Why do gutters leak on industrial buildings?
Most leaks come down to water that can’t get away. Industrial roofs collect a lot of rain, and it all has to pass through a few outlets. When one is blocked, water backs up, finds a weak joint or spills over into the building.
The most common causes are:
- Blocked outlets: leaves, silt, moss and bird nests stop water getting into the downpipes.
- Failed joints: gutter sections are bolted together with a seal that breaks down as the building moves.
- Corrosion: steel rusts where wet debris sits against it.
- Damage from foot traffic: people walking in gutters to reach plant or roof lights can open up joints and coatings.
- Old repairs: failed bitumen or mastic patches can trap water and hide corrosion.
Which gutters are most at risk?
Internal gutters are the ones to watch, because they’re inside the line of the wall. A blocked eaves gutter usually overflows outside, where you can see it. A blocked box or valley gutter can overflow into the building, and you may not know until there’s water on your stock, your floor or your electrics.
| Type of gutter | Where it is | What usually goes wrong |
|---|---|---|
| Box gutter | Built into the roof, often behind a parapet | Water sits in it between outlets, so joints and steel fail, and overflow goes inside |
| Valley gutter | Between two roof slopes | Takes water from both slopes, so a blocked outlet can overflow quickly |
| Eaves gutter | Along the outside edge of the roof | Sagging, failed joints and overflow down the wall |
| Concrete gutter | Part of some older building frames | Cracks at the joints between sections |
How do you prevent gutter leaks?
1. Clean them on a schedule
Most commercial buildings need their gutters cleaned about twice a year: at the end of autumn, once the leaves are down, and in spring, to clear whatever built up over winter. Buildings near trees or with bird problems may need more visits.
2. Keep outlets and downpipes clear
An outlet is usually the first place to block, so make sure each one is checked at every clean. Clearing the gutter isn’t enough if the downpipe below it is still blocked.
3. Inspect while you clean
Gutter cleaning is the best time to spot faults, because you can see the gutter’s surface. Ask your contractor to photograph and report any:
- rust, pinholes or lifted coatings
- open or weeping joints
- sagging sections and standing water
- failed earlier repairs
- damage to nearby roof sheets and flashings
4. Deal with birds
Nests and droppings can block gutters and roof drainage. Bath and North East Somerset Council’s guidance makes the same point. If birds are the cause, cleaning alone won’t last, so look at clearing the guano and bird proofing too.
5. Control foot traffic
If people regularly cross the roof to reach plant, agree a safe route that doesn’t involve walking in the gutter.
6. Fix small faults early
A leaking joint is usually much easier to deal with than a corroded run. Our guide to whether commercial gutters can be repaired explains when to choose a patch, a lining or a replacement.
7. Keep a simple record
Note the date of each clean, what was found and what was done. Patterns will show you which gutters need more attention, and you’ll have the records if your insurer or landlord asks for them.
Is it safe to check your own gutters?
Only if you can do it from the ground or from a safe, fixed access point. Don’t send staff onto the roof to take a look.
HSE says all roofs should be treated as fragile until a competent person has confirmed they aren’t, and warns that some roof lights are hard to see in certain light. It also says almost one in five construction deaths involve roof work, and that many of those people were repairing or cleaning roofs, not specialist roofers.
From inside and from the ground, you can safely look for:
- stains on the underside of the roof or around gutter lines
- drips or puddles after heavy rain
- plants growing out of gutters
- water running down an outside wall
- downpipes that stay dry in the rain, or joints that leak
What should you do if a gutter is already leaking?
- Make the area safe: cover or move stock, and keep people clear of wet floors. If water is near electrics, get them checked.
- Note where and when it leaks: take photos, and note whether it happens only in heavy rain. A drip can travel along steelwork, so it may not be directly under the fault.
- Get the gutter cleared: a blocked outlet is often the cause, and you can’t properly inspect a gutter full of debris.
- Then decide on repairs: once it’s clean, it’s easier to see whether you need a joint repair or a full lining.
We clean and repair gutters on factories, warehouses and other large buildings, using gutter vacuums, cherry pickers and mobile platforms. See our gutter cleaning and gutter repairs and lining services.
