It’s been a while but I’m back and going to take the time today to explain my favorite detail design of my tiny house: the wall construction. To give my house more character I designed my wall framing to have an exterior a bump out. I have to start by giving a shout out to the managing principal at Bergland and Cram, Scott Smed, aka my boss. He really helped me through detailing the components of the wall construction and made my vision a reality. So thanks Smed, I really appreciate all your help if you ever read this!
Most typical new residential construction uses 2×6 studs for the wall framing. Since every inch counts for a tiny home, my house was built with 2×4 framing to allow more floor square footage. My house wall framing was done in three layers using 2×4 lumber. These three layers were typical framing, horizontal cleats, and secondary wall framing.
This first layer of framing is a typical residential framing. The window and door headers are in this layer as it is the load bearing framing to hold the weight of the roof and the loft framing. The shell of the house is basically a space frame that the loft framing will be anchored to. The roof rafters will be set on top of each stud to have a direct transfer of load down to the floor joists.
Call it what you want, but I am considering the horizontal members running across the first layer of framing horizontal cleats. These cleats start to create the shape of the bump out. Their layout is based off a cleat being at the top and base plate of the first layer of framing. The cleats are then dispersed two feet on center while creating the boundary of the bump out and outlining the windows in the loft.
This layer is really when the wrap house takes its shape. This is just another layer of wall framing where everything comes together structurally. This layer of structure is connected to the cleats and creates the whole detail.
Here we have a total roof-to-window detail of the wall bump out. You can see the window header under the double top plate. The very top layer of the wall lumber is a 2×10 ripped down to the total wall thickness that ties all three layers of framing together. You can see how the horizontal cleats are on the head and sill of the window along with the second layer of framing. The birdsmouth roof rafters lie on that top plate with a 2×6 fascia board. That makes the bump out have a flat surface without a roof soffit. Next you wrap everything in sheathing and tyvek and you’re ready to roll for exterior material finishes.
There have been quite a few pros compared to cons with this construction style. First, the structure of the wrap house is sturdier with this extra application to create lateral stability. Second, the bump out area houses all my plumbing with the secondary structure being filled with insulation and the interior wall holding the water lines. With a 2×6 wall construction you have a lot more room for insulation and plumbing in walls. This bump out allows me to get that benefit without losing floor space. Third, I created uniqueness to my project that I wanted to accomplish. The one large con from doing this construction is it costs much more to have double the lumber to create a desired look.
This is a technical post so feel free to ask questions if there’s something you don’t quite follow or want more information on these unique details. This design has worked wonderfully for my vision to turn my box into an interesting piece of contemporary architecture.