Cold Roof vs Warm Roof

Is there the telltale sign of damp creeping across your ceiling?

But, what exactly is the difference, and why should you bother getting a warm roof to combat damp?

Well, first of all, damp can be very detrimental to your health. It can give you respiratory issues, or make existing ones worse. It can even affect your immune system, which is bad news for everyone. It also doesn’t look very nice when there’s lots of black spots all around the house. 

Below is a case study of a recent customer who had no end of problems until we changed the roof over from a cold roof system to a warm roof.

The home was covered in spots of mould and damp. They had a flat, cold roof. 


We converted the flat, cold roof into a warm roof adding a slight inversion to prevent water from pooling (another factor to the mould). 

Next up, a little lesson on roof construction.

A cold roof is probably what you currently have in your home – conventionally, it’s how they’ve been built, or the way they have been retrospectively insulated if your home is older than the concept of loft insulation. The roof covering – felt or tiles – is at the top, way up there with the rafters and the batons. Then there’s the open space – space that is generally the same temperature as it is outdoors. Just above your ceiling there are joists, and here’s where that stuff that looks like a blanket gets laid (only, it tends to be itchy, so we don’t recommend using it as an actual blanket). A flat roof is similar, except there’s slightly less open space – not enough to convert.

A warm roof also has the same joists above your ceiling, and the same covering right up on the top. The difference is where the insulation is – it’s up there in the rafters just below your tiles or felt. The space in your roof is within that insulated barrier – meaning the temperature reflects the temperature of your house, rather than what’s outside. A warm roof has the same protection against damp as the rest of your house, as your heating keeps the moisture at bay.

For advice on if a warm roof would be right for you, please do get in touch to speak to one of our team. 

And, if you’d like a new roof; whether you need warm or cold, whether you’ve got a pitch you want making flat, or a flat roof you’d like adapting to a pitched, #ChoosePrimus. 

Next week, I’ll be giving you a little intro in Velux roof windows (skylights) and sun tunnels, the gorgeous trend that gives you plenty of natural light.