AFM Roofing System
Installation of the system
Remove existing decking and roof covering then de-nail the joists to provide a clean surface to the joists. If the roof is insulated it is important that cross flow ventilation is provided for by cross battening the roof. If required timber firing pieces should be fixed to the roof to create or improve the fall on the roof, the minimum fall is 1:80
Mechanically fix new spruce plywood deck 111/111 min. grade. Recommended fixing method is minimum 24 fixings per 8x4 sheet using 75mm ring shank nails or screws. Boards should be Staggered with long edges 90 degrees to joists, with 3mm expansion gaps between board joints and 20mm at wall abutments. End joints to be centred on joists, ensure fixings do not protrude above the surface of the board. OSB such as smart ply is not recommended.
Mechanically fix AFM trims to the perimeter via 20mm galv. Clout nails @ 150mm spacing 50mm from the edge of the trim. Water run off and water retention trim to be reinforced at the joints with butt straps.
Using 75mm wide fibreglass tape, wet out (apply afm basecoat to the tape) and cover joints with 2 layers ensuring the edge of the tapes are feathered out to reduce the visual impact. At each joint on the plywood deck lay 75mm wide tape and apply base coat resin. Consolidate using the paddle roller ensuring the edges are softened
Laying the AFM roof system
Pre-cut the fibreglass matting to the appropriate length and roll up lay aside for future use. Catalyse the base coat resin at the appropriate % dependant upon temperature min 2% max 4%. Using the medium pile roller on an extension pole lay of coat of resin onto the deck the width of the matting (1 metre) . Lay the matting onto the resin and unroll, apply another coat of resin on to the fibreglass, consolidate using the paddle roller on an extension pole pay particular attention to the edges of the matting ensuring full saturation of the fibreglass. The rate of application is 1.5kg. Per m2. Repeat this process across the roof overlapping each roll of matting 50mm onto the previous one. Allow the basecoat to cure approx. 30-60mins depending on temperature. when cured sand down any fibres which are proud. Then apply AFM topcoat to the whole area.