Flat Roof Replacement - A Look at Your Options

Flat roofs are a common feature of many homes in Europe and the United States, they're cheaper to construct and easier to replace than a tiled roof. That's why specifiers include them in the designs of so many homes.

Unfortunately, a flat roof is far more likely to hold water and leak that a sloped and tiled roof.

Traditionally these roofs were covered with tar and felt to keep the water out and had a life expectancy of around 15 years. Recent innovations have led to the production of materials that will last over 50 years if installed to the manufacturer's instructions.

But which material is best for your roof? What is the best option for the price?

This page is an introductory guide to the pros and cons of the most popular flat roof coverings on the market today.

If you want to discover how much each of these materials cost to install, head over to Quotations guide to flat roof Torched Felt

These felts have a bitumen backing which is heated up with a gas torch, the bitumen binds layers of felt together to create a waterproof seal.

Pros - one of the cheaper options and can be overlaid with stone chippings for a neat finish. There also plenty of tradespeople that can lay these felts as the skill level required isn't high.

Cons - requires the use of a naked flame during installation. Also, you shouldn't walk on this felt during very cold or very warm weather as the material is brittle in the winter and very soft in the warm summer.

Rubber Roof Membranes

Sheets of specialist thick rubber can be glued to the timber decking on most flat roofs. These products last up to 50 years and can be installed by DIYers as there's no naked flame or heat source needed.

Pros - prices have come down in recent years and there's plenty of choices. They can be fitted by any competent person and last for years.

Cons - they don't look great and sometimes crease. Also, because they're so easy to install, they're the preferred material for tradespeople who have little knowledge of flat roofs.

Mastic Asphalt

This material was once the ideal option for flat roof coverings but fewer and fewer tradespeople now offer this service. It's very hard to lay correctly and the work must be done by an expert, ideally with many years experience.

Pros - the most aesthetically pleasing option. Very tough and can be walked on all year-round.

Cons - it's difficult to find specialists as this is a dying trade. Mastic Asphalt is costly and isn't always compatible with other materials on the roof. It's also very heavy and some roof structures with thin timber work may bend or buckle under the added stress.


Fibreglass is normally used on boats as it's waterproof, strong and lightweight. These properties make it a very good material for using on a flat roof instead of heavy mastic asphalt.

Pros - reasonable prices and looks appealing, it's also very lightweight which is a trait that's beneficial in some situations.

Cons - is very slippery when wet or covered in algae, large areas also suffer from cracks and splits and this material is better suited to a smaller roof that doesn't flex. This material cannot be applied in damp or wet conditions and is difficult to apply on windy days. Fibreglass should only be applied to new and sound timber decking, this could add considerable cost to the project as decking sheets are very expensive.

The Best Flat Roof

There is no right or wrong material to use on a flat roof, each option has its own pros and cons.

Rubber felts are very popular and have overtaken bitumen systems as the number one choice by roofing contractors in the UK.

Article kindly provided by quotationcheck.com

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