Method Statement For Roof Waterproofing System

Following equipment and tools will be used as required during Roof Waterproofing System.

• Wire Brushes
• Soft Brushes
• Air Compressor
• Paint Brushes
• Paint rollers
• Scissors / Cutters
• Torch with Gas Cylinders etc.
• Wheel barrow
• Spatula
• Other Hand Tools etc.

PROCEDURE FOR WATER PROOFING:

STORAGE AND HANDLING OF MATERIALS:

• Materials shall be stored in a cool and dry place and avoid putting in direct sun light.
• Materials shall be placed in a way to avoid the direct contact with ground soil.
• Materials shall not be exposed to the fire or naked flames in any circumstances.
• Material Safety Data Sheet (MSDS) shall be followed for safety and handling recommendations.
• The materials damaged during transportation, handling or storing shall not be used at site.

LIGHT WEIGHT SCREED/FOAM CONCRETE:

• The surface of the base slab shall be thoroughly clean, dry, smooth and free of matter.
• Verify that lightweight concrete screed slopes positively to drains.
• Ensure all items to be installed on the roof which require penetrations through the roof membrane are placed prior to the application of the membrane.
• Before laying the screed, cement slurry shall be brushed across the surface.
• The screed shall be finished smooth to receive further finish as specified.
• The thickness of screed shall be as determined in the approved shop drawing.
• Screed shall be finished to a hard and dense surface free from pinholes and imperfections.
• Screed surface shall be kept moist as per project specifications.
• Saw cut or hand edged trowel tooled control joints shall be provided where indicated in the shop drawing.
• After completing curing period, control joints shall be cleaned and filled with grout as per manufacturer’s recommendations.
• If any cracks occur in substrates and prior to the laying of finish materials, shall rout out, grind, level as necessary, and fill flush with grout as per manufacturer recommendations.
• All type of vehicular or foot traffic shall be prohibited on screed during setting.
• The top of screed surface shall be cleaned, dry and free from cracks.
• Screed top surface shall be carefully cleaned and all dust shall be removed before adhesive application.

SURFACE PREPARATION FOR WATERPROOFING SYSTEM:

• Surface / substrate preparation is the most important for Roof Waterproofing System before application.
• The concrete surface / substrate shall be clean and free from contamination such as dust, oil, grease, organic growth and release agents etc.
• The surface shall be free from standing water.
• All loosely adhering particles such as mortar and cement laitance shall be removed.
• The surface would be cleaned by brushing and finally soft brushing or compressed air.
• Cracks greater than 1.6mm wide shall be rout out.
• The substrate condition shall be approved by the consultant prior to start application.
• Verify that concrete cants are provided at locations where topping abuts vertical surface.

PRIME COAT:

It shall be ensured prior to application that the surface is dry, clean and smooth.

DERMACOAT – SB shall be used as a prime coat prior to the application of the Roof Water Proofing Membrane (as recommended by the manufacturer). It is a premium quality, quick drying solvent based bitumen primer which is good for masonry and concrete to improve the bonding of bituminous materials.

APPLICATION OF WATERPROOFING MEMBRANE:

• The application of waterproofing membrane shall be done under competent personnel’s supervision and as per manufacturer’s recommendations.
• Once prime coat is cured (as per manufacturer’s recommendations and depending on weather conditions) membrane torching shall be started.
• The membrane shall be de rolled one next to each other and aligned.
• After aligning the membrane shall be roll again and start torching.
• 100 mm overlap shall be provided with another roll and torching shall be repeated.
• Once the man torching is finished, all overlaps shall be sealed thoroughly.
• The end lap shall be of minimum 150mm and staggered.
• The membrane shall be protruded at least 150 cm from the screed in all directions.
• The side and the staggered end overlap shall be in the direction of the slope.
• The horizontal membrane shall be taken up the up stands to a minimum of 30 cm while the vertical skirting membrane shall be of the slated type and shall be finished either in the groove or under a flashing strip following the details as shown in the approved shop drawing.
• Waterproofing membrane shall be installed in strict compliance with the manufacturer’s instructions.
• The items such as pipes and others passing through waterproofing membrane shall be flashed to make watertight. (details shown in approved shop drawing shall be followed)
• Typical waterproofing details of foundations above the roof slab shall be followed as per approved shop drawing.
• Unauthorized entry shall be restricted to the waterproofing areas.
• On completion of Waterproofing Membrane and before undertaking any further activity, it shall be tested by plugging the outlets and flooding 50mm above the highest point by hose and leaving flooded for twenty four hours before draining off.
• Any leaks resulting from the test shall be located and repaired (if any).
• The test shall be repeated until the roof is completely watertight if found any leakage or damage.
• Prior to concealing the waterproofing membrane, IR shall be raised for approval. All subsequent works shall be carried out only after getting written approval.
• On completion of successful flood test and draining out the water, the next components of the system like insulation boards, separation layers can be laid.
• The termination detail of membrane and fixing of aluminum flashing / application of required sealant to the skirting flashing shall be completed following the approved shop drawing.
• White cement tiles (400x400x40mm) and 10-20mm screen washed gravel shall be laid as per design / pattern shown in the approved shop drawing.