I use grass clippings all year and stockpile straw, leaves, etc for wintertime. Free litter for 7 months of year. I do have a linoleum floor over 3/4 OSB. I also ran strips of linoleum up the sides of the 4 walls between the studs and it laps out over the base plate of the wall frame to prevent poop buildup and subsequent odor. Should be easy to just hose out when I change the litter. I did caulk it along the sides and top so that water would not get behind if if I do hose it off. Have seen no poop there yet tho. The way I did it tho, they cannot stand on the wall base plate because the strips come down at a steep angle from the outer sheathing. Nowhere for them to stand. I am going to use leaves all winter until I run out, then I will switch to straw. I want to buy as little as possible and use all the free stuff that I have here first. I have not done poop planks but am considering them. Would like to make them with linoleum tops for easy scraping/cleaning.