How big can you go?


Exploring Window and Door Size Possibilities in the UK: Guidelines and Limits

Demysifying standard parameters and guidelines for window and door sizes in the UK, based on Building Regulations compliance. While there are no "standard" sizes, there are weight limits for window sashes. We provide specific size details for different window and door styles, including bifolds, sliders, French doors, and front doors. 

Window and door openings in the UK tend to largely fall within certain standard parameters in order to comply with the Building Regs which set minimum dimensions to comply with things like fire escape rules and disabled access. 

But, just as there’s no such thing as a standard sized house, there’s no such thing as a standard sized window and door either. That doesn’t mean to say there aren’t some useful guidelines (and limits) you need to be aware of though.


The maximum size of an aluminium window is generally dictated by the weight of the sash rather than the dimensions – hence the fact that fixed light windows can often be bigger than ones with opening lights. For our 58BW casement window system, for example, the maximum weight is 250kg for a fixed light, 180kg if it opens at the bottom, 60kg if it opens at the top and 55kg if it opens at the side.

Other window styles and configurations have different limits though, and we have all the details on our product pages here. 



For our F82 Plus and BSF70 HI bifolds, you can have anything from 2 to 7 panels in your doors – each up to 1200mm wide and up to 3000mm high.


For our BSC94 inline and lift and slide patios, each of the glazed panels can be up to 2000mm wide and up to 3000mm high, and our SC156 system gives you even bigger options – with each panel up to 2700m wide and 3100mm high.

French doors

Open or open out French doors in our 58BD HI system, can be up to 2400mm wide (1200mm each door) and 2400mm high.

Front doors 

Our 58BD HI residential front doors have the same maximum dimensions as the French doors at 1200mm wide and 2400mm high, but if you want something bigger, then you can go to 1250mm and 3100mm high in our 77ID range. 


Of course, new and replacement windows and doors are always made to measure because no two properties are the same, and a perfectly measured and perfectly installed window and door will guarantee you optimum energy performance and security.

We can help you find an authorised AluK dealer in your area who can give you all the help and advice you need. Just get in touch with us here.