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lagarto
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# Posted: 15 Sep 2014 09:27am - Edited by: lagarto
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I stayed in a cabin in SC that I loved, and as I am ready to build mine and being a novice, I was wondering how I could copy and improve on the roof construction. It was 14' wide (24-30' long), looked like it uses 2 x 4s for rafters yet had plywood under metal roofing.Rafters did not extend over top wall plates but nailed directly to them, leaving no overhang. looked like drywall(?) on the inside ceiling looking up, yet the owner swore there was insulation between the drywall and plywood. I really liked the idea of having a vaulted ceiling in a 14' wide building, yet seemed to be very well insulated in the hot temps outside. Insulating my cabin from heat/cold here in N. florida is BIG concern, I know if I put a truss roof on it's easy to put a layer of insulation on an 8' ceiling, but I really want the insulation in the roof rafters(I'm thinking having a loft as well). So for a 14' wide cabin, would the order of material from outside to in work as: metal roof--felt paper--1/2" plywood--2 x 4 x14' rafters-prefabricated vent chutes-insulation (what is best?) ,then drywall ? I asked a construction friend and he said "yes" but he was concerned about the load on the walls without cross support on the rafters..?
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MtnDon
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# Posted: 15 Sep 2014 01:27pm
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While technically a 2x4 rafter can span the width (14 ft total span = 7 ft per rafter) with many different species, 2x4's do not have sufficient depth for effective insulation if the plan is to install between the rafters. 2x12's would.
If your friend was worried about not having rafter ties / ceiling joists to keep the wall tops from spreading that is a very valid concern. Using a structural ridge beam with column supports down to the foundation would be one method to get around that.
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lagarto
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# Posted: 15 Sep 2014 02:00pm - Edited by: lagarto
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One thing I didn't mention is that the frame of this building will have 6 x 6 PT posts either 4' or 6' apart ( can do either, have plenty of them) cemented into the ground 3'.
I'd like the cabin 2-3' off the ground (6x6 poles are plenty long) so if anyone has a link to anything similar (14' wide), with or w/o vaulted ceilings I'd appreciate it-found this one recommended on another post:
http://www.countryplans.com/jshow.com//y2k/listings/29.html
and I may just go with it....
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toyota_mdt_tech
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# Posted: 16 Sep 2014 08:48am
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Great site with lots of nice details on roof venting, be is an attic or heated living space.
http://www.finehomebuilding.com/how-to/articles/a-crash-course-in-roof-venting.aspx
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