Roofing felt is one of the most prominent building materials on a roof. There is a wide range of manufacturers, thicknesses and benefits to each type of felt. However, just because a felt is thicker doesn’t mean it’s the best for your job — money-wise and quality-wise. In this short guide, we’ll look at different thicknesses of roofing felt and explain which one you may want to use.
Non-breathable felt thickness
With non-breather felt, such as Cromar’s Protect 1F, you’ll get 0.5mm in thickness. This type of felt is classed as secondary and provides temporary protection (around three months) if installed correctly. The advantages of this felt is that its easy-to-use, lightweight and has fantastic nail tear resistance.
95gsm Thickness Breather Membranes
If you’re looking for a breather membrane such as the popular Cromar Vent 3 Light, then you’ll be getting 95gsm of thickness. This is a good starter product for cold and warm roof applications and has terrific benefits over traditional roof underlays, such as its cost and weight.
115gsm Breather Membranes
The Vent 3 Classic is a solid upgrade to the Vent 3 light. Unlike the Light, the Classic has 115gsm of thickness, producing a more robust performance for your roof. Like the Light, it is suitable for warm and cold roof applications.
135gsm Breather Membranes
For higher performance, you might be looking at Vent 3 Blue, simply known as Cromar Vent 3 roofing felt. The thickness of the felt is 135gsm and has major benefits for serious roofing projects. It comes in various sizes, including 25m and 50m.
How thick should felt be for my roof?
All roofs are different. Thus, we suggest asking a professional’s opinion on the type of felt and thickness you need. A well-experienced roofer who can inspect and make recommendations on the roof felt you require for your home or DIY project. We would only recommend going ahead with a purchase if you have a plan. Discuss it with a roofer and buy accordingly.
