How to Paint a Roof



A good looking roof can really raise the value of a property. Painting the roof not only makes it look beautiful again, but protects it for years to come. In this segment we’ll look at painting a galvanised iron roof to give it a new lease of life.

The standard preparation for a galvanised iron roof is to treat all rust or other damage and then pressure wash the entire roof to get rid of dust and other dirt. Use a pressure washer with a long hose from the machine to the nozzle that will give you access to all parts of the roof while the machine remains on the ground. Being in the sun, the roof will dry very quickly and you should be able to start applying the primer within one hour.

The roof paint can be applied with a roller and brush or can be sprayed onto the roof.

It’s important to apply a topcoat to the primer within 72 hours of application. The primer becomes very hard after 72 hours as it lies on the roof in the sun and the other elements, and the topcoat will not adhere to it in this condition.

Leave the primer to dry overnight and apply the first topcoat to the roof in the morning.

There are roof paints for various types of roofs.

Application can be done using a roller and brush, or the product can be sprayed to speed up the application.

A standard of two standard thickness coats of roof paint should be applied. One coat will look ok, but the second coat will adhere to the first to give your roof the required protection from the sun and other harsh African conditions.

One of the things you don’t want to do is put one thick coat onto a roof. The roof is the hottest place on the house and if you put on a very thick coat, a skin will form on the surface of the paint trapping the moisture in the paint and it won’t be able to cure. Bubbling will occur which will cause pinholes in the paint, causing it to prematurely fail.

Each coat will dry in two hours, so you can finish two coats in one day if using a spray machine or a number of people using rollers. Start at one end of the roof and by the time you reach the other end the first section will be ready to overcoat.

The job usually takes two days to complete if you’re spraying and about five days if you’re rolling and brushing for a standard house. It is physically demanding, you’ll be up and down a ladder all day, so it’s a good idea to get a couple of helpers. I would certainly recommend spraying, you should be able to hire a pressure washer and a spray machine for the weekend, but check the price of a professional, they have their own equipment and might not cost very much more than if you do the job yourself.

This is a difficult and often dangerous job, so be aware of that before tackling it on your own.

Roof painting