Best Roofing Materials for a Flat Roof

Whether you are planning to replace an existing flat roof or cover a new one, you will want to use the best products for the job.

Flat roofs are often used for a number of different buildings for example;

  • House extensions
  • Garages
  • Industrial buildings

They are seen as a cheaper option than a pitched roof.

Choosing the Material

When you choose the product to use you will need to consider things like:

  • The strength of the existing roof joists
  • How much weight they can hold
  • The life expectancy of the product
  • The environment that it will be used in
  • Any potential guarantee from the manufacturer or installer.

There are many types of material that you can use for a flat roof, including roofing felt and fibreglass.


A popular and traditionally used roofing product is roofing felt, this comes in several layers which are heated up with a blow torch as they are installed. The layers are; a vapour layer to aid ventilation and prevent damp, a reinforced felt layer and finally a top cap layer. The sheets are cumbersome to handle and will need a professional roofer to do the installation.

A good feature of roofing felt is that it can be patched up if repairs are needed, and it is one of the more economical roofing choices. The more modern types of roofing felt are far more reliable and long lasting than the older types.

Liquid Tar and Gravel

Another common type of roofing that's been around for years is a built-up type where liquid tar is poured onto your roof and gravel is used to top it. This needs to be done in several layers, which can weigh heavily so you will need to ensure the roofing is strong enough beforehand.

As several layers are needed it can be slow to install and is likely to be a strong-smelling, messy job. This will produce a really waterproofed roof which will be hard wearing. If the flat roof is in use as a terrace or you can see the flat roof, it may be possible to choose your colour of gravel so as to blend in with the surrounding building.

This can be a more costly way of covering your flat roof due to the amount of work involved but once it is fitted it will be low maintenance and can last as long as sixty years if a modern polymer type is used.


Rubber is also a popular choice of material as it is extremely water resistant even to salt water, so would be ideal for use on coastal properties. The rubber material is so waterproof you can even use it to line a pond.

Rubber roofing is ideal for smaller roofs as you may even be able to install it as one large sheet, similar to lino on a floor. This style of roofing is not ideal for complicated roofs with gutters or lots of pipes as you will end up with too many joins which could leak.

By laying it as one sheet you will have no problem with joins in the material and the need to waterproof them.

Rubber is an environmentally friendly choice as it is made of recycled rubber. The material is also good at keeping the heat in the building below during cold weather, saving money on energy costs and it helps keep out excessive summer heat, keeping the building cooler. This type should last between thirty to fifty years and it is relatively easy to repair if needed.

It is possible to paint rubber roofing, so you can customise it to fit your surroundings. It is also very UV resistant and will not crack and split as it ages. At the end of its useful lifespan as a roof, this rubber roofing can be recycled again into other useful things.

Liquid Roofing

A newer type of material is liquid roofing, this is very flexible when you have a roof that is an awkward shape or layout. The liquid material is spread out over the roof deck, where it forms a coating with no seams to worry about.

This liquid mixture is more expensive to purchase but its simple installation can be fairly speedy, helping keep costs down. The great thing about liquid roofing is that it lets moisture escape from the house below, whilst still being extremely waterproof from the outside. It is a flexible product that can allow for the natural movements of the building. It is a strong product that should last more than twenty-five years.


Another popular material choice is fibreglass, this is a more expensive choice, but is strong and lightweight. Fibreglass roofing is good for smaller roofs, due to the fact it can expand and contract in different weather conditions. This sort of roofing does need to be fitted by an experienced roof installer.


Metal can be used as a flat roofing material, it is usually aluminium that is used these days. Metal is useful as it does reflect some heat away from the building and it is naturally fireproof. You will need to consider adding suitable soundproofing under a metal roof otherwise rain on the roof is deafening.