Do-It-Yourself Replacement of an Exterior Porch Floor

Tear-Off

• The old porch floor must be removed before you can install the new decking. If the boards were screwed down and you can see the screw heads, a screw gun, set to “Reverse,” is the quickest way to remove the old screws. Some porches have layers of old paint, however, making it difficult to remove the individual screws. In this case, or if the decking is attached with nails, you’ll need a flat bar or a crow bar to pry the boards from the joists beneath. Remove the boards from the steps as well, and pull remaining nails with a nail bar.

Repair and Prep

• For the new floor to look its best, the joists beneath the porch floor should be in good shape. If some of the joists are rotted or show signs of termite damage, this is the time to replace them. If you remove a damaged joist, replace it with a joist of the same dimensions and attach it in the same spot. Reinforce old joists that are loose or wobbly by inserting one or two wood screws or nails through the rim joist and into the ends of the joists. The rim joist is the board that forms the outside frame of the porch and holds the joists in place.

Decking Choices

• You can choose from many types of weather-resistant decking boards on the market today. If you want real wood, install cedar, redwood or treated wood, all of which resist damage from moisture. Composite decking boards, manufactured from compressed wood fibers and resin, resemble wood but are much more durable. Standard decking boards are at least 3/4 inch thick, and installation requires the insertion of two screws, evenly spaced, through the boards and into every joist. For restoring historic homes with painted wood porches, tongue-and-groove fir is available, but it’s more expensive than standard decking boards or composite decking.

Considerations

• Redwood, cedar and treated wood decking expand when wet, so install the boards with a 1/8-inch gap in between each board to allow for swelling. Composite decking will not swell, but depending upon the look you want, you can leave a small gap between the boards. Tongue-and-groove fir must be sealed and painted with a good-quality exterior porch enamel to reduce the risk of expansion and buckling. Redwood and cedar benefit from an application of wood sealer once or twice a year.