How to treat PT wood

First you must decide for how many years you want to maintain the appearance of the wood. We know that wood in contact with ordinary damp earth will develop rot and cracks in anything from 2 to 20 years, depending on local conditions.

That's a pretty tough one, and depending on where you are, can be almost impossible. They pump in a boatload of chemicals, along with a lot of water, under pressure, and the wood is usually Southern Yellow Pine. PT wood tends to shrink and check a lot. To prevent checking you have to keep the wood from releasing its moisture content. If you're in an arid area, it will start checking quickly.

You could try to seal the exposed surface with something - basically any deck sealant, but that's not a guaranty.

You've built in maintenance where there should be none. I would have buried a piece of Trex, or approved equivalent, which would look pretty much the same for years/decades.

I've put a deck stain on deck, stairs to bottom of back yard, and rail fence made of PT wood. Looks much better that the yucky green of aged PT wood.

"Aaron Fude" wrote

Hi Aaron, common here in my area. There's several ways to deal with it to make it last longer. Deck wash 'stuff' (Thompson's water deck seal isnt very good but you know the type of product). That goes a long way. The clear stuff can be applied every year pretty easy with a mop (grin).

No matter what, it will eventualy need boards replaced. They wont fail evenly either so most here have a bit of a patchwork look of new and old. Built 'right' it's easy to replace a board or two. Usually about 5 year point for here, you start to replace a few evey year. If you did it like we do here, you can replace 5 or 6 boards in about 2 hours time (less if you are used to such and have good tools).