Why this matters before you do anything else

Canopy and retractable are the two gear systems used on UK up-and-over doors, and they are not interchangeable. A canopy-gear door has its springs and pivot mechanism mounted across the top of the fixing frame, so the whole door tilts out and up as one panel, leaving roughly a third of the door hanging outside the garage line when open. A retractable-gear door has springs and tracks running back along both sides, so the door retracts fully inside the garage when open, with almost no forward swing.

Ordering a spring, cable or roller for the wrong gear type will not fit. Quoting to automate a canopy door as if it were retractable will produce a door that fights the operator. Getting this identification right first is the gate that every other up-and-over repair or automation decision sits behind.

The decision tree: look at your own door

1. Open the door fully and stand to the side. Does the top of the door swing out past the face of the garage before it lifts clear, so a third or so of the panel sits outside the brickwork line when open? If yes, this points to canopy gear. If the door tucks almost entirely inside the garage with barely any forward swing, this points to retractable gear.
2. Look at where the springs are. Canopy gear has one or two springs mounted horizontally across the head of the fixing frame, above the door, usually behind a plastic or metal cover. Retractable gear has a spring running along each side track, roughly at door height, usually visible as a coiled unit partway along each horizontal track arm.
3. Measure the width of the opening. Canopy gear is only fitted up to approximately 2438mm (8ft) wide. If your structural opening is wider than that, or the door is a double, it is retractable gear by necessity — canopy gear cannot span it.
4. Check whether it is a double door. Retractable gear is the standard fitting for all double up-and-over doors in the UK. If you have a double door, treat it as retractable unless you have visually confirmed otherwise using steps 1–2.
5. Look for side-mounted tension adjusters. Retractable gear has a visible adjustment mechanism — usually a series of holes or a ratchet — on each side track, used to set spring tension to match the door's weight. Canopy gear has no equivalent side adjuster; its tension is set at the head.

Canopy gear: characteristics and limitations

Canopy gear is the simpler, cheaper mechanism and is common on older and lighter single doors. Springs and the pivot mechanism sit entirely at the head of the frame, which keeps the side tracks minimal — often just a short guide rail rather than a full length track. Because the door swings outward before lifting, canopy gear is a poor candidate for automation: the outward arc makes it harder to fit a reliable operator arm, and the mechanism's design ceiling around 2438mm width rules it out for most double doors and many wider single openings. Where automation is wanted on a canopy-gear door, some installers will recommend converting to retractable gear first rather than fighting the geometry.

Retractable gear: characteristics and why it automates better

Retractable gear uses full-length side tracks with a spring and cable arrangement on each side, individually tensioned to the weight of the door. Because the door retracts almost entirely inside the garage with minimal forward swing, the motion is far more predictable for an operator arm to follow, which is why retractable gear is the easiest and safest up-and-over mechanism to automate. It is also the only option once a door exceeds the canopy width ceiling, and it is the standard fitting on every double up-and-over door sold in the UK.

Still not sure? What to do next

If you have been through the checks above and are still unsure, take photos of the springs and the fully-open door from the side and send them to a UK garage door engineer rather than ordering parts speculatively — the wrong spring or roller for the gear type will not fit and most suppliers will not accept it back once installed. Never attempt to inspect or adjust the springs yourself while the door is under tension.

Two different sizing systems: thrust vs torque

UK garage door operators are sized in two different ways depending on the door mechanism, and mixing them up is a common source of confusion when comparing products.

• Arm operators (used on up-and-over and sectional doors) are typically rated in newtons (N) of linear thrust force — the push/pull force the arm can exert to move the door through its arc or vertical travel.
• Tubular motors (used inside the roller barrel of roller shutter and roller garage doors) are rated in newton-metres (Nm) of rotational torque — the twisting force available to wind the curtain onto the barrel.

Both figures describe the same underlying idea — how much force the motor can deliver — but they are not directly comparable numbers, so always check which rating a given product quotes before comparing two operators.

Sizing a tubular motor for a roller door

A tubular motor's Nm rating needs to comfortably exceed the torque required to lift the curtain, including a safety margin for friction, temperature and age-related stiffening of the mechanism. The main factors that drive the required torque are:

• Curtain weight — heavier slat gauges (see 55mm vs 77mm slat guidance) and insulated aluminium curtains need more torque than lightweight steel.
• Barrel diameter — a larger barrel gives more mechanical leverage, so needs less torque for the same curtain weight than a smaller barrel would.
• Door height — taller doors mean more curtain wound onto the barrel and a longer lever arm effect as it winds, increasing peak torque demand.

