How to apply the Overcoat roofing system to waterproof Asbestos roofing
Surface preparation
Any dirt, soil or other contaminants must be removed from the roof's surface before installing the Overcoat Liquid Roofing System. After the initial cleaning, the surface should be power washed and rinsed to remove all residual dirt and contaminants after which the surface should be dried.
Fill any splits in the Asbestos will Sharkseal multi-surface sealant, applying the product to all seams and around all fixings. Any cracked sheets, open laps or fixing holes should first be bridged with a bead of Sharkseal, keeping the asbestos substrate sound and watertight ahead of the first coat.
Applying the primer
This surface requires the use of the Overcoat high-performance porosity primer. Once the surface is dry apply the primer at a coverage rate of 100gms per square metreOnce the primer has been applied, allow 5 hours for the layer to cure before applying the Overcoat system.
In damp conditions, a moister tolerant primer needs to be applied which is a two-part mix. This is applied to the surface at 125gm per square metre and will need a minimum of 5 hours to fully cure.
Applying the Overcoat
Once the primer has cured you apply the Overcoat system with a standard roller or brush at a rate of approximately 1.2 kg per square metre. The Overcoat layer will become instantly watertight and can immediately withstand rainfall. After 24 hours the surface can take foot traffic and a full cure of the system will take around 7 days.