Commercial gutter repair covers the diagnosis and fix of leaks, sagging, clogs, and lining failures on the larger box, K-style, and built-in gutter systems that drain commercial and industrial roofs. Most single-point repairs run $100 to $450 in 2026, while relining a failed built-in gutter is priced per linear foot. The right call depends on the system type, the failure mode, and whether the owner or a tenant holds the maintenance obligation under the lease. This guide breaks down each of those, with 2026 cost ranges no thin contractor page gives you.
How commercial gutter repair differs from residential
Commercial gutter repair differs because the systems are bigger, often built into the roof structure, and tied to flat or low-slope drainage rather than a simple pitched-roof eave. Commercial buildings commonly run 6-inch and 7-inch K-style, heavy-gauge steel box gutters, or internal built-in gutters set behind a parapet wall. Houses typically use 5-inch aluminum on an open eave.
That size difference matters for repair. A commercial roof sheds far more water per storm, so an undersized or partly blocked gutter overflows fast and drives water behind the fascia, into the wall cavity, or onto a flat membrane where it ponds. Steel and copper are common commercial metals, and both need soldering or welding for a lasting seam fix, not just a bead of sealant.
Access and safety add cost too. Repairs on a two or three story building require lifts or tie-off rather than a ladder, which is part of why commercial labor runs higher per hour. For the drainage side of a low-slope roof, see how a commercial flat roof repair ties into the gutter and scupper system.
Common commercial gutter problems and how each is repaired
Most commercial gutter failures fall into seven repeatable categories, and each has a standard repair method and price band. Leaking seams and sagging runs are the two most common service calls, followed by clogs and rust perforation on older steel. The table below maps the problem to the fix and the 2026 commercial cost range.
| Problem | Standard repair method | 2026 commercial cost range |
|---|---|---|
| Leaking seams or joints | Reseal with commercial-grade polyurethane, re-solder steel or copper joints | $100 to $300 per repair |
| Sagging or pulled-away section | Refasten with hidden hangers, reset the slope | $75 to $300 per section |
| Clogged gutter or downspout | Clear debris, hydro-flush, snake the downspout | $150 to $400 per service |
| Holes or rust perforation (steel) | Metal patch plus sealant, or spot weld | $150 to $400 per patch |
| Failed box or built-in gutter lining | Reline with EPDM membrane or liquid coating | $10 to $40 per linear foot |
| Detached or undersized downspout | Reattach, or upsize to 3×4 or 4×5 outlet | $50 to $250 per downspout |
| Damaged end cap or miter | Replace cap, reseal the miter corner | $75 to $200 per fitting |
The failure modes overlap with a house, but the fix rarely does. A residential leak gets a sealant bead; a commercial steel box gutter usually needs the joint cleaned and re-soldered, or the whole trough relined. For the lighter version of these fixes, our guide to standard gutter repair services covers the residential side.
How much does commercial gutter repair cost in 2026
Commercial gutter repair costs $100 to $450 for a typical single-point fix in 2026, with labor at roughly $50 to $150 per hour depending on building height and access. Leaks average $100 to $300, sagging and realignment $75 to $300, and a clogged system $150 to $400, per contractor pricing data compiled across the U.S.
Relining or replacing runs on a per-linear-foot basis. A full commercial gutter replacement in 6-inch or 7-inch steel box profile commonly lands at $25 to $35 per linear foot installed, while 6-inch aluminum commercial K-style runs closer to $8 to $20 per linear foot. Custom fabricated built-in gutters and copper cost more and are quoted per job.
Height, metal type, and the length of the run drive the number more than anything else. A 200 foot steel box gutter on a warehouse is a different job from a 40 foot aluminum run on a strip retail unit, even when the failure looks the same.
Can commercial box and built-in gutters be repaired
Yes, commercial box and built-in gutters can usually be repaired rather than torn out, and relining is the standard method. A built-in gutter is a trough framed into the roof structure behind a parapet or at the eave, so replacing it means opening the roof. Relining avoids that by installing a new waterproof surface inside the existing trough.
The two common relining systems are a fully adhered EPDM or TPO membrane, and a liquid-applied coating such as a reinforced polyurethane or silicone. Both bridge old soldered seams and rust pits that no longer hold a bead of sealant. A membrane reline typically lasts longer; a liquid coating is faster on a complex shape with many corners.
Older soldered steel and copper box gutters can also be spot-repaired by cleaning the joint and re-soldering, which holds well when the surrounding metal is still sound. Once perforation spreads across the trough floor, relining is the more durable answer. Our full breakdown of box gutter systems covers how these troughs fail and drain.
Repair or replace: the commercial threshold
Repair a commercial gutter when the damage is localized and the metal is otherwise sound; replace when failure is spread across most of the run or the profile is undersized for the roof. A good working rule is the one-third test: if more than about a third of a run is leaking, rusted, or pulling away, spot repairs cost more over two or three years than a single replacement.
Undersizing is the other trigger. If a gutter overflows in normal rain even when clean, the trough or downspouts are too small for the roof area, and repairing seams will not fix a capacity problem. In that case the correct move is to upsize the profile or add downspouts, which counts as replacement, not repair.
