The longer answer
Why the corner is the weak spot: "seamless" gutters are seamless along each straight run — but every corner is still a joint. A box miter (pre-formed corner piece) or a hand-cut strip miter joins the two runs, fastened with rivets and sealed with gutter sealant. That sealant lives outdoors through KC's freeze-thaw winters and 100-degree summers, and it eventually dries, cracks, and lets go.
Common miter problems we repair:
- Dried, cracked sealant — the classic slow drip at the corner during rain
- Loose or under-riveted joints — corners that were caulked instead of fastened
- Poorly cut strip miters — gaps too wide for sealant to bridge reliably
- Corners pulling apart — from ice load or fascia movement behind the gutter
The honest repair hierarchy: a sound, tight miter with failed sealant just needs the old sealant stripped and re-sealed. A loose or badly cut corner should be re-riveted or rebuilt — resealing over a moving joint fails within a season or two. If the corner keeps leaking after quality repairs, the underlying issue is usually slope or fascia, not the miter itself.
Corner leaks are a standard part of our gutter repair service across the KC metro — and if you're seeing leaks at multiple corners of an aging system, we'll give you a straight answer on whether repair or replacement is the better spend.
Free in-person walk — usually within 24-72 hours
Written, line-itemed quote. No pressure. Our crew brings 35+ years of combined Kansas City gutter experience.
Book my free quote → Call (816) 469-9563