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10/25/2005: The EPA mandated that beginning January 1, 2004 CCA (Chromated Copper Arsenate) treated lumber be discontinued for use in residential and other applications. Because of this, most lumber is now being treated with ACQ (Alkaline Copper Quaternary) compounds. ACQ treated lumber contains approxiamately three times the amount of copper as CCA treated lumber, resulting in a product that is five times as corrosive to steel products. How does this affect our industry?

Answer How: The new ACQ componds will corrode and deterioate flooring nails and subfloor fastners within 3-5 years! This will result in failure in the floor systems.

Solution: Source NOFMA Installation Guide

1: Use stainless steel nails and attatch your subfloor as follows:

This system uses as a nailing base flat, dry 2" x 4" screeds of Group 1 density wood (sometimes called sleepers) of random lengths from 18" to 48", as a nailing base. They must be preservative treated with a product suitable for interior installation. After treatment screeds must be dried to a Moisture Content of 12% or less, if saturation with water is involved.

Screeds are laid on their flat face in rivers of mastic with screed runs 12" on center at right angles to the direction of the finished floor.

Sweep the slab clean, prime with an* asphalt primer and allow to dry. Apply hot (poured) or cold (cut-back) asphalt mastic and imbed the screeds. Stagger joints and lap ends at least 4" and leave 1/2" space between lapped edges. Be sure there is enough mastic for 100% contact between screeds and slab. Leave 3/4" space between ends of screeds and walls with a continuous run of screeds at end walls.

Over the screeds lay a 4- to 6-mil polyethylene vapor retarder with edges lapped over rows of screeds. Avoid bunching or puncturing it, especially between screeds. The finish flooring will be nailed to the screeds through the film.

The system with screeds spaced 12" on center and a moisture retarder without a subfloor is satisfactory for all 3/4" Strip Flooring and Plank Flooring less than 4" wide. Plank Flooring 4" and wider requires either the Plywood On-Slab subfloor, or screeds plus a wood subfloor, to provide an adequate nailing surface. The subfloor over screeds may be 5/8" or thicker plywood, 3/4" OSB (performance rated), or 3/4" Group 1 dense softwood boards or equivalent no wider than 6". If subfloor boards are used over sleepers or screeds, allow 1/2" spacing between boards.

NOTE: When area moisture conditions are considered high (Gulf coastal area) use the vapor retarder glued directly to the slab system in addition to or in substitution for the film draped over screeds.


2: Put your vapor barrier directly to the slab. Then you can use untreated 2" x 4" lumber. Do not drape visqueen on top the screeds. Note: screed system must be out of 2" x 4" lumber not 1" x 4" or 6" lumber. Then you can use tradition steel flooring nails or staples.