Fire Door Self-Closers: When a Loft Conversion Actually Needs One

A common belief about loft conversions is that every fire door in the house has to swing itself shut. That is not what Approved Document B says. Chasing a rule that does not exist is how people end up with doors that get wedged open and quietly stop working. Get the closer question right and you spend less while keeping a fire door that actually latches. Get it wrong and you waste money, or fail the loft fire check on a detail you never needed to touch.

What a self-closer actually does

A self-closer, or door closer, is a device that returns a door to the fully closed and latched position every time someone lets go of it. On a fire door that matters because an open fire door does nothing. The protected stair in a loft conversion only holds smoke and flame back if the doors onto it are shut when a fire starts, and people cannot be relied on to close them behind themselves at two in the morning. A closer removes the human from that equation.

The key word is latched, not just closed. A fire door has to be held firmly against its stop by the latch so the intumescent strip can seal the gap when it swells. A closer that brings the leaf to within a centimetre of the frame but cannot push it the last bit against the latch has failed. That gap is exactly where cheap closers let people down.

Closers come in a handful of forms. An overhead hydraulic closer is the familiar box-and-arm unit screwed to the top of the door. Concealed closers hide inside the door edge or the frame. Hold-open retainers keep a door open on purpose and let it close when the alarm sounds. Each has a place, and the wrong one in the wrong place is a common and avoidable mistake.

Does your loft door actually need one?

Approved Document B, Volume 1, which covers fire safety in dwellings, does not require self-closers on fire doors inside a single-family house. Appendix C, paragraph C5, says all fire doorsets should be fitted with a self-closing device, then lists exceptions, and paragraph C5(c) exempts fire doorsets within flats and dwellinghouses. So the stair doors in your own house, the ones a loft conversion pulls into scope, are exempt from the self-closing recommendation. This is guidance for England; Wales, Scotland and Northern Ireland have their own versions that differ in the detail. Approved Document B is reissued by an amendment that takes effect on 2 September 2029, so if your project runs close to that date, confirm the self-closing provisions for dwellinghouses against the version in force. The Approved Document's minimum leaf on a loft escape route is actually E20, an FD20 door, not FD30, though FD30 is widely specified; the choice of leaf is covered on the FD30 fire door page.

The exceptions that do need a closer in a house context are specific. The door between the house and an integral garage must be self-closing and smoke-sealed (Approved Document B, Table C1, item 11a, an FD30S door). Flat entrance doors are expected to self-close. In a house in multiple occupation (an HMO) the expectation depends on the council's licensing standard and the risk: closers are generally expected in higher-risk, bedsit-style HMOs and relaxed for single-household homes and low-risk shared houses. And building control, your insurer, your mortgage lender or a fire engineer can specify a closer on a loft stair door as a condition, at which point it is not optional for you.

C5(c)

The Approved Document B paragraph that exempts fire doors within a dwellinghouse from the self-closing recommendation.

Councils do not all read it the same way, and that is the practical catch. Some building control guidance on loft conversions states plainly that room doors onto the stair do not need to be self-closing, and asks for a closer only on the garage door. Others specify self-closers on habitable-room doors anyway as a local policy. Neither is wrong, because the Approved Document is guidance that your building control body interprets. The money move is to email your building control officer before you buy anything and ask one question: "Do you require self-closers on the loft stair doors, or only on the garage door?" Get the answer in writing. It costs nothing and stops you fitting four closers you did not need, or failing sign-off because you fitted none.

External resource

Approved Document B, Fire safety, Volume 1: Dwellings

The free, official guidance behind the self-closing rules. Appendix C, paragraph C5, covers self-closing devices and the dwellinghouse exemption; paragraph C6 covers hold-open devices; Table C1 covers the garage door.

gov.uk

The types, and why the cheap one fails

Four kinds of device turn up on a domestic fire door. They are not interchangeable, and the gap between the best and the worst is the difference between a door that latches for twenty years and one that gets ripped off in a month.

The overhead hydraulic closer is the box with a jointed arm you see on doors in public buildings. Oil pushed through an adjustable valve controls how fast the door shuts and, on a decent unit, a separate valve controls the final snatch that drives the leaf against the latch. It is cheap and reliable, and it latches. The only real downside is that the arm is visible, which some homeowners dislike on a nice door.

The basic concealed chain-link closer, the Perko R2 and its copies, is the one that causes the trouble. It fits inside the hinge edge of the leaf and the frame, hidden when the door is open, with a spring and a chain doing the work. It is cheap and invisible, which is why fitters reach for it. But the spring action is uncontrolled: it slams or it stalls, and it can fail to overcome the drag of the latch and the intumescent and smoke seals to pull the leaf fully shut. A fire door that rests a few millimetres proud is not a fire door. One installer on a trade forum described a concealed unit that kept snapping and was swapped for an overhead closer, and that uncontrolled action is a common complaint where a concealed closer will not latch.

If you want hidden and reliable, pay for a controlled concealed closer such as a Powermatic. It is a full hydraulic unit inside the door edge, with an adjustable latching action over the last 15 degrees of swing, certified to BS EN 1154 and fire-tested for 30 and 60 minute doors. It latches like an overhead closer and disappears like a cheap concealed one. It also costs more than ten times a basic chain-link closer, which is the trade-off.

The alarm-linked hold-open retainer is a different job. It does not shut the door, it holds it open and lets it close when the alarm goes off, which is covered in its own section below.

