Treated Lumber Changes

Here is something to watch out for when inspecting structures built with
treated wood. A couple years ago the industry went through some
changes in the chemicals that wood is treated with. Now we have
several factors that came out of that change that could affect a
home inspector.

  • Lumber yards now carry treated lumber and tell people its “just about
    the same as the old stuff”… but that is not always true. Much of the
    “old stuff” was treated for “ground contact” and you could use it for a
    lot of things that touched the ground. But NOW… many of the same
    cuts of lumber are treated for “above ground” use only (and they still
    look the same as the old stuff). Many builders still use the new stuff,
    that has less treatment, and it will not endure the ground contact like
    the old stuff.

I just saw a cedar fence built around a house and a nice new wooden
porch built on the back of the house. Much of the frame work on the
fence and porch was treated yellow pipe. The local lumber yards only
carry “above ground” lumber in these cuts of lumber (2x4, 2x6, 2x8, 2x10
and 2x12)… and I know the local builders just keep pushing that wood
into the ground when they need to. But its not gonna work like it used
to. The treatment has changed but the habits of the builders have not!

* Above Ground - 0.25 - Decking, fence boards, hand rails, deck supports
* Ground Contact Fresh Water - 0.40 - Fences, landscaping, piers, docks
* Permanent Wood Foundations - 0.60 - Wood foundations, crawl spaces
* Poles - 0.60 - Building, transmission and distribution poles

Notice that 0.60 is for “Wood Foundations”…(most lumber yards here do not
carry 0.60 unless it is special ordered. And some cuts cannot be treated to
that level unless they are classified for “bridge construction” and even then
the smaller lumber is not allowed to be treated to 0.60)

So then… do builders in your area go to the trouble to meet these
requirements? Or… are they still banking on the fact that no one
can see any difference in the appearance of the treated lumber…
because they all look the same? Hmmm.

To see a some more info about this look at:

We have a problem when we inspect it…

Our problem is this… We cannot tell if the treatment levels are for
“above ground” or “below ground”. So when in doubt… make note of
this on your report so the Customer can try to verify what he is
actually getting, and you can protect yourself from a future problem
with decayed lumber in the ground around someones house.

I wrote the condition as “conducive to termites” also, because the wood
fence frame (treated yellow pine) was touching the slab and house…
just like those old nasty garden ties that people put around their flower
beds to feed the termites. (smile) The treatment slows em down but it
does not last that long sometimes.

The larger cuts of lumber (4x4, 4x6, 6x6) seem to have a higher treatment
level at our local lumber yard because it is common for these kinds of
cuts to go into the ground and are less likely to be used where humans
will walk on them with their bare feet. (this is the reason the EPA wanted
less treatment in the lumber that people come in contact with more often).

So… certain kinds of cuts touching the ground are a red flag around here.
Other kinds of larger cuts are less of a flag but if they are used in
the construction of a Foundation… they need to be verified (because
local lumber yards do not always carry 0.60 treated lumber that is
required for Foundations).

Something to think about.

What I have also seen with treated lumber is that builders do not instruct their men on which side of a 4x4 or 6x6 should go into the ground. I have gone to many a job site where the post were rotting and may have been only 8years old. Why, because the preservative gets sucked up through the end grain more efficiently then it gets absorbed through the sides. Without that knowledge, carpenters are cutting the post to fit but are putting the cut end down on the pad or in the ground where there is the least amount of preservative , which in turns decays much faster.

Also keep an eye on the fasteners and flashings as the new wood can cause galvanic reactions.