ASK This Old House | Weird Shower Valve, Mossy Roof (S18 E14) FULL EPISODE

Summary by Krater

Experts from Ask This Old House visit homeowners to inspect a leaking shower valve and a moss-covered roof. They determine that both problems stem from unique legacy building materials from the 1940s—an obsolete 1940s galvanized steel shower valve and a moss-covered asphalt shingle roof—and replace the old shower valve with a modern single-lever pressure-balanced valve and clean and seal the roof.

From the video

Answers: How do you replace an old two-valve shower plumbing system and clean moss off a roof?

• Plumbing repair
• Shower valve replacement
• Roof maintenance
• Moss removal on roofs
• Galvanized steel pipe replacement
• Home renovation

What it concludes

• A 1940s two-valve shower faucet can be replaced without replacing the surrounding fiberglass wall by using a modern pressure-balanced valve and access panel behind the wall.
• Galvanized steel pipes from the 1940s are prone to internal rust accumulation and clogging, necessitating replacement with copper or PEX tubing.
• Metal strips installed at the peak of an asphalt shingle roof expose zinc when hit by rainwater, killing off moss and mold.
• A bleach and water solution sprayed on roof shingles effectively kills moss and mold without damaging underlying roof structures.