Q. We ordered preprimed HardiePlank lap siding to finish a project, but when it was delivered, we discovered that the backs were left unprimed. Normally, we back-prime wood clapboards, but I’m not sure this step is needed with fiber-cement siding, and the manufacturer’s Web site is mute on the subject. Is back-priming necessary?

A. Mark Parlee, a builder specializing in siding installations in Urbandale, Iowa, replies: You’re right to be concerned about the moisture resistance of fiber-cement siding, but carefully following the manufacturer’s installation guidelines will have more of an impact on the siding’s performance than back-priming. According to Rick Crotts, my...

or Register to read the full article.