Some clients have recently instructed us to remove all preservative treated wood as it presumably causes corrosion of all associated galvanized products, not only fasteners in the wood member. I read previous thread that pertains mostly to fasteners and the May 05 Construction Specifier article which recommends hot dip galvanizing and stainless steel fasteners in certain applications.
Is there any information that recommends eliminating pressure preservative treated entirely due to problems with corrosion (not just fasteners)or recommends methods to avoid this corrosion?
Be careful about a blanket elimination of preservative-treated wood. Most building codes (IBC and UBC) have specific instances where preservative-treated wood (or naturally durable wood) is required.
Oh, and if you’re wondering, naturally durable wood is traditionally considered any of the North American Cedars (Western Red, Eastern White, and Yellow) and, of course, Redwood.
Ken-
our here in the soggy west, the issues with preservative treated wood and fasteners comes up repeatedly, and the answer seems to be hot dipped galvanized or stainless fasteners. I also recommend using nice little flat neoprene washers in some cases as well. you will nearly always get a substitute for the stainless steel or hot-dipped, but don’t take the substitutuions. And yes, in our area, the code does require all ground contact wood be preservative treated and removing it is not an option.
Maze Nails produces a product by the trade of STROMGUARD. They produce a wide variety of fasteners (nails and screws).
For borate pressure-preservative treated furring I specify fasteners with double hot-dip zinc coating complying with ASTM A 153 (minimum coating G185) same as Maze Nail STORMGUARD, or Type 304 stainless steel.
For ACQ or similar pressure-preservative treated furring: Type 304 stainless steel.
My region is the same as Annes’.
Fastener providers such Simpson Strong-Tie have developed strategies for protecting their hot-dipped galvanized products. Grace Contruction Products have products and installation instructions for protecting and isolating fasteners from preservative treated lumber.
Thorough specifications and detailing are required to document the design intent otherwise the GC will select the option.
Ken Crocco
The corrosion problem extends to steel; galvanized, less than G185; and aluminum.
Treated wood nailers in roofing systems cause a proble for metal roof deck, coping; gravel stops; flashing; curtain walls.
Carlisle recommend not using it in conjunction with their roof system. If used, lap their membrane over coping or provide a separation sheet(slip sheet)between wood and aluminum and metal items.
Contact your local Carlisle rep for tech data bulliten at martyg@comroofs.com
On Jan 16, 07 Norther IL CSI Chapters “Specification Roundtable” will discuss this topic, it’s by teleconference so if you want to join us, let me know and I will email you phone no. and access code.