Fibreglass, a material widely used throughout the UK and Ireland as a convenient way to build flat roof garage extensions.

Why choose fibreglass for a garage roof?

Often recommended for its non-corroding properties, fibreglass is an inert material which makes it perfect for the unpredictable climate that the UK and Ireland often experience. Fibreglass will last through hail, rain, sunshine and snow. Applying materials correctly will ensure the roof will last in excess of 20 years. If in doubt of how to apply fibreglass roofing materials, our installation guidelines provide some top tips.

A fibreglass garage roof will always have a watertight finish which consists of 3 layers;

  • OSB3 Board - Plywood or similar may be used but OSB3 Board is recommended
  • Fibreglass  - Once resin has been applied to the fibreglass mat, the mat becomes rigid, giving toughness to the roof
  • Topcoat – The final stage of the flat roof, adds colour and a tack-free finish

A typical double garage in the UK or Ireland will measure approximately 12sqm. This area is perfectly suitable for a fibreglass build as fibreglass is suitable for almost any sized roofing development. Furthermore, it works equally well for commercial and domestic roofing projects. 

GRP roofing trims give the garage roof a decorative and professional finish. Moreover, roofing trims ensure the roof gets adequate drainage which is an important requirement for any roofing project. Edge roofing trims are applied prior to the lamination phase (application of the fibreglass mat and resin) therefore, the overall aesthetics of the garage roof are not impacted and the roof remains seamless.

How much fibreglass is needed for a garage roof?

FibreGlassDirect offers a fibreglass materials calculator, providing an easy way to work out the quantities needed for a garage roof. Links direct to the products needed are also provided in the calculator making it easy to get a shopping list together.

Alternatively, comprehensive fibreglass roofing kits are also available as part of the product offerings on FibreGlassDirect.

Fibreglass Roof Calculator

Fibreglass Garage Roof Kits

Roofing kits are available in 2 formats – Premium and Standard. Both roofing kits are specifically formulated for fibreglass roofing projects therefore the requirement of either depends on the specifics of the fibreglass garage project.

Fire-retardant topcoat is provided as part of the premium fibreglass roofing kit (in both 450g and 600g options), making it the obvious choice where increased fire-resistance is required. For example, if the garage is attached to a domestic property or highly flammable materials are stored in the garage. In addition, the premium kit also provides a flexible roofing resin which aids slight movement in the roof during natural contractions and expansions.

Premium roof kits are available in 1 layer of 450g or 600g options. The difference in glass weight is dependant on the amount of foot traffic which will be on the roof. For example, if there will be little to no foot traffic (as we see with the majority of our roofs) then 450g will be sufficient. For roof cases where there may be moderate footfall, a 600g option would be more suitable. 

Standard roofing kits may be a suitable choice if unlike the above; the garage is a stand-alone building with no flammable liquids in store and increased fire resistance is not a requirement. These kits will provide a Lloyds Approved Resin and a Standard roofing topcoat.

The most popular roofing kit we supply for fibreglass garage roofing is the 15sqm roofing kit 

Fibreglass Roofing Kits