An underpowered tubular motor typically shows itself as slow operation, motor humming without full movement, or repeated thermal cut-out trips on hot days or after prolonged use — the motor's internal thermal protection is doing its job by shutting down before it burns out, but it means the unit is undersized for the door.

Sizing an arm operator for up-and-over and sectional doors

Arm operators for up-and-over and sectional doors are matched primarily to door weight and, for up-and-over doors, gear type. A retractable-gear up-and-over door automates predictably because the arm follows a near-straight vertical path; canopy gear's outward swing is harder for a standard arm operator to follow reliably, which is why canopy doors are considered poor automation candidates (see the canopy vs retractable guide). Sectional doors, which travel on a fixed vertical-then-horizontal track, are generally the most predictable to automate and size correctly because the door's path never varies.

An installer will typically ask for the door's weight, dimensions and gear type before quoting an operator, because these determine both the force rating needed and whether the existing spring balance is doing enough of the lifting work — a well-balanced door needs the operator to do far less work than an unbalanced one.

Why oversizing is not automatically safer

It might seem safer to fit an operator with more force than the door strictly needs, but UK operators must comply with BS EN 12453, which sets force limits on power-operated doors specifically to prevent injury if the door contacts an obstruction — a person, a pet, a parked bicycle — during travel. An operator that is significantly oversized for the door can exceed safe contact-force limits before its safety systems react, so sizing is about matching the operator correctly to the door, not simply picking the most powerful unit available. This is one reason self-installing an operator without checking its rating against the door is not straightforward, and why professional installation includes setting the correct force and limit parameters.

What to tell an installer or supplier

When getting a quote or buying an operator, have the following ready: door type (up-and-over, sectional, or roller), gear type if up-and-over (canopy or retractable), approximate door weight or dimensions, and whether the door is currently manual or already has a worn-out operator being replaced. This lets a supplier match the Nm or N rating correctly the first time, rather than guessing and risking an undersized unit that trips out or an oversized one that needs its force limits carefully set.

What the numbers actually describe

The 55mm and 77mm figures refer to the height of each individual slat that makes up the roller curtain — the horizontal aluminium or steel strip that repeats up the door and winds onto the barrel. A taller slat profile is inherently stiffer for the same material gauge, which is why the larger 77mm profile is marketed as the stronger, more premium option, typically used on taller doors, wider doors, or where the buyer specifically wants extra rigidity and thermal performance.

Strength and rigidity

A taller slat resists bowing and flex better across a wide opening, which matters most on double garage doors or unusually tall single openings where the curtain has more unsupported width or height to hold rigid against wind loading. On a standard single garage opening, both profiles are generally more than adequate; the difference becomes more noticeable as door width increases.

Insulation and thermal performance

Insulated roller curtains — where the slat is a twin-wall or foam-filled aluminium extrusion rather than solid steel — perform better in the 77mm profile simply because there is more depth in the slat to hold insulating foam. Where thermal performance matters (see the insulation and U-values guide for a fuller treatment), the deeper profile gives the manufacturer more room to build in insulation without compromising strength.

Weight and the knock-on effect on the operator

A 77mm curtain is heavier than an equivalent 55mm curtain of the same width and height, both because there is more material per slat and because insulated 77mm options add foam fill weight. This matters directly for automation: a heavier curtain needs a higher-torque tubular motor to wind it reliably (see the operator motor sizing guide), so specifying 77mm slats on a door that will be electric is not a decision to make in isolation from the motor spec.

Which one for which situation

The general position: permitted development

Under the Town and Country Planning (General Permitted Development) Order, most alterations to an existing house — including replacing a garage door with a similar or different style, colour or material — fall within permitted development rights and do not need a planning application. This covers the vast majority of straightforward like-for-like or upgrade replacements on standard houses.

Conservation areas

Inside a conservation area, permitted development rights are more restricted, and some local planning authorities specifically control alterations that affect the external appearance of a property, including garage doors, particularly where the garage faces a road or is otherwise visible from a public place. The rules vary by council, so checking with the local planning authority before ordering a door is the safe approach if the property sits within a designated conservation area.

