How Do I Measure My Fascias And Cover Boards?

With so many different types of fascia boards now available on the market, it’s important to know what each of the various measurements mean, how to take them and what measurements to take on your property to ensure you are purchasing the correct size of board.

We’ve created this quick video that demonstrates exactly how we measure PVC fascia boards, featuring close-up shots to explain the exact dimensions. Below the video, we go into more detail on these measurements, including information on what measurements you should take on your property.

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Measuring Fascia Boards

Our diagram below shows all of the important fascia measurements and where they should be taken from. It also shows the front, back and cross section of a standard 18mm fascia board.

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A. Board Thickness

Arguably the most important measurement, fascia boards come in many different thicknesses, even differing from one manufacturer to another.

Generally, PVC fascia boards have a thickness of 16mm-18mm. The freefoam boards that we stock are 18mm thick. This thickness makes them suitable for either fully replacing old timber fascias on their own, or for being used on new builds without a timber backing board. 

This is why you will often hear these boards referred to as replacement fascias, which is still accurate. However, since they are often used on new properties where the timber fascias are forgone altogether, they aren’t always ‘replacing’ anymore.

The only exception to this rule is capping boards, which are boards that have the same profile as regular fascias, but they are much slimmer at only 10mm thick. These boards are designed to cap-over (hence the name) old timber fascias that are still structurally sound, and their smaller size makes them slightly cheaper.

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B. Board Width

Fascia board widths will vary, much more so than thicknesses. We offer PVC fascia boards with widths ranging from 150mm all the way up to 300mm in most colours, as well as 404mm wide boards that are used to construct a fascia box end.

Our most popular widths are in the 150mm-200mm range which are widths that will suit most domestic properties; however we offer larger sizes for commercial properties or specialist projects.

The width of the board that you should choose depends on the height of the rafter ends on the edge of your property.

If you are replacing old timber fascias, you can just measure the measure the width of the timber board that is currently in place and choose a PVC board that matches that measurement.

On a new build however, you’d need to measure the height of the rafter ends and ensure that you choose a fascia board with a large enough width to cover them.

If you are going to be covering existing timber fascias with PVC capping boards, you should keep in mind that you’ll need to subtract 10mm (the thickness of the board) from the board's width in order to calculate how much of the old timber board the PVC board will cover.

This is due to the 10mm thick return leg sliding underneath the timber board. You’ll also need to leave a space between the top of the return leg and the bottom of the timber fascia board in order for a 10mm thick soffit board to be fitted.

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C. Return Leg

The return leg measurement is the distance between the front of the fascia board and the end of the return leg. On both our 18mm and 10mm thick Freefoam boards, this measurement is 40mm.

This measurement itself doesn’t need to influence your purchasing decision from one board to another since it will be the same, but it should be noted that the groove above the return leg on the inside of 18mm thick boards is where the soffit boards will be fitted.

The 10mm thick capping boards don’t have this groove, instead the soffit board is fitted in the gap you leave between the top of the return leg and the bottom of the timber fascias.

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D. Board Length

All of our fascia boards are available in five metre lengths, so after you have chosen the width and thickness of board that is most suitable for your project, you’ll need to calculate the total length of roofline that needs to be covered by fascia, and ensure that you purchase enough boards.

For example, if the total length of your roofline that needs replacing or covering is 28 metres, you’ll need to purchase six boards of five metres.

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We hope that this article has assisted you with your project, but if you have any questions regarding measuring fascia or quantities of boards and trims that you might need, please don’t hesitate to get in contact with our team of experts.