PVC Waterproofing Membrane Application

Here after is the Method Statement for the Application of Sarnafil F 610-12 Felt PVC Waterproofing Membrane.

Existing Roof Built-up

1. Cast in-situ concrete panels

2. Vapour control layer

3. Thermal insulation board

4. Existing waterproofing system (liquid/ bitumen or PVC membrane)

5. Leveling/ Concrete screed

6. Reinforced concrete slab

Sarnafil F 610-12 Felt mechanically fastened using Sarnafast System

7. Unroll Sarnafil F 610-12 Felt, homogenous PVC waterproofing membrane, loosely lay over the cast in-situ concrete panels and mechanically fastened the overlap with Sarnafil fastening components (membrane washers and fasteners).

8. Install IF/IG-C washers (for hard surface) and fasteners BD, centered along the 30mm line traced on the membrane. Fastener spacing is to be in accordance to the project specific calculations made by Sarnafil.

9. The fastener length must penetrate the concrete deck by a minimum embedment of 32mm. The fixation pattern must always be symmetrical (i.e. every 200mm, or every 400mm, etc.)

10. Install adjacent sheets along the lap lines marked on the membrane (120mm from the sheet edge).

Hot-air Welding Procedures

11. When hot air welding of Sarnafil membrane, the overlap area must be clean and dry. For straight seam welding (overlap is 120mm), Sarnamatic automated welding machine must always be use.

12. For hand welding, use the Leister Triac hand welder, 40mm wide nozzle for straight weld and 20mm wide nozzle for corners and detail work. The three stages are:

• Spot weld the overlap.
• Pre-weld: Weld the rear overlap area so that a 35mm opening remains for the finishing weld.
• Final weld: Sarnafil PVC hand roller should be guided at a distance of 30mm parallel to the air outlet of the welding nozzle. Always roll the hand roller fully across the seam.

13. Testing of welded seams:

• Visual seam check: Shiny surface and even quality of welding beads.
• Mechanical seam check: Use a screwdriver to slide along the welded seams to check for voids and any welding defect.
• Peeling test: At the overlapped cut the membrane into 50mm width strip and firmly peel it. Tearing point should be located beyond the effective welding seam.

14. For perimeter fixation around the roof edge or near the parapet wall, Sarnafil F 610-12 Felt membrane must be secured with Sarnafil U bars and PVC welding cord against tearing and peeling off by wind uplift.

Upstands, Flashings & Roof Details

15. Followed by the upturn membrane, Sarnafil F 610-12, hot-air welded overlap 40mm with Sarnafil F 610-12 Felt, covering Sarnafil U bars and fully adhered to the parapet wall with Sarnafil approved adhesive.

16. It can be terminated with metal strip fastened through the membrane and sealed with an approved sealant at a height at least 150mm. Or alternatively, make a groove line by saw cutting on the required height and tucked in with Sarnametal sheet (PVC coated) where the upturn membrane Sarnafil F 610-12 can be welded on it.

17. For corners, vent pipes, drains and other roof details, please refer to Sarnafil installation handbook procedures.

Water Ponding Test

18. Carry out flood test 48 hours minimum after completion of the waterproofing works. Restrict water run-off from membrane area by plugging drains and creating dams or dikes. Flood restricted area to depth of about 100 mm and maintain at this depth for 48 hours. Any punctured or defective areas shall be made good by an approved method and retested.

19. The membrane shall be cleaned and inspected before proceeding with the remaining built-up protection measure.