Left vs right
End caps are handed. Standing on the ground facing the house, a left end cap closes the left end of the run and a right cap closes the right. They are not interchangeable — the crimp that grips the gutter's front bead is mirrored. Ordering the wrong hand is a classic DIY mistake that ends with a cap that will not seat.
The main types
- Standard left/right — stamped to match the K-style profile. What is on most homes.
- Bay end caps — cut at an angle for bay windows and other runs that terminate at something other than 90 degrees.
- Custom-formed caps — fabricated to match half-round, oversized, or copper profiles where a stamped cap does not exist.
Why end caps leak
The cap itself rarely fails. What fails is the seal behind it. A cap is crimped on and then sealed on the inside face; over ten or fifteen Kansas City summers the sealant goes brittle, shrinks away from the metal, and opens a hairline path. Because the leak is at the very end of the run, it drips in exactly one spot — usually right by a corner of the house where it does the most damage to fascia and siding.
How we repair one
Scraping out old sealant and adding a fresh bead over it does not last. We remove the cap, take the mating surfaces back to clean metal, re-seat it, and seal from the inside so water pressure pushes the seal closed rather than peeling it open. On a seamless run there is no reason to replace the whole section for an end cap — this is a repair, not a replacement.