Kitchen Hood Damaged, Leaking or Rusted: Repair, Patch or Replace in Singapore

The hood has been in for years and it is starting to show. A seam is weeping brown grease onto the cooking line, a corner has gone rough and rust-coloured, a panel has a dent from a trolley, or the filter rail no longer sits true. Somebody says “just patch it”, somebody else says the whole canopy needs changing, and you have a kitchen to run on Friday night. This post is about how to tell which one you are looking at, and what to ask before you approve either.

We do not publish a price for hood repair or replacement. A hood is built to the size of the cooking line, so a figure given without seeing it would be a guess. What we can give you is the way to read the damage, and the questions that make two quotes comparable.

First, work out what kind of damage it is

“The hood is spoilt” covers very different problems. They sort into four groups, and each group points to a different decision:

• Surface damage. Dents, scratches, dull or stained panels. Ugly, usually harmless to how the hood works.
• Seams and joints that leak. Grease weeping out of a corner, a join or a rivet line, onto the cooking equipment or down the front. This is the one that gets worse quietly, because grease that escapes the hood is grease that is not reaching the filters.
• Corrosion. Rust-coloured staining along joints and edges, flaking, or metal that has gone thin. Check whether it is a stain on sound metal or the metal itself being lost.
• Parts around the hood. Filter rails and brackets that have bent, a grease channel that no longer drains to its collection point, access panels that do not close flat, lighting fittings that have failed.

Stand under the hood with the cooking off and the filters out. Take a photograph of each problem with something in the frame for scale, and one wide shot of the whole canopy. Those photos are the most useful thing you can send anyone who is going to quote.

When patching is the sensible call

A patch makes sense when the damage is local and the metal around it is sound:

• A single seam or corner that has opened up, on a hood that is otherwise tight.
• A dented or bent section that can be replaced as a piece rather than the whole canopy.
• A damaged filter rail, bracket or grease channel that can be cut out and refitted.

On our repair and replacement page we list ducting and hoods among the things we repair: patching, sections, and fabricated replacements where needed. The phrase that matters is “where needed”. A patch is the right answer when it fixes the cause. It is the wrong answer when it covers a symptom, such as sealing the outside of a seam that is leaking because the joint behind it has failed.

When a section or the whole hood should be replaced

Replacement starts to win when repairing would only buy a little time:

• The corrosion is in the metal, not on it. If it is thin, soft or perforated near the joints, patches will keep failing next to the old ones.
• The same seam has been fixed more than once. A second repair of the same place suggests the construction is the problem.
• Grease keeps escaping from several places. A hood that leaks at many joints is no longer capturing and channelling grease the way it was built to.
• The cooking line has changed. If new equipment went under it, a like-for-like repair keeps you with a hood that was already the wrong size. See when a menu change outgrows your kitchen exhaust and our guide to sizing the exhaust hood to the cooking line.
• Cleaning it properly is no longer possible. Riveted joints and hard-to-reach corners that trap grease are a cleaning problem as well as a repair problem.

We fabricate hoods, ductwork, control panels and fans in our own workshop, so a replacement section can be made to fit what is already there rather than waiting on a stock item from someone else. That is a statement about how we work, not a promise about timing: how long a given repair takes depends on the hood and on access to it, and we would rather tell you that after seeing it.

Why the seams matter more than the shine

In our guide to choosing a commercial kitchen exhaust hood we say stainless steel is the standard for good reason: it survives degreasing chemicals and can be cleaned back to bare metal repeatedly. We also say the details that matter over a hood's life are continuous welded seams rather than riveted joints that trap grease, a properly formed grease channel with an accessible collection point, and filters that lift out without tools. Those same details decide how a hood ages. A hood that is damaged at a seam or channel is a hood where the grease path has been changed.

So when you look at damage, look at the grease path before the cosmetics. Where does the grease go after it hits the filters? Does it reach the channel and the collection cup, or is it finding another way out? Our piece on what is behind the baffle filters shows what to look for once the filters are out.

Ask for the repair and the replacement side by side

A fair comparison fits on half a page. Ask for it in writing, by message if that is quicker:

1. What is wrong and how it was confirmed. A photo of the damage and a note on whether the metal itself is affected.
2. What the repair covers and what it leaves alone. If one seam is fixed and the rest are not looked at, you should know.
3. An honest view of how long the repair is likely to hold, in plain words, and what would shorten it.
4. What replacement involves. Which section or whether the full canopy, and what else has to be disturbed: the duct connection, the filters, any pipework that runs along the hood.
5. Downtime for each option. Whether the line can cook tonight, and what happens if it cannot.
6. The cost of each, before the work starts. We quote clearly before doing the work, and so should anyone you are comparing us with.

If the person quoting cannot say why one beats the other, that is worth knowing before you pay for either.

Before anything is cut, check what else is attached to the hood

Hoods are rarely bare metal. Suppression nozzles and their pipework often run along the front, and there may be lighting, sensors or bracketry fixed to the canopy. Before any cutting or welding, tell the contractor what is attached and who services each system, and agree who will disconnect and reconnect them. If your suppression system is serviced by another company, ask for their involvement in writing rather than assuming it will be handled. Hood work that disturbs a suppression line and is never rechecked is the kind of thing that gets found at the worst moment.

Find the cause, not only the damage

Hoods do not leak and corrode for no reason. A hood that is cleaned late, over a heavy-grease cooking line, will have grease sitting against its seams for months. Damp from condensation or washing water that cannot drain can corrode joints faster. A hood that has been dented has often been knocked by a trolley, a ladder or a mop bucket in the same place for years. When you get a quote, ask what caused the damage and whether anything will be done to stop it happening again. A regular hood, duct and fan clean also gives you a fixed night each cycle on which the hood is opened up and looked at, so an early fault is caught before it becomes a leak.

If you are not sure whether the duct above the hood is part of the same problem, our guide on what the kitchen exhaust duct is made of and why it leaks covers the joints higher up, and finding the failing link before anyone replaces a part helps you separate a hood fault from a fan or airflow fault.

Questions to ask before you say yes

1. Is the metal itself damaged, or only stained or scratched?
2. Why did it happen, and what stops it happening again?
3. If we patch, how long should it hold and what would shorten that?
4. If we replace, is it a section or the full hood, and does it match the cooking line as it is now?
5. What is attached to the hood, and who will disconnect and recheck it?
6. Can the kitchen cook tonight, and what are the risks if it does?

We repair and replace exhaust equipment regardless of who originally installed it, on a 24/7 standby line, and for a larger rework the design and build page explains how we handle hood, duct and fan as one job.

Not sure whether to patch or replace? WhatsApp BC Air on 8989 2833 with photos of the damage, where the outlet is and roughly how old the hood is.

Related reading: repair or replace the kitchen exhaust fan · baffle vs mesh hood filters · access panels in a kitchen exhaust duct