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Underground TankingLift Pits

Lift Pits


The blinding layer shall be surface dry, clean and smooth; free of voids, protrusions and contaminants. The area is then to be primed using a bituminous primer. Internal corners shall be filleted and external corners rounded. Concrete walls are to be smooth off-shutter (board-joints rubbed smooth and ferrule holes filled) and to be free of voids and honeycombing. Care is to be taken to remove shutter release oils and all remnants of curing compounds. The concrete is to be cured and dry - generally accepted as when the bituminous prime coat achieves full adhesion. Brickwork is to be dry and smooth either bagged or plastered so as to achieve a uniform finish free of voids and protrusions. Concrete footings and bases are to be clean, dry and smooth. Internal corners to be coved.


Horizontal       One layer Derbigum CG4 on one layer Derbigum CG3, laid staggered, with side laps of 75mm and end laps of 100mm, sealed to primed blinding layer by “torch-fusion”, followed by one layer of standard pressed wood, laid loose on waterproofing as protection layer.

Vertical           One layer of Derbigum CG4 on one layer Derbigum CG3 waterproofing membrane, with 100mm side laps and 150mm end laps, sealed to primed surface by “torch-fusion”, to receive protection or drainage layer and compacted fill (elsewhere specified by engineer). Waterproofing to be installed by an Approved Derbigum Contractor.

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