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A double garage is the one place where a roller door really earns its keep. There is no swing-out, no tracks under the ceiling, and the whole opening is clear the moment the curtain is up. The catch is that a wide opening asks more of the door: a longer curtain, a heavier barrel, a stronger motor and more headroom for the top box. This guide covers the sizes you are likely to be working with, whether to fit one wide door or two singles, and which TWF door fits which opening.
Everything below applies to the doors we build to measure in our Norfolk workshop and deliver nationwide as DIY kits, or fit ourselves across Norfolk and Suffolk. If you already have your measurements, the Garage Door Builder will tell you in a minute which range your opening falls into.
What counts as a double garage door in the UK?
There is no single official size. Older UK homes were often built with a 14ft opening, which is about 4267mm, and many newer homes have 16ft, about 4877mm. Plenty sit somewhere between, and a converted pair of singles can be any width at all once the central pier has gone. What matters is the opening you actually have: the width brick to brick at the top and at the bottom, the height from the finished floor to the underside of the lintel, and the clear space above and to each side.
Measure in millimetres from inside the garage looking out, and use the smallest figure wherever the opening varies. Our measuring guide walks through the six measurements with a video, and the builder takes those figures directly. A roller door cannot be made larger once it has been manufactured, so this is the step to take slowly.
One wide door or two single doors?
If your garage still has a brick pier in the middle, the simplest answer is two single doors. Each opening gets its own made-to-measure curtain, motor and controls, and if one door ever has a fault the other still works. Two singles also keep each curtain in the 55mm range, which means a smaller top box, less headroom needed and a lighter kit to lift.
If there is no pier, or you are planning to remove one, a single wide roller door is the neater result: one clean curtain, one remote and the full width of the garage to drive into. Removing a pier is structural work that needs a new lintel across the whole span, so read our guide to converting two garage doors into one before you order anything, and have a builder confirm the lintel.
- Two singles: pier stays, two 55mm doors, two motors, independent operation, two remotes to keep track of.
- One double: pier removed, one Classic 77 curtain, one motor, one set of controls, a cleaner frontage.
A quick way to decide: two singles when the pier stays, one Classic 77 when it goes.
Why double doors use 77mm slats
Roller curtains are described by the height of each slat. Our Standard 55 and Premium 55 doors use a 55mm slat and are built for single garages, up to 2500mm and 2650mm wide respectively including the guide runners. Across a double opening a 55mm curtain would flex and rattle, so the Classic 77 uses a taller, deeper 77mm by 18mm insulated slat that stays flat and stable across spans up to 4950mm including the guides.
The larger slat also makes a larger roll, which is why the Classic 77 has a 300mm top box rather than the 205mm or 250mm boxes of the 55mm doors. For the full picture of how the two slat sizes compare, our 55mm vs 77mm guide goes through it range by range.
| Door | Opening width, including guide runners | Height, including top box |
|---|---|---|
| Standard 55 | 1200mm to 2500mm | Up to 2400mm with a 205mm top box |
| Premium 55 | 1200mm to 2650mm | Up to 2550mm with a 250mm top box |
| Classic 77 | 1500mm to 4950mm | Up to 2600mm with a 300mm top box |
Headroom, side room and where the top box sits
Headroom is the measurement that catches most double garages out. The Classic 77 top box is 300mm deep, so a behind-lintel fit needs at least that much clear space above the lintel inside the garage. If a beam, the opener from the old door or a low ceiling gets in the way, the top box can sit below the lintel instead. That costs a little drive-through height but still gives a neat, colour matched finish from outside.
Side room matters as well. The guide runners sit on the pillars either side of the opening, and anything fixed to those pillars, such as pipes, meters or light switches, needs noting before you order. Steps four to six of the measuring guide cover the returns and the top clearance for exactly this reason.
Motors and controls on a wide door
A longer, heavier curtain needs a stronger tubular motor. The builder matches the motor to the door you specify, so you do not have to size it yourself; if you are curious about what the torque figures mean, our motor sizing guide explains them. Every TWF door is electric as standard and comes with a wall mounted key switch. Upgrade to remote operation and the kit also includes a receiver box with control buttons, two remotes and a safety edge system in hard wired or wireless form.
Every door also includes a manual override, so the curtain can be wound open or closed from inside the garage in a power cut. If the garage has no other way in, add the external manual override from our shop and you will never be locked out of a double garage with the car inside.
