How to measure for a Weather Louvre

When deciding which louvre size will fit. You will need to follow a few simple steps to ensure it is correct:

Square Weather Louvres

1. You will need to measure the actual opening hole size you want the Louvre to sit in.

2. For example if the opening is actually 500mm width x 500mm height, then you would need to order the 500mm Weather Louvre. 

3. The overall size of the Weather Louvre will actually be 545mm width x 545mm height, as a 28.5mm flange is added all away around, to ensure it covers the opening. The Louvre is also made to be 12mm smaller than the actual opening size to allow it to slide perfectly within the opening, so not cause any friction.

Made to order Weather Louvres

In some instances the opening may not be a perfect square. In this scenario you would need a made to order Weather Louvres.


1.Measure the actual hole size

You will need to measure the actual hole size that you will want the louvre to fit inside. Width and height in mm. From these dimensions we can then calculate the actual neck size. Which is usually 12mm less all the way around

2.Production of the Weather Louvre

In production, we will then add the extra flange of the louvre to fit comfortably within the hole. Usually this is 38mm all the way round, but can go up to 1000mm

View our handy weather louvre measuring guide