What is fibreglass matting

What is fibreglass matting, where does it come from and what type do you need to put on your flat roof.

Fibreglass, also known as chopped strand mat, CSM, glass-fibre or just plain old mat or matting is a reinforcement made up of fibreglass strands that are randomly oriented and typically held together with a styrene-soluble binder that acts like glue connecting the fibres.

The binder is the secret recipe to the matting and will vary from manufacturer to manufacturer giving the chopped strand mat different properties. The binder dissolves upon contact with styrene in the fibreglass roofing base resin allowing the the matting to soften, making it easy to work with and mould around existing roof furniture.

While it’s not as strong as carbon fibre for example, it’s less brittle and much easier on the bank account. Over the years fibreglass has proven itself to be the strong lightweight material of choice for many industry sectors including aerospace, marine, automotive, bath tubs and enclosures, swimming pools, water tanks, pipes, cladding, casts, surfboards and of course roofing.

Lloyds Approval

Fibreglass roofing comes from processes developed in the marine industry and you might have noticed that some products are Lloyds Approved, in fact all of the Fibrelast resins, topcoats and fibreglass matting we supply is Lloyds Approved, but what does it mean and whats so special about it?

The Lloyd’s Register Group Limited is a technical and business services organisation owned by the Lloyd’s Register Foundation, a UK charity dedicated to research and education in science and engineering. The organisation which dates back to 1760 helps its clients (by validation, certification and accreditation) to ensure the quality construction, and operation, of critical infrastructure.

An approval from Lloyds demonstrates that your product conforms to recognised industry quality standards, International Conventions and/or the LR Rules, through a process of independent design review, extensive sample testing and verification of production controls.

What’s the best weight for GRP roofing?

Fibreglass matting is sold in many different weights. 100gm and 225gm mats are more commonly used in other liquid roofing systems, like Fibrecoat where only a light reinforcement is needed. For standard GRP roofing systems like Fibrelast 450gm and 600gm matting are the only two weights you’ll need to worry about.

Depending on who you talk to, people will recommend different weights of matting to use on a roof, some people say you could get away with 300gm and some roofers will stick with a single layer of 450gm which cuts down on the amount of base resin used but could compromise the roof in the longterm.

The type of fibreglass to use on a roof needs to be determined by surface area and foot traffic. Our recommendation and guidelines for Fibrelast installation is that the only time you use 1 layer of 450gm is on roofs up to 5 square metres. For everything else its either 1 layer of 600gm or a dual layer of 450gm for foot traffic. For more information on the subject including our surface guide check out the fibreglass matting section of our online guide.