Crap PT here. At farm, I treat exposed lumber. Summertime. Narrow wood frame, longest length, plus 1 ft. Level! 6 mil poly folded. Staple top. Saw horses above, and beside over poly. Drip in trough. Dry for day or 2. Old or cheap new motor oil, 50/50 with diesel. Dip one board for a minute, rotating, further dry rotating. Saturate cut end or drill hole. Lasts many times longer than so called PT, and better eco.