No roof coating product can be expected to repair an existing roof which is not structurally sound and stable. Before using a surface coating the roof structure should be inspected and, if necessary put in order. All cracked, broken, slipped or missing slates, tiles, sheets or other forms of covering should be replaced or re-fixed, and cracks in felt or asphalt filled.
Care needs to be taken over preparation of surfaces before application and this will influence the degree of adhesion and life of the renovation. All surfaces must be free from oil, dirt, dust and loose debris. All traces of algae and fungus growth should be removed using a stiff brush and the surface treated with a fungicide to kill any remaining spores thereby discouraging the return of any growths.
Asphalt Roofs:
On asphalt roofs where blisters have occurred, these should be heated with a blow lamp until soft and then smoothed out. If the asphalt is crumbling or badly cracked, it must be removed and replaced with a polyester based underlay.
All Weather Roof Coat should be applied by brush in two coats, the first being allowed to dry before the second is applied.
Built-up Felt Roofs:
Remove any loose chippings and carry out the preparatory work detailed above. Minor marks and defects will be effectively filled and covered by All Weather Roof Coat but where these are wider than 0.75 mm they should first be filled with Trowel Mastic and allowed to dry.
Blisters in roofing felt should be opened out, cleaned with a stiff bristled brush and coated with All Weather Roof Coat at 1.5 m2 per litre.
The All Weather Roof Coat should be allowed to set until it becomes tacky and then the felt should be re-fixed by bonding it down.
In each of the above cases the All Weather Roof Coat and a glass membrane should then be applied.
Asbestos-Cement Sheeting:
Carry out preparatory work. It is particularly important that the asbestos cement is not saturated with water before protective coating commences. Wait until the asbestos cement sheeting is dry and then apply one coat of Cromar Bitumen Primer. Allow the primer to dry and apply two coats of All Weather Roof Coat. Ensure that complete contact is achieved and no air is trapped beneath the All Weather Roof Coat.
Metal Surfaces:
Where these show signs of corrosion, such as loose rust, this should be removed by using a wire bristle brush. A rust inhibitive treatment should be applied to ensure that the rust will not return. For normal circumstances, scrubbing with a wire brush is sufficient preparation. All Weather Roof Coat should then be applied in two coats at the rate of 1.5 m2 per litre per coat.
Slates and Tiles:
Carry out preparatory work. The roof should be examined for damaged or loose slates or tiles. Any loose tiles or slates should be re-fixed firmly in place. All Weather Roof Coat and a glass membrane should then be applied.
Scrim Treatment:
In order to bridge gaps, cracks and fissures and in all cases where roof surfaces are in an advanced state of decay, it is recommended that All Weather Roof Coat be used in conjunction with a reinforcing membrane, either rot-proof hessian or, preferably, glassfibre membrane.
Having ensured that the surface is clean and receptive to the coating product, apply a first coat at 1 m2 per litre.
Immediately apply the glassfibre membrane into the wet All Weather Roof Coat film using a brush charged with All Weather. Ensure that complete contact is achieved and that no air is trapped beneath the All Weather Roof Coat.
The glassfibre membrane should be lapped by 50 to 75 mm and the inside of each lap should be painted with the All Weather Roof Coat. Small gaps and differences in levels should be bridged ensuring that the glassfibre membrane is not pulled too tightly across the gap so that any movements in the structure will be accommodated.
At walls and parapets, continue the glassfibre membrane and All Weather Roof Coat sandwich vertically for at
least 150 mm and secure using self adhesive flashing (150 mm width) allowing 75 mm to be in contact with the
brickwork above. Apply a second coat of All Weather Roof Coat and allow this to dry.
Final Surface:
It is beneficial to the coating, and to the rest of the roof structure, to give a final solar reflective finish. An exposed black bituminous surface should be avoided on a pitched or flat roof. When using All Weather a third and final coat should be preferably applied at 1.5 m2 per litre. While the film is still tacky, bond with 1 to 2 mm (7 to 14 mesh) stone chippings or clean sharp sand. Alternatively the final All Weather coating should be allowed to weather for a minimum of two weeks (preferably one month) then a solar reflective coating can be provided using Cromar® Aluminium Paint.
Vapour Barrier:
When insulating material is placed on a flat roof deck it is essential to prevent condensation water vapour from entering the insulation. If this is allowed to happen it can damage the insulation. Two coats of All Weather, the first applied at 1 m2 per litre, the second at 1.5 m2 per litre, will help prevent this. The All Weather should be applied to the ‘warm’ side, with care being taken to avoid pin holes and imperfections in the coating. After the All Weather has dried the insulation may be applied over it.