Slope faults sit in between. A gutter that ponds because it was hung flat can often be re-hung to the correct gutter slope without new metal, which is a repair. If the fascia or structure behind it has rotted, the fix expands into carpentry.
The commercial gutter repair process, step by step
A professional commercial gutter repair follows a set sequence so the fix addresses the cause, not just the symptom. Skipping the water test is the most common way a “repaired” gutter leaks again in the next storm.
- Inspect and water-test. Run water through the system to locate every leak point, overflow, and low spot, and check the fascia and roof edge for existing damage.
- Identify the system and failure mode. Confirm whether it is K-style, box, or built-in, and whether the issue is a seam, slope, clog, or capacity problem.
- Scope and quote. Price the specific repair against replacement for that run, and document the recommendation.
- Clean and prep. Remove debris, dry the trough, and grind or clean any seam or rust area to be sealed, soldered, or relined.
- Execute the repair. Reseal, re-solder, refasten, or reline as the failure mode requires, using commercial-grade materials.
- Verify slope and flow. Water-test again to confirm the trough drains fully to the downspouts with no ponding.
- Document for the owner or insurer. Photograph before and after and note the work for the maintenance record or any claim.
Who pays for commercial gutter repair, owner or tenant
Who pays for commercial gutter repair depends on the lease structure, and it often falls on the tenant in a triple net (NNN) arrangement and on the owner in a gross lease. Gutters are part of the building envelope and roof drainage, so the obligation usually tracks whoever the lease assigns roof and exterior maintenance to.
In many single-tenant NNN leases, the tenant carries roof and gutter upkeep, though structural roof replacement may stay with the owner depending on how the lease is written. In multi-tenant buildings, exterior and common-area maintenance is frequently the landlord’s responsibility and recovered through common area charges. These allocations vary by lease and jurisdiction, so the written terms control.
Insurance can apply when the damage comes from a covered event such as a storm rather than wear or deferred maintenance. Sudden hail or wind damage to gutters may be claimable, while gradual rust and clog-driven overflow generally is not. Read the specific policy and lease before assuming coverage.
How to hire a commercial gutter repair contractor
Hire a commercial gutter contractor who works on your system type and metal, carries commercial liability and workers’ compensation coverage, and puts the repair-versus-replace recommendation in writing. Many residential gutter installers do not fabricate or solder heavy steel box gutters, so match the crew to the job.
- Verify commercial experience with box, built-in, or heavy-gauge steel systems, not just residential aluminum.
- Confirm insurance, including general liability and workers’ compensation, given the fall exposure on commercial roofs.
- Get an itemized quote that separates cleaning, repair, and any recommended replacement with per-linear-foot pricing.
- Ask for a water test after the work and before-and-after documentation for your maintenance file.
- Check the warranty on both labor and any membrane or coating used for a reline.
For the wider context of who does exterior and drainage work on commercial buildings, start with the roof systems and drainage basics in our learn hub.
Frequently asked questions
How much does commercial gutter repair cost?
A typical single-point commercial gutter repair costs $100 to $450 in 2026, with labor around $50 to $150 per hour. Leak repairs average $100 to $300, sagging or realignment $75 to $300, and clearing a clogged system $150 to $400. Relining a failed box or built-in gutter is priced per linear foot, commonly $10 to $40. Building height, metal type, and run length move the final number most.
What is the difference between commercial and residential gutters?
Commercial gutters are larger and often structural. Buildings commonly use 6-inch or 7-inch K-style, heavy-gauge steel box gutters, or built-in troughs behind a parapet, while houses use 5-inch aluminum on an open eave. Commercial systems handle far more water, use steel and copper that need soldering, and require lifts or fall protection to service, all of which raise repair cost per foot.
Can a commercial box gutter be repaired instead of replaced?
In most cases, yes. A commercial box or built-in gutter can be relined with an EPDM or TPO membrane, or with a liquid-applied coating, which restores a watertight surface without opening the roof structure. Sound soldered seams can also be spot-repaired. Full replacement becomes the better value once rust or leaks cover more than about a third of the run.
How often should commercial gutters be inspected?
Inspect commercial gutters at least twice a year, in spring and fall, plus after any major storm. Buildings near trees or with large flat-roof drainage areas may need quarterly cleaning to prevent clog-driven overflow. Regular inspection catches small seam leaks and slope faults before water reaches the fascia, wall cavity, or roof membrane, where repairs cost far more.
Who is responsible for gutter repair in a commercial lease?
It depends on the lease. In a triple net (NNN) lease, the tenant often carries roof and gutter maintenance, while in a gross lease the owner usually does. Multi-tenant buildings commonly assign exterior and common-area upkeep to the landlord, recovered through common area charges. Because these terms vary by lease and jurisdiction, the written agreement controls who pays.
What size gutters do commercial buildings use?
Commercial buildings typically use 6-inch or 7-inch K-style gutters, steel box gutters, or custom built-in troughs, versus the 5-inch residential standard. The larger profile and bigger 3×4 or 4×5 downspouts handle the higher water volume shed by large or flat roofs. Undersized gutters that overflow in normal rain usually need upsizing rather than seam repair.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.