The primary difference between Rmax and Thermax is that Rmax is not as strong
as
Thermax. I built a window box solar air heater last December. The plans
called
for Thermax. In discussions at a solar heater group at Yahoogroups, the
general
consensus was that Rmax was OK as a substitute,
I built a stretch hexayurt and beveled all the edges where the panels met.
I think beveling is critical to the strength of the walls and also improves
the R value of the walls. Beveling is really not as difficult as some
imagine. I just placed a few 2x4s on a level surface, snapped a chalk line
