Interiors

Installing Strip Flooring

Nailing Requirements

In general, the wider the wood flooring, the closer the nailing required (Nailing Schedule for Hardwood Strip Flooring, below). Inadequate nailing contributes to cracks and squeaks. Wherever possible, nail into joists.

Minimum nailing:

Strip flooring (under 4 in. wide): nail every 8 to 12 in.

Plank flooring (4 to 8 in. wide): nail no more than every 8 in.

Many installers prefer a closer nailing:

6- and 8-in.-wide planks: nail every 2 to 3 in.

4- to 5-in.-wide planks: nail every 3 to 4 in.

3- to 4-in. flooring: nail every 4 to 6 in.

Standard strip flooring (2 1/4-in.-wide): nail every 6 to 8 in.

Figure: Nailing Schedule for Hardwood Strip Flooring
Flooring Size Size Nail Spacing
3/4-in.-think T&G 2-in. barbed flooring cleat 1 10 to 12 in. apart max.
1 1/2 to 3 1/4 in.-wide strip 7d or 8d flooring nail; or 2-in. 15-ga. staples with 1/2-in. crowns 2 8 to 10 in. preferred
4- to 8-in.wide plank 2-in. barbed flooring cleat 3, 7d or 8d flooring nail, or 2-in. 15-ga. staples with 1/2-in. crowns 4 8 in. apart
1/2-in.-thick T&G
1 1/2- to 2-in.-wide strip		 1 1/2-in. barbed flooring cleat;
5d screw; cut steel, or wire casing nail		 10 in. apart
3/8-in.-thick T&G
1 1/2- to 2-in.-wide strip		 1 1/4-in. barbed flooring cleat;
4d bright wire casing nail		 8 in. apart
5/16-in. Square-Edge 5
1 1/2 and 2 in. wide
1 1/3 in. wide		 1-in. 15-ga. fully barbed flooring brad
1-in. 15-ga. barbed flooring brad		 2 nails every 7 in.
1 nail every 5 in. on alternate sides of strip
Tongue-and-groove flooring should be blind-nailed through the tongue along the length of strips or planks, with nails spaced as shown above. Extend nails within 1 to 3 in. from the ends. Face nails are required on starting runs and finishing runs. Square-edge flooring is face-nailed. Do not mix types of fasteners when blind-nailing the field, except near walls where hand-nailing is required.

Face-nailing plank flooring. In addition to blind-nailing, plank flooring (4 in. and wider) often requires additional fastening with countersunk screws or face nails. Some plank flooring is shipped with countersink holes and plugs. In general, fasten with one or more No. 7 to No. 9 flat-head screws at each end of a plank and at intervals along the length. If the flooring is not predrilled, use the recommended pilot-hole and countersink sizes below.

Figure: Pilot-Hole and Countersink Recommendations
  Hardwood Softwood  
Screw Size Tapered Bit (in.) Straight Bit (in.) Tapered Bit (in.) Straight Bit (in.) Countersink Size (in.)
7 5/32 7/64 9/64 3/32 5/16
8 11/64 1/8 5/32 7/64 3/8
9 3/16 9/64 11/64 1/8 3/8
  Hardwood  
Screw Size Tapered Bit (in.) Straight Bit (in.) Countersink Size (in.)
7 5/32 7/64 5/16
8 11/64 1/8 3/8
9 3/16 9/64 3/8
  Softwood  
Screw Size Tapered Bit (in.) Straight Bit (in.) Countersink Size (in.)
7 9/64 3/32 5/16
8 5/32 7/64 3/8
9 11/64 1/8 3/8

  1. Use 1/2-in. fasteners with 3/4-in. plywood subfloor over a concrete slab. A concrete slab with sleepers 12 in. o.c. does not always require a subfloor. ↩

  2. Use 1/2-in. fasteners with 3/4-in. plywood subfloor over a concrete slab. A concrete slab with sleepers 12 in. o.c. does not always require a subfloor. ↩

  3. Use 1/2-in. fasteners with 3/4-in. plywood subfloor over a concrete slab. A concrete slab with sleepers 12 in. o.c. does not always require a subfloor. ↩

  4. Use 1/2-in. fasteners with 3/4-in. plywood subfloor over a concrete slab. A concrete slab with sleepers 12 in. o.c. does not always require a subfloor. ↩

  5. Not tongue & grooved: Follow manufacturer’s instructions for installing square-edge flooring, which must be installed over a subfloor. ↩