FD30 Concealed Doors: Fire-Rated Flush to Wall Doors Explained

Concealed doors are designed to disappear: no architrave, no visible hinges, just a slim shadow line where the door meets the wall. But many of the places people want them, such as the hallway of a three-storey house, a flat’s entrance hall or the door through to an integral garage, are exactly the places where building regulations may call for a fire door.

The good news is that you don’t have to choose between the two. Fire-rated concealed door systems exist. The catch is that a fire rating belongs to a tested assembly, not to a door on its own, so you need to know what to look for.

What does FD30 mean?

FD30 is the British way of describing a fire door that has achieved at least 30 minutes of integrity in a fire test to BS 476-22. Integrity means the door stops flames and hot gases getting through. The European equivalent is E30, tested to BS EN 1634-1 and classified to BS EN 13501-2.

You’ll also see FD30S or E30Sa. The “S” or “Sa” means the doorset also restricts the passage of cold smoke, usually with smoke seals.

Approved Document B, the government guidance on fire safety in England, accepts either route for now. Its 2029 amendment, due to take effect on 2 September 2029, moves the fire doorset guidance towards the European classifications.

Where might you need a fire-rated concealed door?

Approved Document B Volume 1 (dwellings) sets out minimum ratings by location. A few examples relevant to homes:

• Protected stairways in houses. In a house with a storey more than 4.5m above ground level, such as many loft conversions, the stair usually needs to be a protected stairway. Doors onto it should be at least E20 (FD20).
• Between a house and an integral garage. At least E30Sa (FD30S), and the door should be self-closing.
• Flats. Doors onto a protected entrance hall or landing within a flat should be at least E20 (FD20). Flat entrance doors onto common areas need higher performance and a self-closing device.

FD30 doors exceed a 20-minute requirement, which is one reason they’re so widely used in homes. Your building control body or approved inspector confirms what your project needs, so check with them early, ideally before the walls are built.

Why a concealed door is harder to fire rate

A standard fire door is hung in a timber frame with butt hinges and covered by architraves. A concealed door changes almost every part of that:

• The frame. Concealed frames are usually aluminium profiles plastered into the wall, with no architrave to cover the joint.
• The hinges. Concealed hinges sit in deep recesses in the door edge and frame, removing material where fire attacks first. Approved Document B says the essential parts of fire door hinges should have a melting point of at least 800°C, unless they’ve been shown to be satisfactory as part of a tested fire doorset.
• The latch. Many concealed doors use magnetic latches rather than a conventional latch.
• Both faces. Fire doors must be tested from each side separately, which matters for concealed doors that can be hung to push or pull.

Approved Document B also says test evidence must apply to the complete installed assembly, and that small differences in detail can significantly affect the rating. So you can’t take a fire-rated door leaf and hang it in any flush frame with any hinges and call it FD30. The combination has to be tested or assessed together.

What a tested FD30 concealed system looks like

A good example is the Rocket Door Frames Ultra Flush system, which we supply as the Invisible Frameless Hidden Concealed FD30 Fire Door. Rocket says its ultra flush concealed door system was independently tested at Warringtonfire, a UKAS-accredited laboratory, and achieved a full FD30 rating.

According to the product information, the set includes:

• An aluminium frame that can be installed four ways (left or right, push or pull) and is designed to grip the plaster for an architrave-free finish
• A pre-routed 44mm solid flush primed door
• Three-way adjustable concealed hinges, hinge cover plates and a strike plate
• A magnetic latch, with handle, bathroom thumbturn or key cylinder options
• Bumper seals and the intumescent kits

It can be used with metal or timber stud walls or masonry, with a minimum stud of 63mm. Handles aren’t included, so you choose your own.

When you compare systems, look for the same things: a named, accredited test lab, a clear statement of what was tested, and a kit that includes the fire-critical parts rather than leaving you to source them.

The wall matters too

A fire door is only as good as the wall it sits in. Where Approved Document B calls for a protected stairway, it describes the enclosure as fire-resisting construction (minimum REI 30) as well as the doors. Make sure the stud, boarding and plaster around your concealed frame are built to suit, following both the frame manufacturer’s instructions and your building control requirements. Our guide to concealed door frame details explains how these frames sit within the wall build-up.

Hardware, closers and finishing

Handles and latches

Stick to the latch options supplied or approved for the system. If you’re adding handles, check they’re suitable for fire doors and won’t require changes to the door that the test evidence doesn’t cover.

Self-closers

Approved Document B says fire doorsets within houses and flats don’t need self-closing devices, but some locations do, including the door between a house and an integral garage. If yours needs one, read our guide to concealed door closers and only fit a closer that the door’s evidence allows.

Painting

Concealed doors are almost always painted to match the wall. Paint the door faces as directed by the manufacturer. Fire safety guidance generally says to keep paint off smoke seals, hinges and other moving parts, and to follow the manufacturer’s instructions on intumescent strips.

What to check before you buy

1. The rating you need. E20, E30 or E30Sa? Confirm with building control.
2. The test evidence. Who tested it, to which standard, and does it cover your door size, opening direction and hardware?
3. Your wall build. Stud size, boarding and plaster thickness must suit the frame.
4. Sizes and lead times. Fire-rated concealed doors come in set sizes. Measure carefully using our guide on how to measure for a concealed door.
5. Installation. Fire doors only perform if they’re fitted correctly. Use an experienced installer and follow the manufacturer’s instructions exactly.

If a concealed swing door won’t work in your layout, a fire-rated pocket door may. See FD30 pocket doors explained and our FD30 pocket door kits.

Looking after an FD30 concealed door

Once it’s fitted, don’t trim the door, add extra hardware or remove seals without checking with the manufacturer, as any of these can affect the rating. Check now and then that it closes fully and the seals are intact. In England, the Fire Safety (England) Regulations 2022 require responsible persons in multi-occupied residential buildings over 11 metres to check communal fire doors at least every three months and to make best endeavours to check flat entrance doors at least every 12 months.

Frequently asked questions

Can a concealed door be a fire door?

Yes. Several manufacturers offer concealed, flush to wall systems that have been fire tested as complete assemblies. The door, frame, hinges, latch and seals must all be part of the tested system.

Can I put an FD30 door into a standard concealed frame?

Not if you need a fire rating. Approved Document B expects the test evidence to cover the complete installed assembly, so the frame and hardware must be part of what was tested or assessed.

Do FD30 concealed doors need a self-closer?

Not always. Fire doors within houses and flats don’t need self-closing devices under Approved Document B, but some locations do, such as the door to an integral garage. Check with building control.

Is an FD30 concealed door the same as FD30S?

No. The “S” means the door also restricts cold smoke, usually with smoke seals. If your location calls for FD30S (E30Sa), check the system’s evidence covers smoke control.

Can I paint an FD30 concealed door?

Yes, the faces can usually be painted to match the wall. Follow the manufacturer’s instructions and keep paint off seals, hinges and other moving parts.

Find a fire-rated concealed door for your project

If you need a hidden door that meets fire safety requirements, explore our concealed and flush to wall doors and fire doors, or contact us with your sizes and we’ll help you find a tested option.