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2018 National Home Improvement Estimator, All Rights Reserved Page 445

Chapter 16, Porches and Decks

Adding a porch or a deck is a popular home improvement project. The advantage is obvious. Porches
and decks add value at a lesser square foot cost than similar enclosed living area. What isn't so obvious
is the disadvantage: porches and decks are more exposed to the weather and have a life expectancy
considerably less than the home itself. That makes porch and deck work a common repair task. The
result is a steady volume of work for porch and deck specialists. This chapter includes cost estimates
for both the addition of new porches and decks, and repair work.

Inspecting for Decay
Exposure to sun, wind and rain tends to open wood grain. The result is a higher moisture content which
supports the growth of wood-destroying organisms. Nearly all wood decays if it remains moist for long
periods. Check for decay and insect damage with a screwdriver. Wood has lost nearly all its
load-carrying capacity when you can push a common screwdriver blade into the grain. Deck flooring
needs to be replaced when it sags under foot traffic.

Check the crawl space under the porch or deck for signs of dampness. Condensation forms on the
underside of an elevated porch or deck when there isn't proper ventilation. Replace decayed framing with
treated lumber.
Give particular attention to posts that are in contact with concrete. Posts should be replaced when
heavily decayed. Support the new post slightly above the porch floor with a post anchor, as in Figure
16-1. Embed the post anchor in concrete to help protect the porch roof from uplift wind forces.

If a decayed post is strictly ornamental, consider cutting off the decayed base. Replace the decayed
portion with a wood block secured to the concrete with a pin and a washer. Add base trim to conceal
the patch (see Figure 16-2). Keep trim pieces slightly above the concrete so moisture can escape.