Article 4 directions

An Article 4 direction is a specific local order that removes some or all permitted development rights for a defined area, sometimes covering an entire estate or street rather than a formally designated conservation area. Where an Article 4 direction applies, changes that would normally be permitted development — including garage door replacement — may require a full planning application. Article 4 directions are checked via the local council's planning portal or by contacting the planning department directly, as they are not always obvious from the street.

Listed buildings

Any change to a listed building, including its garage if the garage is part of the listing or within its curtilage, generally requires listed building consent regardless of permitted development rights, which apply separately and do not override listed building controls. This applies even to minor changes and even where the garage door itself is not of particular historic interest — consent is about protecting the building's character as a whole.

Flats and maisonettes

Permitted development rights generally apply only to houses, not to flats or maisonettes, so a garage door replacement on a flat or maisonette in the UK typically needs planning permission regardless of the area's designation. This is one of the most commonly missed rules, because owners assume the same permitted development position as a standard house applies — it does not.

What to actually do before ordering a door

If the property is a standard house outside a conservation area, without an Article 4 direction and not listed, a straightforward garage door replacement is very likely permitted development and no application is needed. In every other case — conservation area, Article 4, listed building, or flat/maisonette — check with the local planning authority's planning department before ordering, since getting this wrong can mean removing and replacing a door that has already been fitted.

The key distinction: product certification, not installer accreditation

PAS 24, TS 007, LPS 1175 and Secured by Design all certify that a specific door product, tested in a specific configuration, meets a defined resistance-to-attack standard. None of them are qualifications an installer personally holds or joins — an installer either supplies and fits certified products or they do not. Be cautious of any installer implying they are themselves "PAS 24 accredited" or "Secured by Design" as a business, since these are product marks, not installer memberships.

PAS 24

PAS 24 is a British security standard covering doors and windows in domestic and light commercial buildings, testing resistance to physical attack using methods a typical opportunist burglar might use, such as levering. A garage door or its access door certified to PAS 24 has been tested against defined attack scenarios and passed to the standard's criteria.

TS 007

TS 007 is a standard specifically focused on door hardware — cylinders, locks and related components — commonly seen on door and window furniture rather than the door leaf itself, often marked with a star rating. On a garage door with a pedestrian access door, TS 007-rated hardware indicates the lock cylinder itself has been tested against snapping and similar attacks.

LPS 1175

LPS 1175 is a certification scheme with graded security ratings, testing resistance to forced entry using a range of tools and timed attack methods, with higher grades indicating resistance to more determined and better-equipped attempts. It is used across a wide range of security products, including some higher-specification garage doors and shutters, and the grade achieved tells you the level of attack the product was tested to withstand, not a pass/fail on a single scenario.

Secured by Design

Secured by Design is a police-backed initiative that recognises products — including some garage doors — meeting relevant security standards such as PAS 24. It is awarded to manufacturers' products, and cannot be joined or held by an installer as a business; an installer can only state that they supply and fit Secured by Design-recognised products, never that they themselves are Secured by Design accredited.

What to actually ask an installer

Rather than asking whether an installer "is" accredited to any of these standards, ask which specific door products they supply carry PAS 24, TS 007 or LPS 1175 certification, and ask to see the manufacturer's certification for the exact model being quoted. A reputable installer will be able to point to product-level documentation; a vague answer about the company itself being "certified" is worth double-checking.

What a U-value actually measures

A U-value measures how much heat passes through a material per square metre for each degree of temperature difference between inside and outside, expressed in W/m²K — the lower the number, the better the insulation. It is a standard measure used across UK building products, so it lets you compare a garage door's thermal performance directly against other building elements like walls and windows, though a garage door's overall performance also depends heavily on the seals around its edges, not U-value alone.

How panel construction affects U-value

An uninsulated single-skin steel garage door panel is essentially a single sheet of profiled steel with no thermal barrier, which is why single-skin doors have relatively poor U-values. An insulated panel sandwiches a layer of rigid foam — commonly polyurethane — between two skins of steel or aluminium, and the thickness and quality of that foam core is what drives the improvement in U-value. Thicker foam cores and continuous foam-to-skin bonding (rather than an air gap) generally perform better than thinner or less well-bonded constructions.

Typical U-value ranges by construction

These are typical ranges seen in UK-market insulated door products rather than a single fixed figure — the exact value depends on the specific panel thickness and foam density of the model bought, and a manufacturer's own published U-value for the exact product should be used for anything requiring a precise figure, such as a Building Regulations submission.

