INSTALLATION GUIDE - continued

INSTALLATION OVER WOOD JOIST CONSTRUCTION.

Outside cross ventilation in the foundation walls must be provided through vents or other openings with no dead air areas. A surface cover throughout the crawl space (100%) of 6 mil polyethylene film is essential as a moisture retarder.

Sub-flooring. With 3⁄4" thick strip flooring use either kiln-dried boards of NO. 1 or NO. 2 Common Pine or other dense, Group 1 softwoods suitable for sub-floors over wood joists, or exterior sheathing grade plywood. If plywood, 5⁄8" (19⁄32") or 3⁄4" (23⁄32") performance rated products are preferred. Also, 3⁄4" (23⁄32") OSB is a comparable substrate. With 1⁄2" thick strip flooring use a 3⁄4" (23⁄32") sub-floor. Thinner materials cannot be recommended as a preferred sub-floor material. Install Sub-floor panels as recommended by the panel manufacturer. They should be installed with grain of faces at right angles to joists, nailed every 6” along each joist with appropriate nails and with appropriate spacing at panel ends and edges unless otherwise recommended by the
panel manufacturer. For a board sub floor, use only flat, dry 3⁄4" dressed square edge boards no wider than 6". Lay diagonally
across the joists; allow 1⁄4" to 3⁄8" expansion space between wood boards. Don’t use tongue and groove or side nail boards. Nail to every bearing point (includes blocking) with two 8d common nails. All mitered joints must rest on joists. Mark location of joists so flooring can be nailed into them. Good nailing is important. It keeps the boards rigid, preventing creeping sometimes caused by shrinkage in sub floor lumber. Without adequate nailing it is impossible to obtain solid, non-squeaking floors.

8. LAYING AND FASTENING THE FLOORING

The following instructions apply to strip flooring laid on plywood-on-slab, on screeds, and plywood or board sub-floors.

(NOTE: Flooring “SHORTS” - 11⁄4' or 2' bundles of flooring strips are “Strip Flooring” and should be installed as such.)
NOFMA does not recommend gluing Shorts directly to a slab.

With plywood or board sub floors, start by re-nailing any loose areas and sweeping the sub-floor clean. Mark location of joists on perimeter walls so that starting runs and finishing runs, which require face nailing, can be nailed into joists. Then cover sub floor with a good grade of 15 lb. asphalt felt/building paper, lapped 2"-4" along the edge seams. This helps keep out dust, retards moisture
movement from below, and helps prevent squeaks in dry seasons.
Direction of finish Hardwood flooring. Direction of finish flooring should be at right angles to the joists you can start from left to right or reverse this is most a customer choice from the Oakland hills to the beautiful city of Palo alto floors in California is doing the floor. This is generally the longest dimension of the room or building and gives best appearance. Begin flooring installation along the longest continuous wall parallel to the flooring direction of most rooms. (Down a long hallway wall.) Work from there into the room. Use a slip-tongue to reverse direction and complete the rooms. Glue and blind nail the slip tongue. At any change of direction, always provide tongue and groove engagement either with a slip tongue, or factory edge or end.

Wood joist construction using square-board sub-floors

Starting to lay the floor. Location and straight alignment of the first course is important. Place a mark 3⁄4" plus the width of flooring (3" for 2 1⁄4" flooring) on the end wall near a corner of starting wall. Place similar mark at opposite corner and insert nails into each mark. Pull string line between nails. Nail the first strip with its leading edge on this line.

Starting line to nailing first strip Use of the power nailer for installing strip flooring.

Note: Wood flooring must be installed over a proper sub-floor.