Accurately Measuring For Your Steel Door

Structural Opening Size What is the ‘structural opening size’?

The structural opening size refers to the inside measurements of your aperture/opening. Within the industry you may hear the terms ‘brick to brick’ or ‘block to block’, however, the correct terminology is structural opening. Unlike frame/made sizes which will already include a deducted tolerance, the structural opening size is the exact measurements you take of the opening.

How do I measure the structural opening for a Strongdor door?

When sizing up your door you should always measure the width and height from at least 3 different points within the aperture. Sometimes you may find your structural opening is not perfectly square. The width at the top and bottom may differ slightly, or the height may vary from one side to another. If this is the case, you should quote the smallest measurements. If there is a significant difference, please inform the sales team when requesting a quote. At Strongdor, we will take your structural opening size and remove the tolerance in house. When requesting a quotation from us, you must always state the structural opening size only and never take the tolerance off yourself.

What do I measure if I’m replacing an existing door?

When replacing an existing door, you must always request a quotation using the structural opening size only. You should never use the measurements of the existing door that is already installed as this is not an accurate and reliable measurement. If the previous door you are replacing is a Strongdor door, you can provide the ‘SN’ (serial number) to our sales team who will be able to advise the previous sizing, you can locate this in the jamb of the door.

What metric should I measure my structural opening in?

Prior to requesting a quotation from us, we always advice that you measure your structural opening in millimetres. Using a smaller metric will allow for the most accurate measurement reading.

Access this document in the Strongdor Knowledge Library here: Accurately Measuring For Your Steel Door