The Facts About Pressure Treated Lumber

Pressure treated lumber is advertised as having aapparent, an inspector might, to be helpful to the
long life (some say 40 plus years) with direct earthclient, say that grading soil back from the lumber, or
contact. The manufacturers soak the lumber inputting it up on a concrete pier, will make it last
chemicals that penetrate into the outside surface.longer. This advice may, or may not, make sense
The most vulnerable area is where the wood is cut.depending on the design elements of the structure,
Any such ends require localized treatment, if they aresay a deck.
to be buried. My experience is that, usually, thisPersonally, as an inspector, here is what I do. If I see
lumber does last a long time. I have some fencepressure treated lumber in a crucial role, and it is in
posts, I put in 20 years ago, that I have since dugcontact with soil, then I call out for grading or
up. All of these were still as good as the day I putremoval of the soil. For example, I call it as a problem
them in the ground. On the other hand, a few times Iwhen I find pressure treated lumber down in soil and
have found pressure treated wood under decks,it is used as a post under the house or on a deck of
even posts resting on piers, where the wood hadany height. In that crucial role, you do not want to
decayed. As with all of life this goes to show thattake chances on rot, the result of wood to earth
there is the design, the plan, the odds andcontact and the moisture that brings to the wood.
sometimes something does not turn out as wasOn the other hand, if I am inspecting a house and
expected. It is out of the "norm".find a couple 4x4's, for support of a handrail, sunk
Pressure treated lumber, and how to deal with it, isinto the earth, at each side of the steps from a
not well defined by the Washington state (where Imodest porch or deck, I check the lumber at the
work) wood destroying organism laws. The wood isground level and, if it is fine, then I do not say very
manufactured for ground contact, so having it touchmuch. No grading is applicable, with the post sunk,
the earth is not specifically a defect. At one point Iand it seems to be holding up well. In my view,
asked the WSDA about this issue and was told thissimple and non-critical outdoor uses, such as fence
-- Fact: Pressure treated wood in contact with theposts, are common and, down the road, the repair is
soil will last much longer if all soil contact is eliminated.easy to do and the area easy to access. The repair
An inspector should probe, if possible, all pressurecan be done by a workman who is affordable and no
treated lumber which has soil contact and, if it isstructural damage is likely to take place.
decayed, then call it out that way. If no decay is