How Do I Measure My Door Structural Opening?

When measuring your door size, there are three critical measurements you need to be aware of.

First is the structural opening, this is the actual size of the opening in the wall typically measured from brick to brick, and floor to lentil without any tolerances removed. It’s important that this opening is larger than the external frame size by at least 10 mm in width and 5 mm in height, to allow for fitting tolerances.

Then there is the external frame size, which is the size that our steel door frames are made to when manufactured as per the customer order.

Finally, there’s the clear opening. This is calculated by taking the external frame size and subtracting 110 mm from the width and 55 mm from the height.

By understanding these measurements, you can ensure a perfect fit for your new door.

For more information and advice on door sizes and openings, go to our website.