 What has
occurred?
In 2002, the EPA announced a voluntary decision by the treated wood industry to
move consumer and residential use of treated lumber products away from pressure
treated wood that contains arsenic (CCA) by December 31, 2003, in favor of new
alternative wood preservatives.
What are the
New Wood Preservatives?
The predominant alternative preservative is Alkaline Copper Quat or ACQ. ACQ
treated wood provides long term protection from rot, decay, and termites without
the use of arsenic, chromium or other EPA classified hazardous chemicals. The
main active ingredient in ACQ is copper, which is a proven cost effective
component that protects against decay and insects. Quat provides additional
protection from fungi and insects that copper cannot control. Quat is commonly
found in household cleaners and disinfectants. Chemical Specialties, Inc., the
maker of ACQ, markets ACQ under the Preserve and Preserve Plus brand names. ACQ
is currently the dominant new alternative wood treatment, there are other
companies that have developed similar alternative treatments as well such as:
Osmose NatureWood (ACQ), Wolmanized Natural Select (Copper Azole), and Osmose
Advanced Guard (Borate).
Is ACQ more
corrosive to fasteners than CCA?
Chemical Specialties Inc. (CSI) admits that ACQ is somewhat more corrosive to
fasteners than CCA. To what extent? It depends on the wood retention level, the
environment, and the fastener coating or material used. There are some fastener
coatings, found through testing by CSI, that do not perform well when in contact
with ACQ lumber. They are Electro Galvanized (referred to as Zinc Plated on
Hillman screws), Zinc & Yellow Dichromate (used on Hillman All Purpose Wood
Screws), and Dacrotized coatings (not used by Hillman). Hillman recommends that
Zinc Plated and Zinc & Yellow Dichromate Plated fasteners be used for interior
applications only. Hillman Zinc Plated fasteners and Zinc & Yellow Dichromate
fasteners are NOT recommended for outdoor applications or for use in treated
lumber.
What
fasteners are recommended for ACQ, CA, CBA, SBX, ACZA, and CCA treated
woods?
BEST Recommendations
•Hillman Power Pro Stainless Steel Outdoor Screws
•Hillman Power Pro Stainless Steel Trim Screws
•Hillman Project Center Stainless Steel Deck Screws
•Hillman Project Center Stainless Steel Trim Screws
•Hillman Stainless Steel Carriage Bolts, Lag Screws, Hex Nuts and Washers
BETTER Recommendations
•Hillman Power Pro Outdoor Screws – Ceramic Coated
•Hillman Power Pro Trim Screws – Ceramic Coated
•Hillman Power Pro Construction Lag Screws – Ceramic Coated
•Hillman Project Center Deck Plus Screws – Ceramic Coated
•Hillman Project Center Self Piercing Sheeter Screws (aka polebarn screws) –
Ceramic Coated
•Rawl Tapper Concrete Screw Anchors – Blue Permaseal Coated
GOOD Recommendations
•Hillman Project Center Mechanical Galvanized Deck Screws (ASTM B695, Class
50, Type II)
•Hillman Hot Dipped Galvanized Carriage Bolts, Lag Screws, Hex Nuts and
Washers (ASTM A153, Class C & D)
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 The Treated Wood Industry
recommends the use of Hot Dipped Galvanized or Stainless Steel
fasteners. These are the same recommendations given for CCA lumber and
have been the position of the Treated Wood Industry for years. There is
a middle area between Hot Dipped Galvanized and Stainless fasteners
where the newer, state-of-the-art, epoxy and ceramic coated screws fit
into.
Chemical Specialties Inc., the maker of the ACQ
treatment states, “the primary fastener systems for use with Preserve treated
wood (ACQ) are Hot Dipped Galvanized and Stainless Steel.” CSI's testing results
from standard accelerated corrosion tests for ACQ treated wood are similar to
CCA treated wood with Hot Dipped Galvanized fasteners. Arch Wood Protection, the
maker of Copper Azole, states “the effect of Copper Azole wood on fasteners is
similar to that of CCA treated wood.”
One important point to emphasize is that all
plated metals may experience corrosion over a period of time. Stainless steel is
the only fastener material available that will prevent corrosion in most
applications.
Please work with your Hillman sales
representative to make sure you have the proper Hillman fasteners in your
display to adequately deal with the new treated lumber. Hillman will continue to
test and inspect our exterior fasteners to ensure they perform efficiently.
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