On Thu, 17 Sep 2015 15:48:26 -0700, "Bob F"
wrote:

Mayayana wrote:
Mayayana wrote:
At 20 years old, it is probably the old PT wood, not the current
stuff. Required fasteners are different.


It is the old stuff. So I have resistant arsenic
instead of whatever it is they're using now. (To
this day I haven't been able to find out what the
new "acq" is made of.)

But that doesn't have anything to do with nails
and screws.

Really?

The high level of copper in lumber treated with ACQ or CA speeds up
the corrosion of most fasteners, so for decks or other outdoor
projects made from pressure-treated lumber, code requires the use of
fasteners that offer good corrosion resistance.


They both have copper. You said the required
fasteners are different for each. I've used mostly
plain galvanized nails with both and never seen
a problem.

Good galvanized nails are one of the recommended possibilities.

Good meaning "hot dipped", not plated. Rough, nasty, scaly finish is
the halmark of the hot dipped fastener. Sometimes they are bonded
together by the zink when you buy them - -