Does a white roof stay white?
The question we get most often about the white membrane is not about the heat. It's all about the color. Doesn't a white roof just get dirty and ugly after a winter? Here's what actually happens and what you can do about it yourself.
The first year
A new white roof is chalk white. It won't stay that way, and it shouldn't. During the first winter, a layer of dust, pollen and soot settles and the roof turns from chalky white to a lighter grey. It's patina, not wear, and it happens on all light roof surfaces, regardless of manufacturer.
What's interesting is how much that dimming means. The reflection decreases, but it decreases from a high number to a still high number. A patinated white roof still reflects significantly more sunlight than a black roofing felt roof does from day one.
Why dirt has a hard time sticking
Old roofing felt is rough. The stone coating gives moss and algae thousands of small places to attach themselves, and once something has grown, it retains moisture and grows further.
The membrane lays down as one smooth, seamless surface over the whole. There are no joints, no pores and no rough surface to grab onto. The rain runs off and most of what lands on the roof runs off.
Clean it once in a while
If the roof has been standing for a few years and needs to get back to the light, not much is needed:
- Rinse the surface with an ordinary garden hose in dry weather
- Use a soft brush on the places where dirt has accumulated
- Avoid high-pressure cleaners in close proximity and avoid wire brushes, both are hard on the surface
- Keep an eye on corners and edges, that's where leaves and gravel collect
An hour with a hose once a year will keep a white roof looking good for many years.
Where it gets the dirtiest
Not all roofs patina the same. If the roof is under trees, close to a dirt road or up against a dripping wall, it collects more. A detached roof on a warehouse or cottage stays bright for much longer because there is nothing above it to sprinkle.
If the roof is shaded all day, green can grow over time. It's the same place a black roof would have gotten moss, the difference is just that you can see it more clearly on white.
What doesn't change
Patina is cosmetic. The seal is the same, the elasticity is the same, and the 25-year product guarantee applies regardless of whether the roof is chalk white or light grey. The membrane is exactly the same as the black one, only the pigment has changed.
So if you choose white to get cooler down in the building, you'll still get it in five years. And if you choose it because a bright roof looks better from the window above, you just have to expect a trip to the bathroom once in a while.
See the white roof membrane or write to us, if you are in doubt about what suits your roof.
You can find the white membrane on the product page for ours liquid roof membrane, where you can also calculate consumption.
