Thank you Noah.
I lay the all the walls face down after mapping out, planning and executing any modifications to the original walls (generally changes in door or window location or size).
I picked up a baggie (probably a couple of hundred pieces or more) of some type of basswood square sticks at a JoAnn's Fabric (Like a Michael's) store that are probably each 3" long and measure out to a scale 12x12. Prior to getting these, I used the more expensive strips from Kappler or Northeastern.
I cut, fit and glue these to the inside walls, both horizontally and vertically, avoiding window, door or slot openings. It doesn't need to be done with any precision just make sure you test fit walls together to make certain you don't glue a brace somewhere that inhibits construction.
I try to plan ahead and use some near the edges of adjoining walls and roof edges to allow for a larger gluing surface. The goal is simply to make a sturdy wall that won't curl or bow.
I tend to use a lot of craft acrylic paints on laser structures and these paints combined with the water needed to thin them can cause these issues if precautions aren't taken.
The shingles I used in this case were produced by Rusty Stumps.
https://www.rustystumps.com/products.asp?cat=49Let me know if you have other questions and good luck.