Matching the closer to the door: power size

Closers are graded by power size under BS EN 1154, the standard for controlled door-closing devices. The size tells you how much force the closer applies, which has to be enough to overcome the latch and the seals on a given leaf. The size table below is summarised from a fire-door supplier's published explanation of the standard (Safelincs), because the standard text itself is paywalled, but the figures are consistent across the closer makers.

The rule for a fire door is simple: size 3 is the minimum. Sizes 1 and 2 are for ordinary internal doors and are not strong enough to drive a fire door against its seals, so they must never go on one. A standard FD30 flush leaf, 762mm or 838mm wide, normally takes a size 3; check the leaf's stated mass against the 60kg size-3 limit. A wide or heavy leaf, say 926mm or a solid timber door, moves you to size 4. Where the width points to one size and the weight to another, use the larger.

Do not be fooled by the "EN 2-4" printed on the box of a common overhead closer. That is the adjustable range the unit can be set to, not permission to run it at size 2. Set it to 3 or 4 by the door's width and weight. The closer also needs to be CE or UKCA marked and listed on, or compatible with, the door's own fire certification, and it has to be able to close the door from any angle, not just from a few degrees ajar.

Fitting it so it latches

A closer is only as good as its commissioning, and this is the part fitters rush. Get the door right first: the perimeter gap wants to be an even 2mm to 4mm at the head and down both sides, the intumescent and smoke seals fitted and not painted over, and three hinges hung square so the leaf is not binding. A closer cannot rescue a door that is out of square or dragging on a bunched seal. Detail on the seals is on the intumescent strip page, and the door itself is covered on the FD30 fire door page.

Then set the valves in order. Set the main closing speed first, so the door swings shut at a controlled, unhurried pace over most of its travel. Then set the latching speed, the final snatch over the last 10 to 15 degrees that drives the leaf against the latch. A closer slow enough to be quiet across the room will often stall before it latches; one fast enough to latch every time will bang. The balance is in those two valves, and it takes a few goes. Test the door from fully open, and then again with the leaf only 10 degrees ajar, because a closer that latches from wide open can die on the short swing.

Holding a fire door open, legally

People prop fire doors open. It is human, and a wedge under a loft-landing door is the fastest way to kill the fire strategy you paid for. There is a legal way to keep a fire door open, and Approved Document B, paragraph C6, sets it out: a fire door may be held open only by a fusible link that melts in a fire, an automatic release triggered by the fire alarm, or a closer with a built-in delay. A wedge or a tied-back door is neither of those, and is never acceptable.

In a home the practical option is an acoustic hold-open retainer such as a Dorgard, certified to BS EN 1155, the standard for powered hold-open devices. It sits at the base of the door, holds it open, and releases it to close when it hears the alarm sound, typically above about 65 decibels. That ties neatly into the interlinked smoke alarm system a loft conversion already needs, because the alarm network is the trigger. Acoustic units are no good in a genuinely noisy spot; a hard-wired electromagnetic retainer, released by the alarm panel or a power cut, is the alternative and costs more. Either way the door still closes itself in a fire, which is the whole point.

What it costs

Closer prices split cleanly by type, and the spread is enormous. An overhead hydraulic fire-rated closer is the cheap, reliable end. The named branded units run in this range.

The cheapest own-brand overhead closers sit lower, around £20 – £30, and do the job on a garage door. The branded units worth searching are the Dorma TS68, the Rutland TS.5204 and the Briton 1120B. A basic concealed chain-link closer at £30 – £39 looks like a saving until it will not latch and gets replaced. The concealed closer that actually works, a controlled hydraulic unit, is £479 – £520, the price of hidden and reliable at once. An alarm-linked acoustic retainer is £107 – £146. Those concealed, controlled and retainer figures are indicative, single-retailer prices. Screwfix, Toolstation, Safelincs and Ironmongery Direct all stock fire-rated closers.

If you are paying to supply and fit a complete certified fire door with its ironmongery, budget £300 – £600 per door for the leaf, strips, hinges and labour into an existing frame. A closer, where one is actually needed, is an added cost on top of that, not included in it.

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Where you'll need this

Self-closers sit in the fire-safety layer of a loft conversion, specified alongside the doors, the stair and the alarms rather than on their own. Decide early which doors need a closer, based on your building control officer's answer, so nothing is bought twice. The closer goes on at second fix once the door is hung and the seals are in, and gets commissioned then; at sign-off building control checks that any required closer latches the door fully, which is where correct commissioning earns its keep.

The related pages cover the parts a closer depends on: the FD30 fire door it mounts to, the intumescent strip whose drag it has to overcome, and the interlinked smoke alarm system that triggers any hold-open retainer.

Closers turn up wherever a protected route runs through a building, so the detail here applies across loft conversions, flat conversions and any work that creates an HMO, not just a loft.

Common mistakes

The other recurring errors are quieter. People fit closers to every stair door because someone said every fire door needs one, when the Approved Document exempts them and the building control officer never asked for any. An overhead closer gets left at power size 2, where the adjustment dial sat out of the box, too weak to latch a fire door. A door gets wedged open rather than fitted with an alarm-linked retainer. The last one is the easiest to miss: going back after a few weeks to re-set the latching once the seals have bedded in. None of these is expensive to avoid, but each costs a return visit, and the first can cost the sign-off.