Measuring Roller Garage Doors

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Roller Garage Door Measuring Guide

Measuring for Roller Doors

Roller Garage Doors manufactured and sold in the UK are split into 2 distinct categories - Insulated, double skinned aluminium roller doors and non insulated single skin steel roller doors.

When measuring for either door the dimensions required are the same initially. Carefully measure your aperture, taking width measurements at the top, middle and bottom and then across the width at various points from floor to underside of lintel or ceiling if you have no headroom or lintel showing. Measure the reveal depth and returns inside (the width of the brickwork as you look from inside out on either side of the opening) then measure the headroom available, the height above the opening as looking from the inside again. Ideally and in most cases the back of the piers will line up with the back of the lintel so you have a flat face to fit to as you stand inside your garage looking outwards.

Your biggest factor in how you order and work out the ordering dimensions depends on whether you are installing the door INBETWEEN or BEHIND the structural opening, or sometimes even a mixture of both.

GDO Roll 77 Behind fit     GDO Roller Door Face Fit

     Seceuroglide roller door installed inbetween garage opening


Insulated Aluminium Roller Garage Doors

Insulated roller doorThis is now one of the most popular types of electric garage door in the UK and one reason might well be that you can install this door inside (face fit internal), inbetween (reveal fit), or even outside (face fit external) your garage opening. 

Width - The design of this type of door means the width is the same all the way from bottom to top as the endplates at the top sit in line with the outer edges of the guides either side, so there is nothing sticking out to worry about when installing inbetween.

Height - The height is determined by the ‘Guide Height’ plus the endplate sizes, these endplates are the fixing plates for the optional hood covers offered with many brands. The overall measurements are the most important dimensions of you are fitting INBETWEEN your structural opening.


Single Skin, Continuous Steel Curtain Roller Garage Doors


Basic Single Skin Steel Roller Door

This is a roller door which has been sold now since the 1980’s in this country, originating from Australia. It is a simple design, a continuous sheet of profiled steel for the curtain, which rolls around a skeleton barrel system. It has a larger roll size than the aluminium individual slat roller doors. This type of door is great value for money, but offers little performance in terms of insulation or security. It is perfect for many applications.

This roller door type can only fit BEHIND a structural opening or framework and does have additional space required on either side of the guides for the steel fixing lugs and also steel tubing sticking out from the barrel at either end, not in line with the side guides. This roller door is quite forgiving when installing, if you have slightly out of level walls.

Insulated Roller Door Dimension References

Dimension references for most Insulated Aluminium Insulated Roller Doors, which include:



GDO Logo
GDO Roll 55 and Roll77

Insulated Roller Door Front View

The Hormann and Garador insulated aluminium roller doors are ordered differently. This is however only the WIDTH reference, which for these brands is the width inbetween the guides.

The Ordering width is the width between the guides so make sure you take account of the guides either side and their dimensions.

A full hood cover is also a standard feature on the Hormann and Garador insulated roller doors.

Visit our online shop for insulated roller doors


Visit our online shop for Hormann insulated roller doors

Steel Continuous Curtain Roller Garage Doors (Gliderol Series A, AA and Mini Roll)

These steel single skin roller doors are ordered by the actual overall guide width, but without taking into consideration the fixing lug dimensions. The ordering height is the same as other roller doors, the guide height, or stop height and you have to take into account the curtain roll size above these guides.

REMINDER : These roller doors can ONLY fit BEHIND an opening or frame.

Also note you can order these roller doors wider than the opening width plus the guides, if you have any doubts about your brickwork or blockwork, or if you want to use a standard width door. As long as you can accommodate the curtain, guides and lugs the actual daylight opening isn’t that relevant. So for example if you have a 7’4” wide opening but have 200mm plus either side internally you could order the standard door for a 7’6” opening which is 7’8” with the guides.
The curtain will simply overlap an extra 25mm either side.
Steel Continuous Roller Curtain Front View Steel Continuous Curtain Rear View


Visit our online shop for Gliderol continuous curtain doors

More Explanation:

Measuring and Ordering an Aluminium Insulated Roller Garage Door

Measuring for an insulated roller door depends on the desired location of the door, as this can impact the exact dimensions required. These doors are typically ordered using the overall width (Over Guide Width), including the guides which differ in size between manufacturers. As a result, the overall ordering width may change depending on your choice of manufacturer. For example, the Hormann Rollmatic and Garador GaraRoll will have different ordering sizes for the same sized opening, and are likely to be different to most other manufacturers.   
1.  Measure the Width of your opening from the top to bottom in several places
2.  Measure the Height of your opening from the underside of the lintel to the floor in several places across
3.  Measure the inside faces either side of the opening
4.  Measure the headroom inside available


Door Ordering References:

Fitting BEHIND

Structural Width (widest dimension) + 2 x appropriate guide width, depending on exact door brand and model = Door Ordering Width
Height from floor to underside of lintel (largest dimension) = Door Ordering Height

This is if you are fitting behind the opening. If you intend to fit in between the opening see below.


1.  Structural Width (smallest dimension) less fitting tolerance, usually allow about 10-20mm = Door Ordering Width
2.  Take the smallest Height from floor to underside of lintel or ceiling minus the endplate and hood size and less some fitting tolerance = Door Ordering Height

If you don’t have sufficient headroom to fully accommodate the endplates and curtain roll then simply work out your total height available less the endplate size and this gives you the guide height for ordering anyway.

Not having enough headroom does not prevent you from having a roller garage door, just focus on the final drive through height and make sure you are happy with this height.

Please also refer to the 'measuring tab' section shown in the online shop products before placing an order.


Measuring and Ordering a Steel Continuous Curtain Roller Garage Door

Gliderol Single Skin Roller DoorIt is important to note that when measuring for the steel single-skin curtain Roller Garage Doors they can only be fitted BEHIND the opening, unless a timber or steel frame is fitted, enabling the guides and supports to face fit internally.

Measure the structural opening in the same way as any other door, ensuring sufficient side and headroom has been considered for the chosen model and size of steel roller door. 

Take the largest clear daylight opening dimensions and add the guide size (curtain overlap) for each side. This gives you the ordering width.

Door Ordering References:
1.  Structural Width + 50mm (Gliderol Single Steel Roller Door) OR + 100mm (Gliderol Double Steel Roller Door) = Door Ordering Width
2.  Height - The guide height required, i.e. ideally the height of the underside of the RSJ/lintel opening = Door Ordering Height

The ordering width does NOT take into account the overhang on either side for the fixing lugs or support brackets. Unlike aluminium roller doors, the ordering width is not the overall width for the installation (please check the measuring tab in the shop). 
Example: For a structural opening measured as 2400mm wide and 2150mm high, the Ordering Size is going to be 2450mm width and 2150mm height.
The ordering height is simply the 'guide height', the height between the floor and the underside of the lintel. If you don't have the internal height for the roll size you can simply reduce the ordering height or cut the tracks before installing.

Every roller garage door will have a small section of the curtain hanging down slightly when fully open, usually about 50mm, so if you do require the full drive through height when the door is open and you have sufficient headroom, then add on another 50mm or more to the ordering height to take the door curtain higher internally.

Please also refer to the 'measuring tab' shown in the online shop when placing an order.

Additional information

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