and make best decision in budget. good luck
oh I would not spray to ceiling, pink Styrofoam you staple to rafters to get air up soffet, vent to ridge vent.
Plenty of people are doing what they call "hot roofs" with the insulation right up against the bottom side of the roof purlins and/or decking with both tin and conventional roofing material. Then the attic becomes a conditioned space of course.
yes Sam lots of people do it I did it on a section of unvented roof at my house. first, it will void most warranty and it needs to be completely sealed again moisture to prevent mold. it is contrary to regular thinking, I liked the principles involved but assumed to do it right was outside his budget...
tstew, I understand, making the best of a bad situation for your son. I would recommend going to the green building council website and doing some research. most of the time they say not to spray metal because nobody knows how they will react to each other over time. everyone used to wrap pressure treated with metal until the changed chemicals in put and had problems. I have not figured out how to do links on tablet but just looked it up and good luck
Yep done lots of my research there. Hardly any info in the web about insulating cathedral ceilings with purlins and metal roof. Could be that the purlins instead of sheathing doesn't matter, I'm not sure. But I've read at least a few posts where someone is talking about a similar setup and someone else chimes in and says not to on an unsheathed metal roof, etc. More similar setup to a pole barn than a home I guess, so I've been scouring garage and barn forums too. Often times though I can't do what others suggest since my rafter bays are so shallow. I can't wait to sell this place, and hope to build an efficient home in the future! Retrofitting is such a pain!
For the first 18.5 years I lived in my house I said I was going to demo my cape cod and build a nice house. Then when I made the last payment 1.5 years early, I realized "im not going in debt for 20-30 more years to have a big fancy house". Its paid for. And I want to retire some day... Soon!
TD, congrats on paying it off and early to boot So now you can afford the upgrades but then the kids leave yards don't need them..
td, right now house need updates adding closets, kitchen space etc once kids are grown and leave a bigger kitchen and more closets less needed for 2 people..
