While recovering from the flu I found myself obsessing more and more about this ultralight house concept. I also began researching other unrelated ultralight topics like ultralight backpacking. I guess seeking extreme examples of less is more is just a fun to noodle over; but I have to admit… I think I’m developing a bit of an obsession for ultralight design. It could be a temporary condition though… I’ll keep you posted.
The last design proved that for a tiny house to be truly ultralight it must be built more like a travel trailer than a house. The disadvantage of this approach is that as the walls get thinner and lighter the house becomes less suitable for 4-season living. It also gets a bit harder to build with easily obtained and inexpensive building materials.
You could use aluminum, titanium, carbon fiber, and other composite materials but that tiny house might cost a fortune. Since I’d rather present ideas that are low cost and easy to implement I chose to stick with common building materials for this version.
Imagine a wall system that starts out as a 2×4 and 2×2 frame. To that is glued and screwed an exterior layer of 1/2 plywood or OSB (oriented strand board). To lighten that heavy layer of plywood big sections would be cut out, but in such a fashion that retains much of the strength. Then a 1 1/2″ foam board (R-9) is glued into the cavities. To seal the interior side of the wall a thin layer of wall paneling is glued and nailed into place. The total wall would be just over 2-inches thick and have an insulation value of about R-10. Additional reflective layers of insulation could also be added as well as layers or house wrap to help seal up the walls. The exterior would be covered with lightweight metal roofing panels, like standing seam roofing or corrugated panels.
The floor would be as thin as the walls since the trailer provides a firm flat platform. The roof would be a bit thicker with a full 3 1/2″ space for insulation. The trailer would still measure 6′ by 10′ making the interior floor space about 55 square feet. What I’m not sure about is if this approach would really be strong enough to hold up to regular highway travel. I bet with the addition of metal bracing (hurricane/earthquake straps) it would do fine but I’m not an engineer so I can’t be sure.
I also want to thank all the folks that provided all the links to cool trailers and suggestions for making the house lighter. I was really blown away by all the great ideas that the original design concept elicited from our wider community. I’m going to try to step back from my growing lightweight obsession for a moment now and finish the 12×24 plans. I know there are a lot of people waiting for those plans.