How Often Should You Coat a Flat Roof?

Flat roofs are a great choice for a number of reasons; they are affordable, easy to install and very energy efficient. However, to keep your flat roof in good condition, it needs to be maintained properly. A key part of flat roof maintenance is ensuring the waterproof coating remains intact, but how often should you coat a flat roof?

Why do flat roofs need recoating?

The main reason for recoating a flat roof is to protect it against water. If ponding does occur due to heavy rain, the roof can leak and cause damage inside the property.

Flat roofs should be properly coated and weatherproofed when they are installed, but over the years, the weather takes a serious toll on the health of the roof. Sun, frost, ice, strong wind and heavy rain all start to deteriorate the coating.

Recoating refreshes the weatherproofing properties of your flat roof, protecting it from UV rays, leaks and more, while also preventing heat from escaping, thereby reducing energy costs. 

How often should you coat a flat roof?

Without any maintenance or recoating, a flat roof will typically only last about 10 years. To make your roof last longer and reduce the chance of leaks and damage to the interior of the house, it is a good idea to reseal the roof with a new coating every five years. 

However, several factors can affect this and may mean your flat roof needs recoating more often than every five years. The following factors may affect this timescale.

Regular inclement weather such as intense heat, sun, rain, or wind

While the occasional instance of bad weather is to be expected, and shouldn’t challenge your roof, you should have it inspected after any prolonged periods of extreme weather.

If the roof has had a leak

A leak means the flat roof coating has failed and, once the source of the leak has been identified and fixed, the roof will need recoating. Similarly, if you notice ponding or structural damage such as rot inside the roof, then this could be an indication the roof needs a new coat.

If the roof has been damaged by debris

When the roofing material is damaged, it can no longer effectively do its job of keeping the weather out and the heat in. If you notice any damage or holes in your flat roof material, these should be patch-repaired first, and then the whole roof should be recoated. 

How to recoat a flat roof

The first thing to keep in mind if you are planning on recoating your flat roof is to carry out the work on a day that is forecast to be dry and ideally a moderate temperature.

The rooftop also needs to be clean and free of debris, and any seams that need repairing should be fixed before applying any coating material.

A primer should be applied to the roofing surface before the coating material is applied. Roof coating material is available in either water-based or solvent-based forms. Solvent-based coatings tend to be more expensive and require an expert application, but also last longer and can withstand harsher weather conditions.

Whichever roof coating material you buy should be applied by following the manufacturer’s instructions.

To summarise, you should recoat your flat roof every five years, providing it is otherwise well-maintained. However, if you experience prolonged periods of inclement weather, or your roof becomes damaged in any way, you may need to recoat it sooner.If you are unsure about the current state of your flat roof or need any advice, you are welcome to get in touch with our expert roofers.