Spray foam sounds like a mess in the making and unnecessary IMO. Getting it rigid should not be an issue if built from lumber and done correctly. I frame my walls like a house and thus mine are build like a tank and very comfortable inside and appear to last more than 20 years in their final resting places. In fact I can re-do mine they are not rotten. Possibly get another 10 years from them with new plywood.


Do it right and they are a long-term investment. Cobble it together with scraps and you'll be working on repairs or replacement in short order. That's my experience. I have even used real siding on them. The main thing you don't want is anywhere bugs or critters can get behind a wall or joint that's something to mention and watch out for.

Otherwise there are plenty of videos on YouTube that show how to correctly frame and build a project like this. Not cheap but neither is replacing them. And they are still much cheaper to build than purchasing something like a Muddy or Redneck Blind.

Sportsman Condo - I like and cost effective but exactly like being in a big garbage can. Love it or hate it that's the only comparable option that's realistic in terms of longevity.