Insulation in vaulted roof and walls in Maine
My partner and I are planning a small externally insulated shipping container home around Blue Hill Maine. There will be a vaulted or partially vaulted or possibly saltbox or gambrel roof to create sleeping loft space atop one of the containers. The 40 ft containers are planned to be staggered, parallel, with an 8 ft space between them to create a 24by40ish. Or about 960sqft, footprint. It will be a diy build and we have knocked around ideas of bringing one side of the roof down to the ground, a frame style to create a greenhouse along one side. We want to insulate and clad the exterior walls of the shipping containers to preserve precious space on the interior and allow ourselves to enjoy the industrial vibe of the metal walls inside our home.
Any ideas as to pros and cons to the: -various roof styles?
-different types of insulation as to cost and r value?
-handy tips?
-size of eaves
-truss vs rafter over the loft?
Any helpful or cautionary input welcome.
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Replies
Containers are great for temporary sites, like:
https://www.blogto.com/city/2019/04/stackt-toronto-shipping-container-market-now-open/
They are a bad idea for anything permanent.
First step is forgetting the container idea. They expensive, hard to work with, hard to insulate and limit your interior layout. Framing a house is the the easiest part, you save no labour by going container route. One of the container projects I worked on (industrial equipment), by the time it was all done with cranes, transport, engineering, modifications it would have been cheaper to site build a structure.
If you really must have the container aestetic, best to insulate on the outside with rigid foam. The type doesn't matter as the steel is an excellent air and vapor barrier. Cheapest is reclaimed roofing polyiso.
You will also need to insulate on any exposed sides including the bellow the floor. Attaching the insulation directly is possible but then you have screws poking through the walls. Probably the best bet is to weld on some additional steel that you can screw into to anchor the foam and your siding.
Also don't forger to leave space for framing in service cavities for electrical/plumbing/hvac.
Learn how to use a plasma cutter and welder. You will need it to pull off this type of project.
Rafters are easier to work with when you are looking at a cathedral ceilings for something like the loft. They are easier to site build, air seal and insulate.
Standard eaves sizing answer is to make them as big as you can, longer eaves protect the siding and foundation more than shorter ones. Right sized eaves are also a great way to shade your windows.
+1 on what Akos said (best not to do it). If you really love the idea, look into covering the exterior with sprayed foam and then sprayed concrete.