With Maya off to college, Kyle has stepped in to partner with me for the remainder of the tiny house build. He too is interested in learning the construction skills needed to build a house. We started today with interior walls. Normal homes use gypsum board (sheetrock) with joint compound to hide seams.  The racking forces on the frame of a trailer during towing would almost certainly produce cracks in such joints over time. We are using 1/2″ thick MDO plywood with flexible caulking between them. To hide the seams we rout vertical V-grooves on 8″ centers and half a V at the edges of each panel. Seams will appear the same as the other grooves. When painted this will look like wide tongue and groove boards. Preparing each 4’x8′ panel is very time-consuming and requires a precise layout for windows, outlets, switches other such features followed by the routing operations to create the grooves. It takes us about 2 hours per panel so this phase of the build is going to proceed slowly, especially in light of the fact that we plan to only work half days.