Heritage aluminium doors offer you an authentic, classic aesthetic, reminiscent of iconic Crittall styling.
Glazed doors with astragal bars and slim sightlines let light flood in and give a crisp, contemporary look that can be equally suited to both internal and external doors.
When deciding on the right design for your heritage glass doors, it’s easy to focus on the more obvious decisions such as colour, glazing style and hardware. However, one detail that can have a surprisingly significant impact on the appearance of your doors is the positioning of the lock box.

For glazed, Heritage aluminium doors, there are two main options: a floating lock box or lock stile. Both fundamentally achieve the same function but differ in how they’re integrated into the door, which significantly influences the aesthetic.

A floating lock box is a standalone section of framework that houses the lock mechanism. It ‘floats’ within the glazed design, usually aligning with the horizontal glazing bars.
A floating lock box creates a more minimalist appearance by reducing the amount of visible framework and maximising the glazed area.

A lock stile incorporates the lock box within a full-height vertical stile running from the top to the bottom of the door. This creates a continuous section of framework on the locking side of the door.
Whilst this introduces more visible framework than a floating lock box, a lock stile offers specific structural and security benefits.
| Feature | Floating lock box | Lock stile |
|---|---|---|
| Glazed area | Maximises glazing | Slightly less glazing |
| Aesthetic style | Minimalist, contemporary | More traditional, substantial |
| Security | Standard | Enhanced resistance to forced entry |
| Additional locking points | No | Yes |
| Astragal bar options | Can accommodate more substantial astragal bars | Allows slimmer astragal bars |
Does the lock box position affect security?
Yes. A lock stile provides greater resistance to forced entry and allows additional locking mechanisms to be fitted at the top and bottom of the door, making it the preferred option for external heritage doors.
Is one option more authentic for heritage doors?
Both options can work equally well for heritage-style doors. Your decision will depend on the overall aesthetic you’d like to achieve, as well as the practical requirements of each door.
Does the choice affect the glazing bars?
Yes. A floating lock box can accommodate more substantial astragal bars if that’s the desired look, whilst a lock stile can enable slightly slimmer bars.
If your goal is to maximise the glass area and achieve a contemporary, minimalist appearance, a floating lock box is an excellent choice.
Choose a lock stile if security is a higher priority, particularly for external doors. The additional strength and ability to include multi-point locking will give you the required reassurance, without compromising the character of a heritage-style design.
We can advise you on the best option for each door, plus it’s possible to have both styles within your home depending on the situation of each of your new doors.
Please call us on 01444 45 71 45 or visit our Haywards Heath showroom for more information about our Heritage aluminium doors.