I should have specified when I said a "lean to" I meant a freestanding structure open at the front with a single pitch roof caused by building the front side higher than the rear. I have no intention of butting this thing up against my house. Thanks

I use the terms interchangeably because I'm a rookie/frequently wrong but yes, I'll be using treated lumber for the structure.

Thanks!

Ding ding ding, I have no idea why that didn't occur to me ahead of time. Glad I asked.