Insulation and security across a double opening
A double door is a large surface, so insulation and security matter more, not less. All three TWF ranges use insulated aluminium slats with a foam core, and the side guides and bottom seal are there to limit draughts across the full width. If the garage is attached to the house or used as a workshop, that difference is felt in the rooms above and beside it. Our insulated garage doors page explains the construction in more detail.
On security, a closed electric roller door is held by its motor, and an Autolock adds a mechanical lock that engages each time the curtain closes. Fit the TWF77 Autolock on a Classic 77 curtain and the TWF55 Autolock on the 55mm doors; on a wide door one each side is a small upgrade for the reassurance it gives.
Fitting a double: DIY kit or local installation
Classic 77 kits are supplied for self-fitting anywhere in mainland England and Wales, with installation guidance and after-order support. Because a 77mm curtain is heavier, we recommend at least two people, and two to four for the largest doors, mostly for lifting the barrel into place. Our installation tips post sets out the sequence, and the existing posts on how difficult a DIY fit really is suggest budgeting a full day for a single door, so allow longer for a double.
If you are in Norfolk or Suffolk and would rather hand it over, we fit doors ourselves. There is a free survey first, then a written quote, and every installed door carries a 5-year parts and labour warranty. Our garage door installation page explains the process from survey to handover.
How to order a double roller garage door
Take your six measurements, open the Garage Door Builder and enter them with your colour and control choices. The builder shows the price straight away. The range starts from £505 inc VAT for a Standard 55 single door in white with key switch controls, and moves into the Classic 77 range as the width goes up. Doors are made to order and usually delivered within 4 weeks, with delivery to mainland England and Wales charged at £65, which is worth knowing if you are planning around the pre-Christmas delivery deadline on the site.
FAQs
How wide can a double roller garage door be?
The TWF Classic 77 is built to measure for opening widths from 1500mm to 4950mm including the guide runners, which covers the common 14ft and 16ft double openings and most converted pairs of singles. Wider than that, or with a central pier still in place, the answer is two single doors.
Is it cheaper to fit one double door or two single doors?
It depends on the opening. Two singles mean two kits, two motors and two sets of controls, but each curtain stays in the 55mm range. One wide door is a single Classic 77 kit with one motor. Enter both options in the Garage Door Builder with your measurements and compare the two prices side by side.
Can I replace two up and over doors with one roller door?
Yes, once the central pier has been removed and a new lintel fitted across the full span. That is structural work for a builder, and it must be finished before the opening is measured for the new door. Our guide to converting two garage doors into one covers the sequence.
How much headroom does a double roller garage door need?
The Classic 77 uses a 300mm top box. For a behind-lintel fit you need at least that much clear space above the lintel inside the garage. Where the ceiling or a beam is in the way, the top box can sit below the lintel instead, which reduces the drive-through height slightly.
Are double roller garage doors insulated?
Yes. All three TWF ranges, Standard 55, Premium 55 and Classic 77, use insulated aluminium slats with a foam core, and the side guides and bottom seal are designed to limit draughts across the full width of the opening.
How many people does it take to fit a double roller garage door?
Because a 77mm curtain is heavier than a 55mm one, we recommend at least two people for a Classic 77 kit, and two to four for the largest doors. Most of that help is needed for lifting the barrel and curtain into position; the rest of the fit is a one or two person job.
Key takeaways
- Measure the opening you have, not the size the house was built to; 14ft and 16ft are starting points, not rules.
- Pier stays, two 55mm singles; pier goes, one Classic 77 up to 4950mm wide.
- Allow 300mm above the lintel for the Classic 77 top box, or plan a below-lintel fit.
- The builder sizes the motor and shows the price instantly; made to order, usually delivered within 4 weeks.
Conclusion
A double garage roller door is a straightforward choice once two questions are answered: is the pier staying, and how much room is there above the lintel? With those settled, the Classic 77 covers almost every double opening in the UK as a made-to-measure kit, and two 55mm singles cover the rest. Price your layout in the builder, check your figures against the six measuring steps, and if you are local, book a free survey and let us measure it for you.
Written by the TWF team, who have manufactured and fitted roller garage doors from Norfolk for over 25 years. Last updated: 9 October 2026.
