A Guide to Corrugated Roofing Sheets

Wednesday, 28 September 2022  |  Admin

Corrugated roofing sheets are one of our most popular products. One of the simplest products to install it’s hardly surprising that their popularity continues to grow. As corrugated roofing sheets overlap it is not necessary to join sheets with a glazing bars as you would for polycarbonate roofing sheets. They are also more cost effective than other roofing materials making them a great choice for a gazebo, carport or even a small lean to structure.

There are two main types of corrugated sheets that we currently supply in the UK. Corrugated roofing sheets and corrugated bitumen roofing sheets. Here we will explain the differences between each of these products and their main uses and advantages.

Corrugated PVC Roofing Sheets

Often referred to a plastic roofing sheets, corrugated roofing sheets are one of the most commonly used sheets in the UK. Being plastic they are strong, durable and extremely lightweight. The most popular corrugated PVC sheet is the 3” ASB profile. ASB refers to the profile of the sheets which is the old asbestos shape. These sheets are available in a range of thicknesses 0.8mm thick, 1.1mm thick and 1.3mm thick. Of these the 1.1mm thick is probably the most popular as it is strong enough for most domestic applications whilst still being cost effective.

Other corrugated profiles include 6” or often referred to as ‘big 6’, greca which is often referred to as box section and miniature often called mini. These sheets will cover most applications from small domestic roofs through to commercial applications such as factory / industrial roofs.
As sheets are lightweight it is important that you pay close attention to the roofing pitch (slope of the roof) as well as the batten spacings. It is also highly important to use the right quantity and type of fixings for your sheets.

Corrugated Bitumen Roofing Sheets


Bitumen roofing sheets started life as an agricultural sheet. Often used in stables and barns these sheets are perfect for an outdoor building. In recent years corrugated bitumen roofing has been used more frequently in sheds, pergolas and garage roofs.

The roofing sheets are made from a recycled baseboard. They are vacuum treated with bitumen which ensures the sheets are incredibly waterproof. So much so in fact that the manufacturers – Gutta and Onduline both attribute their sheets with a 15 year warranty against waterproofing.

Just like corrugated plastic roofing sheets it is of the utmost importance that the fitting instructions are followed to ensure your sheets provide you with the premium lifespan they are designed to give. Roofs that are below 10 degrees should be boarded to provide a backing to the sheets and stop them deflecting under load.

Above 10 degrees roofs can be battened however the batten spacing should be installed as per the manufacturers recommendations. It is also important to use a minimum of 20 fixing nails per sheet to ensure that during windy weather the sheets remain in place.

With both types of sheets, it is important to note the lapped size of sheets so that you can accurately work out the number of sheets you will need for you roofing project. As always, we are on hand to assist you with this – just get in touch by clicking the ‘HELP’ button below, sending us an email to support@varicoltd.com or give us a call on 01922 455338.