Roofing

Flashing exists specifically because shingles alone can’t seal a joint, so its absence isn’t a minor gap; it’s an open door at the roof’s weakest points.

Without one specific, easy-to-overlook component, an otherwise correctly built system stops draining and starts funneling water straight into the wall.

The interweaving with shingles and siding that makes step flashing effective is the same thing that makes repairing it more delicate than other flashing types.

The individual pieces are simple, but getting the overlap, fastening, and integration with counter-flashing all correct at once is where installations commonly go wrong.

The metal itself might have decades left, but the joints and sealant around it are almost always the first thing to actually give out.

Flashing is a distinct component from the shingles or roofing material around it, which is exactly what makes an independent replacement possible.

Roofers reach for different sealants for different jobs on purpose; the five common chemistries genuinely aren’t interchangeable.

A poorly sealed repair is worse than doing nothing, since it can redirect water to a new, hidden entry point that’s harder to trace later.

This is a different problem than rust; here the metal itself is often fine, but the forces holding it in place have gradually given way.

Ordinary rust from age is one explanation, but mismatched metals touching each other is a faster, more preventable cause worth ruling out first.