1. Lumber shall be southern pine, grade #2 or better and shall be ACQ, CA-B or CuN-W pressure treated. Lumber in contact with the ground shall be rated as “ground-contact.” Please note: not all treated lumber is rated for ground contact.
2. Wood-plastic composites are composed of bound wood and plastic fibers creating material that can be used as decking and guard elements as permitted herein. Permissible wood-plastic composites must bear a label indicating its performance criteria and compliance with ASTM D 7032.
3. Nails shall be ring-shanked or annular grooved. 4. Screws and nails shall be hot-dipped galvanized, stainless steel or approved for use with pressure treated lumber.
5. Hardware, e.g., joist hangers, cast-in-place post anchors, and mechanical fasteners, shall be galvanized with 1.85 oz/sf of zinc (G-185 coating) or shall be stainless steel. Use products such as “Zmax” from Simpson Strong-Tie or “Triple Zinc” and “Gold Coat” from USP.
6. Decks greater than 20 sf shall have an electrical outlet along the perimeter of the deck and within 6′-6″ of the surface.
7. Decks constructed in accordance with these details are not approved for privacy screens, planters, built-in seating or hot tub installations.
8. Information regarding permit, plan review and inspection requirements can be found in the “Decks” publication at alexandriava.gov/code.
9. Publication DCA6 by the American Wood Council is considered equivalent to these details and can be used to obtain a permit in the City of Alexandria. Go to awc.org to learn more and to download the publication.
Wood and wood-plastic composite decking shall be installed in accordance with the requirements below.
1. Dimensions shall be 2×6 or 5/4 (“fivequarter”) for wood and per manufacturer for wood-plastic composites.
2. Wood decking may be placed at an angle of 45 to 90 degrees to the joists.
3. Attach wood decking in accordance with FIGURE 1.
4. Placement and attachment of wood-plastic composites shall be per manufacturer’s instructions.
5. Wood-plastic composite label and manufacturer’s instructions must be left on the jobsite for inspector verification.
Plastic or PVC decking, not considered a wood-plastic composite, may be substituted only when the product has a valid evaluation report from an accredited listing agency and is capable of resisting a live load of 40 PSF. Installation shall be in conformance to the evaluation report and the manufacturer’s installation instructions which must be available to the inspector.