Fire doors are one of the most important, and most misunderstood, parts of a building’s fire safety setup. They’re designed to hold back smoke, heat, and flames for a set period of time, giving people a window to get out safely. That protection depends entirely on the door staying intact, which is why so many landlords, tenants, and tradespeople end up asking the same two questions: can you drill into one, and can you paint it.
I get asked this a lot on jobs. Most recently, I was called out to a rental property to repaint a fire door that had already been painted once before, which is exactly the kind of situation where the rules matter more than people expect. Here’s what I’ve learned, backed up by the guidance from fire safety specialists Ecosafe.
Can You Drill Into a Fire Rated Door?
Yes, but only within limits, and only in certain places. Fire doors are engineered as a complete system, so every hole you add is a potential weak point in that system.
How many holes can you drill in a fire door?
There’s no single number that applies to every door. It depends on the door’s thickness, which in turn determines how long it can hold back fire. A thin FD30 door has less material to work with than a thicker FD90 or FD120 door, so the number and placement of holes it can safely take will differ.
What size hole can you drill in a fire door?
As a general rule, hole diameter shouldn’t exceed one inch (25mm), with cylinder holes for locks being the main exception to that limit. Anything larger starts to compromise the door’s core and its ability to hold its fire rating.
What happens if you drill too many holes, or holes that are too big?
You risk breaking the door’s fire rating altogether. A door that’s been over-drilled may no longer perform to its FD30, FD60, FD90, or FD120 rating, even if it looks fine from the outside. This is exactly the kind of damage that gets picked up in a fire risk assessment, and it’s the landlord or responsible person who’s on the hook for it, not just the door.
If a door’s been compromised beyond repair, replacing it with a veneered fire door blank cut to size is usually more cost-effective than a full pre-hung replacement door.
What should you do before drilling into a fire door?
Speak to the door’s manufacturer or a qualified fire door maintenance firm first. They can tell you whether the door you’re working on can take another hole at all, and if so, where and how big. It’s a five-minute phone call that can save you from having to replace an entire fire doorset.
Can You Paint a Fire Door?
Yes, fire doors can generally be painted, but there are a few rules worth knowing before you pick up a brush.
Do you need special paint for a fire door?
Use a fire-rated paint. It’s formulated to be non-flammable and won’t interfere with the door’s performance the way an ordinary household paint might. Keep the coats thin, and avoid building up multiple layers over time, since a thick paint build-up can affect how the door seals and closes.
If you’re weighing up fire-retardant coatings more generally, I’ve covered how they work on timber structures in my guide to fire protection and finishing for outdoor workshops.
Can you paint over an already painted fire door?
Yes, this is the situation I ran into on the rental job I mentioned earlier. The same rules apply as painting a bare door: use a fire-rated product, keep it thin, and don’t paint over the parts listed below.
What parts of a fire door should you never paint?
Hinges, handles, and the fire seals running around the door’s edge should stay paint-free. These components need to move and function exactly as designed, and paint can gum up hinges or interfere with how the intumescent seals expand in a fire.
Can you use glow-in-the-dark paint on a fire door?
In some cases, yes. Glow-in-the-dark or photoluminescent paint can be used on fire doors, and it has a genuine safety benefit: it makes the door easier to spot in low light or smoke-filled conditions during an emergency.
Understanding Fire Door Ratings (FD30, FD60, FD90, FD120)
Fire doors are categorised by an FD rating, which tells you the minimum number of minutes the door can hold back fire and heat. The rating you need for a given door is typically decided by whoever’s responsible for the premises.
- FD30 – 30 minutes minimum fire resistance. The most common rating for residential settings.
- FD60 – 60 minutes minimum fire resistance. Typical in commercial and industrial buildings, or areas with a higher fire risk.
- FD90 – 90 minutes minimum fire resistance. Used where extended protection is needed.
- FD120 – 120 minutes minimum fire resistance.
These figures are minimums, not guarantees on their own. A row of FD30 doors placed along an escape route works through compartmentalisation, where each door adds its own delay, and those delays stack up to buy real time overall. That effect only holds if the doors haven’t been compromised by over-drilling, thick paint, or damaged seals.
The Regulations Behind Fire Doors
A few key pieces of legislation and guidance sit behind all of this:
- BS 8214:2016 and BS 9999:2017 – British Standards covering the specification, installation, and maintenance of fire doors, and fire safety in building design and management more broadly.
- Building Regulations 2010, Part 8 – Sets out fire safety requirements for buildings, expanded on by Approved Document B (Volume 1 for dwellings, Volume 2 for non-dwellings), with Appendix C dealing specifically with fire doorsets.
- Regulatory Reform (Fire Safety) Order 2005 – Requires whoever is responsible for a work premises or rented property to carry out a proper fire risk assessment, and to put suitable measures in place based on it. You can read the full text of the order on legislation.gov.uk.
Final Thoughts
Fire doors give a false sense of simplicity: they look like an ordinary door, but they’re a tested, rated system. Drilling and painting are both fine within limits, and both are very easy to get wrong in ways that aren’t obvious until the door’s actually tested by a fire. If you’re not certain a hole or a paint job falls within the rules for your specific door, it’s worth a quick call to the manufacturer or a qualified fire door maintenance firm like Ecosafe before you start.
