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dattride

07:15AM | 09/06/04
Member Since: 09/05/04
1 lifetime posts
Bvlawn
I am thinking about building a deck from salt-treated lumber (the newer ACQ not the older CCA stuff). I hear that the newer salt-treated lumber is harder on screws and nails than the old stuff. I want to use screws and am thinking about using either the coated screws or stainless steel screws. I have concern that the coated screws might still corrode either reducing their strength or creating rings of discoloration around the screw.

Any suggestions or experience to guide me?

David

homebild

04:54PM | 09/06/04
Member Since: 01/28/03
693 lifetime posts
ACQ suggests either stainless steel or copper fasteners, or zinc alloy based galvanized steel.

Anything else will cause a di-electric union between two dissimilar metals and and cause the fasteners to fail.

Icemancomth

11:55AM | 09/07/04
Member Since: 06/19/04
23 lifetime posts


If you want some good information on what fasteners to use on ACQ lumber go to this site. It has some info on the fist page and more on the links page too. http://decks.hemmingsjones.com


5slb6

02:40AM | 09/08/04
Member Since: 07/28/02
1356 lifetime posts
From what I have read the stainless steel will be the best followed by double hot dipped galvanized.

Also you can't coat the new wood with just anything because of the copper content. You can use either Flood Seasonite or Wolman Raincoat Oil Based for the first year and then you can coat with something else then if you like.

rpxlpx

10:22AM | 09/13/04
Member Since: 03/13/00
1675 lifetime posts
I've seen a lot of galvanized screws and nails rust completely in two within 10-15 years. I'm convinced that it'w worth the extra cost to get stainless.

Piffin

07:59PM | 09/22/04
Member Since: 11/06/02
1281 lifetime posts
rpx, It only takews a year or two with this new PT lumber. Stainless steel is the only way to be sure.

Excellence is its own reward!


JayF

05:50AM | 09/28/04
Member Since: 11/19/02
59 lifetime posts
Just want to add my two cents in here, as it's been a while since I surfed this board.

I'm with a large east coast treater and have posted on decking topics here previously. As far as this thread goes, there is no salt or precipitate involved with either ACQ (Alkaline Copper Quaternary) or Natural Select (CA-B; Copper Azole) treatment processes. Both processes involve 98% copper (either pure copper or copper oxide) and quat or azole.

Fasteners: For those of you promoting stainless, it comes with a caveat:

If you're using stainless fasteners (screws), you MUST use stainless hangers. Do not mix galvanized or galvanized hot-dipped hangers with stainless fasteners. Just as using inadequate fasteners or hangers with new-generation treated lumber can promote galvanic reaction, the differences between stainless and galvanized materials can do the same thing. Stick to either all stainless or all galvanized hot dipped.

Altereagle

05:47PM | 10/08/04
Member Since: 12/27/02
545 lifetime posts
...hmmm.

Well, first off that wouldn't be the "best site" if you want to know about the new treatments, the best site would be the source:

http://www.treatedwood.com/

( Treatedwood.com is presented by Chemical Specialties Inc. (CSI), a leading supplier of wood protection technology to the wood preservation industry )

or http://www.awpa.com/suppliers/treatedwood.asp

( The American Wood-Preservers’ Association is an international, non-profit, technical society founded in 1904 to provide a common forum for exchange of technical information between industry, research and users of treated wood. )

Several typical waterborne preservatives used in building applications include: Chromated Copper Arsenate (CCA-C), Alkaline Copper Quat (ACQ-C, ACQ-D, ACQ-D Carbonate), Copper Azole (CBA-A & CA-B) and Sodium Borates (SBX).

These treatments are often referred to by trade names such as: Wolmanized Natural Select™ (Copper Azole), Preserve and NatureWood® (ACQ), and Advance Guard® (Borate). Each preservative usually has a number of variations available so care should be exercised when specifying treated wood.

Excellent tip on mixing the fasteners with the hangers... zmax from simpson strong-tie or similar should be used with the new non-arsanate treatments... http://www.strongtie.com/productuse/coatings.html

ANYWAY....

What metals and protective coatings does the Pressure Treated Wood Industry recommend for use with these newer products?

Hot-dipped galvanized or stainless steel fasteners, anchors and hardware are recommended by the Pressure Treated Wood Industry for use with treated wood. This has been the position of this industry for years and their position has not changed with the transition to the alternative copper-based products.

Although their statements do not discuss hot-dipped galvanizing in any detail, it is important to note that the thickness of galvanized coatings varies. The thicker the galvanized coating the longer the expected service life of the fastener, connector, or other hardware will be.

Electroplated / electro galvanized and mechanically galvanized coatings should not be considered to be hot-dip galvanized. (Class 55, or higher, mechanical galvanizing may provide galvanizing equivalent to the hot-dip galvanizing used on connectors and fasteners. Ref. ASTM B695 for additional information.)

It is also worth noting that the galvanized coating thickness varies depending on the galvanizing process used. Remember, the thicker the galvanized coating, the longer the expected service life of the steel will be.

Are all stainless steels acceptable for use with pressure-treated wood?

All stainless steels may not be acceptable for use with pressure treated wood. Testing has shown that Types 304 and 316 stainless steels perform very well with CCA-C, ACQ-C, ACQ-D Carbonate, CBA-A, and CA-B treated woods.

What is hot-dip galvanizing?

Hot-dip galvanizing is a process of providing a protective coating (zinc) over bare steel. The bare steel is cleaned, pickled, fluxed, then dipped in a molten bath of zinc and allowed to cool prior to inspection and shipping. Additional information is available at http://www.galvinfo.com/ . Some anchors and fasteners can be hot-dipped galvanized. Steel connectors can be hot-dipped galvanized.

What is Mechanical Galvanizing?

Mechanical galvanizing is a process of providing a protective coating (zinc) over bare steel. The bare steel is cleaned and loaded into a tumbler containing non-metallic impact beads and zinc dust. As the tumbler is spun, the zinc dust mechanically adheres to the parts. The zinc coating has “good” durability, but has less abrasion resistance than hot-dipped galvanized zinc coatings since it does not metalurgically bond with the steel. Some anchors and fasteners can be mechanically galvanized.

Can I use galvanized fasteners with stainless steel connectors?

No. You should not use galvanized fasteners with stainless steel connectors. Stainless steel fasteners should be used with stainless steel connectors. Galvanizing (zinc) and stainless steel are considered to be dissimilar metals which can cause the zinc to corrode when placed in contact with the stainless steel. This would result in the galvanized fasteners losing their protective coating faster than expected.

Hot-dip galvanized and stainless steel components should not be placed in contact with each other.

http://www.altereagle.com/

http://decks-ca.com

http://kingofcrown.com

Alter Eagle Construction & Design
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