When insulation genuinely matters

• Attached, heated garages where warm air can escape through the door into an unheated space, or where the garage itself is heated.
• Garages used as a workspace, gym or hobby room, where comfort at a stable temperature matters day to day.
• Integral garages under living space, where poor door insulation can contribute to a cold floor above and increased heat loss from the house overall.

When it is not worth paying extra for

For a detached, unheated garage used purely for storage, vehicle parking or occasional DIY, the heating-cost payback from an insulated door alone is far less compelling, because there is no heated space to lose warmth from in the first place. In that scenario the case for insulation shifts to secondary benefits — reduced condensation, marginally quieter operation, slightly better durability — rather than a heating bill saving, and the extra cost may be better spent elsewhere unless those secondary benefits matter to you.

Structural opening vs drive-through width

The structural opening is the full width and height of the brickwork or masonry gap before any frame is fitted — this is the number a builder or architect would use. The drive-through width (sometimes called the clear opening) is the usable width once the door's fixing frame is installed inside that structural opening, which is always somewhat narrower because the frame itself takes up space on both sides. Confusing these two is the most common mistake reported when ordering garage doors, because the drive-through figure — the one that actually matters for whether a car fits through — is smaller than the structural opening by the width of the frame on each side.

The reference opening used across this site's pricing, 2290mm × 2250mm, is a structural opening figure for a standard UK single garage.

Step-by-step: what to measure

1. Structural width — measure the full width of the brickwork opening at three heights (top, middle, bottom), and use the smallest figure, since openings are rarely perfectly square in older garages.
2. Structural height — measure from the floor to the underside of the lintel at both the left and right sides, again using the smaller figure if they differ.
3. Headroom — measure from the underside of the lintel up to the ceiling or first obstruction (roof timbers, a beam, pipework). This space is needed for the door's tracks and, for retractable or canopy up-and-over gear, the spring mechanism at the head of the frame.
4. Side room — measure the depth of clear wall available on each side of the opening, needed for the vertical tracks on a sectional door or the side gear on a retractable up-and-over door.
5. Floor level and slope — check whether the garage floor slopes toward the opening (common for drainage) as this can affect the door's fit and seal at the base.

Common measuring mistakes

When to get a professional measure instead

For anything other than a straightforward like-for-like replacement — a new build, an unusual opening shape, very limited headroom or side room, or where automation is planned — a professional survey measure is worth having before ordering, since an installer will check headroom and side room requirements against the specific door and gear being quoted, not just the opening size. Most UK installers include a measuring visit as part of the quotation process for exactly this reason.

Monthly: visual and functional checks (owner)

• Look for visible wear, fraying or rust on cables, and any obvious slack or damage on either side of the door.
• Check the door opens and closes smoothly without jerking, grinding or hesitating partway through its travel.
• Test the safety reversal function on an electric door by placing an object in the door's path during closing to confirm it stops and reverses.
• Wipe the photocell lenses (if fitted) with a soft cloth — dirty or misaligned photocells are one of the most common causes of a door that won't close.
• Listen for new or unusual noises — grinding, squealing or banging — which often indicate a developing fault worth investigating before it becomes a breakdown.

Six-monthly: lubrication and hardware (owner, with care)

• Lubricate rollers, hinges and tracks with a suitable garage door lubricant — not general-purpose oil, which can attract dust and grime.
• Check and tighten visible nuts, bolts and brackets that have worked loose, without adjusting anything related to spring tension.
• Clean tracks of debris and check they remain straight and free of dents or obstruction along their length.
• Inspect weather seals around the door edge for perishing or gaps and replace if compromised.

Annual: professional service (engineer)

An annual professional service, typically £80–£150 in the UK, covers the checks and adjustments that should not be attempted without training — spring tension, cable condition and correct winding, operator force and limit settings, and a full safety-system test against the requirements of BS EN 12453. Many manufacturers' warranties are conditional on evidence of regular servicing, so keeping a record of annual services protects any warranty claim later.

Never attempt to adjust, tension or replace a garage door spring yourself. Springs store enough energy to cause serious injury, and correct winding requires the right bars and technique — this is always an engineer's job.

What warrants calling an engineer outside the annual service

Log books and BS EN 12635

BS EN 12635 covers installation and use of power-operated doors and requires a log book recording installation details and subsequent maintenance for the door's working life. Keeping this log book up to date — including who serviced the door and when — is both good practice under PUWER 1998's duty to maintain work equipment and often a specific requirement for warranty validity. See the installer guide for what a compliant handover should include.

