Quick answers
Is it worth making my roof white? Does it really keep the home cooler?
A white waterproof coating reflects much of the sun, so the roof and the floor below heat up less. It doesn't replace insulation, and it needs renewing once it gets dirty and worn.
A dark roof soaks up the sun and gets scorching at midday in summer. A white surface reflects it, so the slab heats up less and less heat passes into the floor below. That is the idea behind a cool roof coating.
On this roof the old dark coating had worn out: shiny in some places, frayed in others, with a hole at the base of a railing. The damage was repaired first, and the corners, railing bases and joints were covered. Then the white waterproof coating was spread over the whole surface and up the parapets.
The white here isn't ordinary paint. What goes on is a flexible waterproofing product whose first job is to keep water out; the colour is a bonus. Nor does it replace insulation: when a roof has insulation underneath, such as polyurethane foam, the white layer on top also protects that from the sun.
Over the years a white surface collects dust and wears, especially where water sits, and it reflects less. On a roof with vent pipes, the old white coating had turned grey and worn through in many places. It was washed and given two fresh coats of white waterproofing, with care around the pipes and along the parapets.
Jobs that show it
A Dark Roof Terrace Turned White
A roof with an old, dark coating and worn edges was repaired and covered with a white waterproof coating that reflects the sun.
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Renewing the White Waterproofing on a Roof with Vent Pipes
A roof's old white coating had gone dirty and worn. It was washed and covered with a fresh white waterproofing, with extra care around the vent pipes and along the low walls.
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Terrace with Iron Railings Waterproofed in White
The terrace's old, stained coating was cleaned and primed, then the floor and low walls were covered with a white waterproof coating.
See the job step by step