Lesson 3.2 Subflooring

1-12. Plywood Subflooring.

After the foundation and basic framework for the floor are completed, the subfloor can be installed. Material for constructing the subfloor can be either 1-inch or 2-inch material. Plywood is very satisfactory for subflooring because of the large sheets which can be installed rapidly. The thicknesses required are 1/2-, 5/8-, or 3/4-inch, depending on the joist spacing and the floor load requirement.

1. Lay sheets with the face grain at a right angle to the joist when installing plywood.
2. Lay the sheets so that the joists are placed over the joists.
3. Arrange plywood so that the joints for the complete floor are staggered (see Figure 1-24 ).
4. Glue and nail the plywood in place.

Figure 1-24. Plywood subflooring

1-13. Diagonal Subflooring.

Lay diagonal subflooring on the joist framework and nail it in place (See Figure 1-25 ). Subfloor material can be either 1-inch or 2-inch material.

1. Lay the subfloor before the walls are framed.
2. Square the ends of the boards before nailing when laying the flooring.
3. Place the ends of the boards before nailing when laying the flooring.
4. Use at least three nails per joist for boards 8 inches wide or more.

Figure 1-25. Diagonal subflooring