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Step by Step Guide for Working out Fence Materials

Step by Step Guide for Working out Fence Materials

Posted by Lisa Taylor on 13th May 2022

Are you looking to build your own fence but aren’t sure what materials you need?

There is nothing better than the feeling of creating something from scratch, which is why a lot of our customers buy wood materials from us to construct their own fence. While a lot of people have the manual dexterity to erect a fence with ease, often it can be hard for some to work out how much material needed for the job. At first it does seem daunting, but it doesn’t have to be!

What length of fence do you need?

Work out how long the fence needs to be in metres, taking into account any gaps for gates. Let’s look at an 11 metre long fence, that’s 6 foot high. An 11 metres fence is 1100 cm, or 11000 mm. First you need to work out how many slats you need to fill the 11 metres. Choose the ideal width of slat for your fence and add on the size of the spacing you would like to have between the slats. There is no correct spacing size, however lots of people choose to make the gap the same size as the depth of the slat. So, if you choose a slat that is 100 mm (4 inches) wide and 20 mm deep you simply add on another 20 mm to give you one segment of 120 mm. A segment here is the width of the slat plus the desired gap.

Using the same term of measurement, we can work out how many slats are required:

11000 mm ÷ 120 mm = 91.66

You should err on the side of caution and order an extra couple of slats, just in case you need them. It is better to have them on hand than stop mid project

Work out the number of posts required

Determine how many fence posts you will need. A fence post will be required at the start and end of the fence and at every corner. On top of that, a post will be required at regular intervals to give the fence stability, around 1.8 metres (6 feet) is ample. Keep in mind that fence posts need to be biggerthan your slats as around 1/3 of the post will be buried; so for a 6 foot high fence, 8 foot posts are needed . 11 ÷ 1.8 = 6.11. We round this up to 7 and add an extra one in for the end, so we would need 8 posts.

Fence rails come in a number of different lengths, however the most common lengths are 3.6 metres and 4.2 metres.

The next step is to work out how many rails are required for the backing. Sometimes rails are referred to as straps or strapping. To do this we divide the total width of the fence by the length of the rails.

11 m ÷ 4.2 = 2.61 rails per row. This should be rounded up to give you a whole number. Most fences with vertical slats have 3 rows of rails, so multiply your new amount by 3 – giving you 9 rails. If you only want to have two rows of rails, you would multiply it by two instead.

It’s easy once you know what to do

Once you know the numbers that you need to find out it is not too difficult to work out the quantity required. In this example we worked out how many slats, posts and rails are required for our 11 metre long, 6 foot high fence.

Slats – 1.8 x 19 x 100 mm = 92 (plus a couple extra if desired)

Rails – 4.2 x 75 x 38 = 9

Posts – 2.4 x 100 x 100 = 7

Post Crete is a form of concrete that is used to set the posts into the ground. Another option is to use a bolt down met post to secure the post into existing concrete, or use a spiked met post inserted into the ground to support the new posts.

Whatever option you choose, you will need one per post. Sometimes you can use one bag of postcrete for 2 posts,  this is entirely up to you.