Why this happens: a very British problem

UK garage door manufacturing consolidated significantly through the 2000s and 2010s, with a number of well-known domestic brands closing or being absorbed into larger groups. Because up-and-over doors in particular were built to last for decades, it is common to find a door still perfectly serviceable structurally but fitted with gear from a brand that stopped producing exact-match spares many years ago. This is a distinctly UK situation — the specific brands, gear designs and spares ecosystems involved have no equivalent in US garage door content, which is written for entirely different door types and manufacturers.

Brands commonly found to be discontinued or hard to source

This is a general pattern rather than a complete or fixed list — spares availability changes over time, and the only way to know for certain whether a specific part is still available is to check directly with a current supplier or engineer who deals with legacy UK gear.

What "obsolete" actually means in practice

A part being obsolete does not usually mean the whole door needs replacing — it means the exact original component is no longer manufactured, so the practical options are a close-match universal replacement part, a reconditioned original part sourced second-hand, or replacing the gear mechanism entirely with a modern equivalent. Cardale's spring drum units are a specific and common example: the drum unit itself is obsolete, but the door can typically be upgraded via a modern canopy gear conversion rather than being scrapped, which keeps the original door panel in service on new, currently-supported gear.

Universal and compatible parts

Where an exact brand-match spare cannot be found, many components — rollers, cables, hinges, and in some cases springs matched by measurement rather than part number — have universal or compatible equivalents that fit a wide range of older UK doors regardless of original brand. This route needs the gear type (canopy or retractable — see the identification guide) and accurate measurements rather than a brand name, since the original brand name alone is often not enough to source a working replacement once the exact part is discontinued.

When to consider a full gear conversion or replacement door

If repeated obsolete-parts issues are turning into a pattern on the same door, or if a key structural component like a spring drum unit is unavailable and no universal equivalent exists, a full gear conversion (keeping the existing door panel on new gear) or a full door replacement becomes the more realistic route rather than an increasingly difficult hunt for original spares. An engineer experienced with legacy UK brands can usually assess quickly which of these applies to a specific door.

What DHF registration means

DHF (Door and Hardware Federation) is a UK trade association for the door, gate, hardware and industrial door sectors. A DHF-registered installer has joined this trade body, which is a reasonable indicator of trade engagement and access to industry technical guidance, but registration with a trade association is different from a product being certified to a specific standard like PAS 24 — the two are not interchangeable, and a DHF-registered installer should still be able to point to product-level certification for security-rated doors specifically (see the security standards guide).

Questions worth asking before booking

• Is the price quoted the full installed total inclusive of VAT, or will parts, delivery or old-door removal be added separately? Under the DMCC Act 2024, an "invitation to purchase" should show the total price including mandatory charges — a genuine "from £X" figure should be one that is actually achievable.
• What is the exact door make and model being quoted, and can you see the manufacturer's specification, including U-value if insulation matters to you?
• If the door is electric, what operator is being fitted and what is its force/torque rating (see the motor sizing guide) — will they confirm it is correctly matched to the door?
• If security certification matters to you, which specific standard (PAS 24, TS 007, LPS 1175) does the product itself carry, and can they show the manufacturer's certificate?
• Will you receive a BS EN 12635 log book at handover, and what does the warranty require in terms of ongoing servicing?
• What is covered by warranty, for how long, and is it conditional on annual servicing (see the maintenance schedule guide)?

What a compliant written quote should include

Handover: the BS EN 12635 log book

BS EN 12635 requires power-operated doors to be supplied with a log book recording installation details, to be updated with each subsequent service through the door's working life. At handover, a compliant installer should provide this log book, or confirm clearly how installation records will be kept if a physical book is not used. Keeping this record is not just a compliance formality — it is frequently a specific condition of the manufacturer's warranty, and it is the document an engineer will want to see at the first annual service.

Red flags worth being cautious about

• A quote given only as a bare "from £X" figure with no breakdown of what is and isn't included.
• An installer claiming their business itself "is" PAS 24 or Secured by Design accredited, rather than pointing to a specific certified product.
• No mention of a log book or servicing record at handover on an electric door.
• Reluctance to confirm the operator's force/torque rating or how it was matched to the door.
• Pressure to sign on the day with no time to compare against a second quote.