The surface is thoroughly cleaned and should be free from dust, dirt loose materials, oil or grease.Cement-Sand (1:3) mix would be placed along corners of walls or neck columns and any other junctions.

For horizontal waterproofing membrane application. Two layers of 4mm thick modified bituminous membrane shall be laid fully torched on blinding concrete with a minimum of 100m side laps and 150mm end laps.The blinding surface shall be primed with the bituminous primer.

Waterproofing membrane installation shall be performed using cylinder fed propane gas torch, trowel to seal the seams of the membrane and knife for cutting. The membrane is then placed in the correct torching on position then re-rolled for about half of its length without changing its orientation. The membrane is then un-rolled again and torched on pressing the melted area against the substrate.Repeat till the entire length of the membrane is bonded firmly onto the surface then the second membrane is laid in the same way with an overlap of 150mm at the end and 100mm at the side.

An extra length of minimum 300mm of the horizontal membrane shall be left to carry up the vertical surface to maintain continuity of the membrane and be protected as above.

For Vertical Application, two layers of 3-4mm thick modified bituminous waterproofing membrane shall be applied to all vertical surfaces of gunited shoring or block works wall.The extra portion of 300 mm of the horizontal membrane left shall be turned up and wrapped on to the vertical primed surfaces. The continuity of the membrane shall be maintained by minimum laps of 150mm.The membrane on the exposed external vertical surfaces shall be carried up to a minimum of 150 mm above the finished ground level (i.e. sidewalk, parapet, etc.)