I’m on a budget but planning on building a 5x5 for myself and a 5x6 for a 2 person. I’m going to use treated lumber for my frame but can I use untreated studs for everything inside? Wanting these both to be on 6’ wooden platforms as I don’t have a welding machine. What siding do y’all recommend?

I use 5/16" outdoor plywood and paint it. The blind pictured is 6 years old.

Use fiber cement board and be done.

yep pay once and be done

I've used treated lumber for the base, then untreated 2x2 for the uprights and rest of the frame. Then I skin using SmartSide composite siding. Then regular ply wood for the floor and roof, then cover the roof with corrugated sheet metal with at least 6" overhang on all sides to provide a drip ledge.

just keep in mind the more you add, the more the weight. My first build, a 4x4x7, I did in my garage built to last including a shingled roof ... and like to never got it loaded/unloaded due to weight. Thankfully, I now have a FEL on my tractor

USMC, Several good ideas but here are some negatives. Cement board= HEAVY & TUFF TO CUT. Other types of outside siding are also very heavy. I have not priced either but assume they are expensive. OSB is cheap but do not use it on a horizonal surface (floors), with a good paint job OSB will last SEVERAL YEARS IN A VERTICAL POSITION (walls). You can also use shingles on the walls & most roofing companies will have a pile of un-used that can be bought cheap. They don't have to match to give great protection to the wooden structure. Shingles can be put on after you get the blind in place to keep weight down during actual moving. Hope you find out what works for you. Daniel

Treated lumber for a 6' platform is great. Just cross brace and anchor. My builds for interior framing are 2x2 untreated, same with roof..2X2 join at corners to essentially make 2X4. Use exterior grade plywood. OSB will gather moisture on seams even if painted/caulked well. Buy 3/8" plywood for walls and 1/4" for roof. For the roof I jut put a thick coat of RV rubber seal on along with some drip edge metal. Roof should be extended 6" on all sides

Good advice right here.

I had Mueller’s cut me 5’ sheet flat sheet metal. They are 42” wide so you can ship lap to get the desired height. Works well for a 5x5 with no cutting. Just screw them on and use a cutting wheel for a grinder for windows. Much cheaper than plywood and get them in any color you want. No waste. Used regular R panel for the top. Less than 3$ per foot.

Mine built like this lasted 23 years before the base started to rot, cannot remember if I used treated for the base or not. I used sheet metal for the roof.

I built something similar, OP, pics of mine are in this thread: https://texashuntingforum.com/forum/ubbthreads.php/topics/7627243/window-openings#Post7627243

I used treated 2x6 for the base, which is 48x83" (I didn't want to use more than one sheet of plywood on the ends). Most of interior 2x boards are reclaimed lumber from demolition jobs. One thing to do before you build, measure the trailer you want to haul on. My 5'x10' trailer is actually 58" inside the rails. If I'd gone 5' I'd have been in trouble. Also, for anyone putting on an extended roof, I followed a guy moving one on HWY84 one day. Tin tends to come flying off in a hurry at 70+mph when the winds gets under the overhang..

I used 2x6 treated lumber for the base, then a sheet of 3/4” plywood for the floor, and some untreated 2x2s for the framing. We then skinned it with some smart siding and thin sheet of plywood I had laying around for the roof. Also added some tin for the roof for longer protection. For the legs I used some elevator brackets from Academy, treated 4x4s and just some 2x4 cross bracing. I’ve sat in it with some pretty stout winds and it hasn’t budged one bit.

Pretty much what I did as well. I used 2 come alongs and 3/8" logging chain to hoist that bad boy 12' up on the air. I painted the plywood with 3 thick coats before I installed.