Surface preparation
Before installation of new roof covering ensure that:

Surfaces to be covered are firmly fixed, clean, dry, smooth, and free from frost, contaminants, voids and protrusions.

All preliminary work including formation of upstands, kerbs, box gutters, sumps, grooves, chases, expansion joints, etc. and fixing of battens, fillets, anchoring plugs/strips, etc. is complete and satisfactory.

Existing roof constructions must be checked to ensure that any insulation elements are dry and free from moisture.

Vapour Control Layer
Approved Polythene vapour control layer, loose laid and lapped in accordance with Moy Materials recommendations, detailed to envelope insulation board at perimeters and penetrations.

Insulation
Paratherm Foil, P.I.R. (CFC, HCFC and HFC free, Zero OPD, GWP 3) foil faced thermal insulation, to selected thickness. Mechanically fix with approved fixings and plates in accordance with manufacturer’s instructions, incorporating 50mm timber angle fillets at upstands and kerbs. Fixing rate as per manufacturer’s recommendations.

Membrane
Vinitex MP 1.2mm thick, BBA certified, PVC single ply membrane, mechanically fixed in strict accordance with manufacturer’s recommendations. Wind load calculation form to be completed prior to calculation of fixing centers. Form welded lap joints with approved equipment. Membrane side lap welds to be a minimum of 40mm and membrane end lap welds to be a minimum 25mm. Seal all side and end laps by hot air welding. Clean and dry the joint surfaces for the full width of the lap prior to welding. Test the joint after welding by drawing a seam probe along the seam edge. Make good any defective welds. Carry out a peel test every 200 linear meters.

Detailing

  • All upstands to be minimum 150mm above finished roof level. Form with Vinitex MP, 1.5mm membrane, hot air welding onto clad metal / termination bar.
  • Edge trims and drips to be formed from Vinitex clad metal, screw-fixed using approved fixings in accordance with manufacturer’s recommendations.
  • Form corners with Vinitex SA, 1.2mm membrane, or with prefabricated Vinitex internal/external corners.
  • Weather all soil vent pipes and other roof penetrations with Vinitex SA 1.2mm membrane, glued to the penetration using Vinitex contact adhesive, hot air welded to the field area and secured using a jubilee clip to ensure a complete seal.
  • Fit Moy Retrodrain roof outlets with leaf grates compatible with Vinitex PVC membrane. Dress Vinitex MP 1.5mm membrane into new outlets, ensuring leaf grates are installed upon completion. Recess onto the roof and firmly secure with no lip preventing the free flow of water.
  • Seal all end laps with 100mm wide Vinitex MP cover strips.
  • Secure Vinitex membrane with peel stops and Vinitex MP cover strips around perimeters, changes of plane, curb flashings, upstands to rooflights and penetrations with approved mechanical fasteners in strict accordance with manufacturer’s recommendations, sealing over with Vinitex MP cover strips.
  • Terminate Vinitex membrane in horizontal plane immediately adjacent to any change in direction, secured with peel stops and Vinitex MP cover strips.
  • Dress all Vinitex MP cover strips over peel stops by a minimum of 50mm.

Completion
Ensure that all roof areas are left clean with all outlets clear. All work by others necessary to provide a weathertight finish is satisfactorily completed. Defects are repaired without delay to minimise damage and nuisance.

Issue Moy Materials warranty upon satisfactory final inspection by Moy Materials technical staff.