What is the Sarking and why is it so important for your roof?

Dear readers, As promised last week, this week I am going to talk to you about the sarking.

The other day, I was surfing on the Internet and I have read a lot of blogs saying that the sarking is not so important for your roof, and you could either avoid to install it.

This sounded so wrong to me!!

What is the sarking and why is it so important?

As Sarking (or underlay), I refer to the waterproof membrane put under the battens of the roof.


It is very important, because helps in regulating the temperature of the house, and to protect it from insects and wind. Without a good sarking, the roof would become moldy, and your tiles will look dirty green.

Moreover, also your ceiling and your wall will look moldy, and this is something really not nice to see!

Of course, when choosing your Sarking, you should first look at the features of it, because not all of them are the same, but there are lots of different types on the market.

The most important characteristics that a good sarking should have are:

  • Strenght: the sarking membrane has to be strong. There are some sarkings on the market that break just applying some pressure on them with a finger.

A sarking like that will have to be changed in few years time, and would be very costly.

The sarking is the underlay of the roof, and a strong roof needs a strong sarking.

Pay attention to that.

  • Heat Protection: the sarking must be breathable. This means that must allow the vapor from the heating to get outside, but at the same time protect from cold/heat from outside.
  • Water resistant: must be waterproof, and not letting the water come inside when it rains.  The sarking, indeed, can be considered as part of the insulation system of the roof, therefore must not let the water in.
  • UV resistant: a good sarking must have good UV resistance properties. Must not be ruined but these rays: this is an important quality, most of all in Australia where UV rays are so powerful!!
  • Fire resistance: some sarkings are more resistance to the fire, other less. Check the fire resistance of the sarking before buying it, especially if you live in a high risk of fire area. Australian fire resistance scale is different from the European one, so try not to get confused: the minimum requirement for the Australian sarking is level 5.
sarking foils

..So guys, all the roof is important: keep it in mind when you build it! I hope these information will help you to understand how important the sarking is :D!