On Fri, 26 May 2017 21:03:38 -0400, wrote:

On Fri, 26 May 2017 20:01:42 -0400, wrote:

On Fri, 26 May 2017 16:18:34 -0400, Ed Pawlowski wrote:

I don't know about sheds, but some fasteners will corrode from ACQ or CA
treated wood. They are, of course, in direct contact. Perhaps a
barrier of some sort is all you need.

I am really starting to question the concern. I am 3 1/2 years into a
science fair project where I put CaC out in the weather with an
assortment of metals and fasteners. So far I having no signs of
external problems. I will be taking it apart at the 5 year mark to see
what I have.
http://gfretwell.com/ftp/PT%20lumber...2010-25-13.jpg
This is a Florida southern exposure to full weather.
The new ACQ is worse than the old stuff. There are
ceramic coated" deck fasteners that seam to wotk well - otherwize hot
dip galvanized or stainless are highly recommended. A friend's garage
had aluminum cladding in contact with ACQ lumber and it corroded right
through within 3 years. The steel hardware of the garage door is
severely compromized about 7? years after install. The same hardware
on standard SPF lumber is in good shape after 43 years (the house was
8 years old when I bought it 25 years ago)

ACQ is really not around that much these days. CaC seems to be the PT
of choice for the upland crowd. I live close enough to salt water that
I can still get CCA. 0,6 or 0.8 is going to last for decades if it is
not submerged and 2.5 CCA will do 30+ years in tropical salt water if
you wrap it. That is more like 50 years in direct burial, upland.