Decay Resistance and the Code

Landscaping designs and decking without gaps can drastically affect the drying potential of the framing beneath the deck.

Fascia that wraps the decking in, also traps water against the framing. Decay in these areas is prevalent and is also concealed from view. Until the fascia was pulled out a bit, the owner of this deck had no idea there was a problem, and had just restrained the surface a month prior.

PTI treatment is now recognized and listed in the AWPA standard, and the label for this lumber now provides everything required by the IRC.

Though only a sliver of sap wood can be seen on this face of redwood lumber, it still exceeds ten percent, and therefore is not considered decay resistant.

Bearing “on” concrete vs. “in” concrete makes a difference in whether material must be ground contact rated or not. In this example, placing the lumber in a post base with a standoff would have been a better choice.]

Incising of Douglas Fir lumber helps pressure treatment to penetrate the wood, but is not effective enough to skip the required field treatment of cut ends.

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