Quick answer
Roof heat proofing reduces the sun's heat that a flat concrete roof soaks up and passes into the rooms below. The simplest step is a light-coloured coating on the roof: a light surface reflects more sunlight than bare grey concrete, so the slab heats up less. Because a roof that leaks also loses any heat-proofing layer, do it together with waterproofing: repair cracks, then apply a light-coloured elastic membrane such as Sikalastic-510 over the whole roof. For a large drop in indoor temperature, an insulation layer (for example foam boards under tiles) is added as well; check each product's datasheet for its colour and reflectivity before choosing.
Common causes
- Bare grey concrete or dark roof surfaces absorb most of the sun's heat
- A thin roof slab with no insulation layer passes the heat straight into the room
- Cracks and leaks that let water in and ruin any insulation or screed
- Old mud and brick-tile layers that crack and hold water instead of insulating
Step-by-step
- 1
Check and clean the roof
Sweep the roof, remove loose material and old flaking coatings, and clear the drains. The surface must be sound, clean and dry.
- 2
Repair cracks and joints
Fill cracks and seal the joints at parapet walls, pipes and water tanks first, so the coating lies on a watertight base.
- 3
Prime
Apply the primer coat recommended on the coating's datasheet and let it dry.
- 4
Apply a light-coloured coating
Apply 2–3 coats of a light-coloured elastic roof membrane such as Sikalastic-510 at the rate on its datasheet, each coat crosswise to the last, reinforcing cracks and corners with Sika Fab-1 mesh.
- 5
Add insulation if needed
Where the room below still runs very hot, an insulation layer under protective tiles gives a further drop; ask us which build-up suits your roof.
- 6
Keep it clean
Dust and dirt darken a light roof over time. Wash it occasionally, and re-coat as the datasheet advises.
Always follow the current Sika Pakistan product datasheet for surface preparation, temperatures and curing.
Products for this job
Sikalastic-510 PKElastic acrylic roof membrane: waterproofs and gives the roof a lighter surface.From Rs. 19,580
Sika MultiSeal BTSelf-adhesive tape to seal joints and flashing before coating.From Rs. 1,799
Sikaflex ConstructionPolyurethane sealant for roof movement joints.From Rs. 4,000
Sikadur-20 Crack SealEpoxy that runs into fine cracks before the coating goes on.From Rs. 3,995
Frequently asked questions
What is roof heat proofing?
It is any treatment that cuts how much of the sun's heat a roof absorbs and passes into the rooms below: a light-coloured reflective coating, an insulation layer, or both. In Pakistan it is usually done together with roof waterproofing.
Does a white roof coating make the room cooler?
A light-coloured roof surface reflects more sunlight than grey concrete, so the slab heats up less and the room below is usually cooler. How much cooler depends on the roof, the coating's reflectivity and whether there is insulation, so no exact figure can be promised.
Can I waterproof and heat proof the roof at the same time?
Yes. Repair the cracks, then apply a light-coloured elastic waterproof membrane such as Sikalastic-510. One system blocks the water and gives the roof a lighter surface.
Chhat ki garmi kam karne ka tareeqa kya hai?
Chhat saaf karein, cracks bharein, phir halke (light) rang ki waterproof coating lagayein jaise Sikalastic-510. Zyada garmi ho to coating ke sath insulation layer bhi lagwayein.
How much does roof heat proofing cost in Pakistan?
It depends on the roof area and the system. Use the coverage rate on the coating's product page to work out the number of packs; live prices are on every product page.