Part- 3 (Specifications)
Section - 9
Roofing & Waterproofing, etc.
Section - 9
ROOFING & WATERPROOFING
AND PROTECTION TO SUBSTRUCTURE
9.1 SCOPE :
These specifications cover flat roofs of reinforced concrete construction including thermal insulation, waterproofing and surface finishing.
9.2 QUALIFICATION :
The waterproofing systems including protection and all associated accessories and works shall be executed by a specialist firm(s) to be approved by the Engineer
The manufacturer's qualified representative shall visit the job site immediately prior to commencement of works and as and when required and directed by the Engineer to satisfy the Engineer and to instruct the specialist(s) in the correct methods of execution of the Works.
9.3 TESTING :
The waterproofing system upon completion shall be subjected to testing by flooding with water up to a depth of 100mm above the highest point of the screed laid to slope but limiting the depth to ensure that the average weight of the water so flooded does not exceed 150 kg/m². The water shall be retained for a period of 24 hours. The Contractor shall arrange for all, water, other materials and labour required for the execution of the test, inspection of works and for any making good of works or any associated works that may be required at no extra cost or time to the project.
9.4 GUARANTEE :
The Contractor shall submit to the Engineer a guarantee stating that all Works have been carried out in accordance with the drawings and specifications and shall be guaranteed free from defects in material and workmanship and shall be leak-proof for a period of twenty-five ( 25 ) years from the date of issuance of the completion certificate. The Contractor shall agree to repair (including any replacement of materials) any leaks resulting from defective materials or workmanship during the guarantee period at no additional cost to the Client.
The Contractor shall also pass on to the owner any and all guarantees provided by the sub-contractor and manufacturers of individual members of the system.
9.5 ROOFING
The roofing and terraces or open to sky areas shall comprise the following layers :
9.5.1 Combo Roofing System
Proposed ‘Combo-Roof’ waterproofing system shall include following materials & works to be supplied and installed by an approved manufacturer with lifetime guarantee of twenty-five ( 25 ) years :
a) Roof slab shall be inspected by a roofing specialist from the manufacturer’s office and confirm acceptance of the roof for application of the ‘Combo-Roof’ waterproofing system.
b) Clean the roof using compressed air to make sure substrate is free of dust and debris.
c) Supply and spray apply ‘Polyfoam’ or equivalent approved to the specified thickness (to meet thermal insulation standards) over the entire roof area including the upstand to a height of maximum 200mm.
d) Supply and spray apply ‘Polytex’ or equivalent approved over the entire foam area and allow to dry for 48 hours.
e) Flood test the roof for a minimum period of 24 hours.
f) Supply and lay ‘Polyfab’ or equivalent approved protection layer over the entire roof area.
g) Supply and fix ‘Polyboard’ or equivalent approved expansion joint filler boards in slope and in panels.
h) Supply and lay protective screed in panels and cure as per standard procedures.
j) Supply and apply ‘Polyflex’ or equivalent approved over the entire roof area including upstands, and allow drying for 48 hours.
k) Final inspection shall be carried out and the manufacturer shall issue a lifetime guarantee of twenty-five ( 25 ) years.
Procedure and Scope of Work :
1.0 Upon casting and complete curing of roof slab, Manufacturer’s Engineer shall visit the site to inspect the roof and accept the roof for waterproofing & heat insulation works. A preliminary site inspection shall be carried out and any further preparation work if required shall be brought to the attention of the Main Contractor. Prior to commencement of roof waterproofing works, Main Contractor shall make sure following conditions are met :
1.1 All joints existing between roof slabs other than expansion joints provided shall be filled with mortar.
9.5 ROOFING [Cont’d]
9.5.1 Combo Roofing System [Cont’d]
Procedure and Scope of Work [Cont’d]
1.0 1.2 All electrical conduits and other service entries to slab shall be closed with mortar.
1.3 Sides of electrical conduits and service entries shall be sealed with mortar.
1.4 Rainwater pipes shall be in place at specified height as per slope.
1.5 Vertical parapet wall shall be plastered to the required height.
1.6 Roof door threshold shall be in place.
1.7 AC or water pipe sleeves shall be in place at a minimum height of 200mm.
1.8 All other works on the roof shall be completed prior to commencement of waterproofing works.
2.0 On acceptance of roof from the Main Contractor, application crew of the approved manufacturer shall visit the site to commence mechanized cleaning operations using compressed air to free the entire substrate from dust and any other loosely lying particles.
3.0 On completion of cleaning works, other preparatory works shall be undertaken like covering of parapet wall and other utilities fixed on the roof to avoid the risk of over spray.
4.0 Upon completion of preparatory works ‘Combo-Roof’ system application shall commence where a combination of Polyol & Isocynate is sprayed onto the roof slab including upstands using Gusmer’s (USA) combination equipment. The spray applied system forms an impermeable waterproofing cum insulation layer with high thermal resistance, closing all pores and cracks that exists in the roof slab.
5.0 On completion of polyurethane foam application, ‘Polytex’ acrylic liquid waterproof coating shall be applied over entire foam using airless spray equipment to form a uniform coating of maximum thickness 800 microns.
6.0 Once acrylic coating is completely cured for 48 hours, Manufacturer’s Engineer shall visit the site to inspect the works completed and carry out a flood test for 24 hours. On successful completion of flood test, a test report shall be prepared and maintained for records.
7.0 Upon successful completion of flood test, water shall be removed and ‘Polyfab’ geo-textile membrane shall be laid as a protection layer over the entire roof area prior to commencement of screeding works.
9.5 ROOFING [Cont’d]
9.5.1 Combo Roofing System [Cont’d]
Procedure and Scope of Work [Cont’d]
8.0 Manufacturer’s Engineer shall make level markings for screeding at site and screeding crew of the manufacturer shall commence the paneling work using ‘Bolyboard’ expansion joint filler board and pre-mixed cementitious adhesive mortar to attain the desired slope levels as indicated in the approved drawing.
9.0 Protective screed shall be laid in panels and angle fillets done of size 50 x 50mm and cured as per standard procedures.
10.0 Once screed is completely cured, ‘Polyflex’ acrylic cementitious water-proof coating shall be brush applied over screed including upstands to form a uniform coating of maximum thickness 1000 microns.
11.0 Once the final coat is completely cured for 48 hours, Manufacturer’s Engineer shall visit the site for final inspection and a lifetime guarantee of twenty-five ( 25 ) years shall be issued.
9.5.2 Balconies and Wet Area Waterproofing
For wet areas such as baths, toilets, kitchen and balconies, minimum 5cm thick smoothly finished screed to slopes to be provided. Apply two ( 2 ) coats of polyurethane liquid applied membrane such as ‘Duseal R-300’ or approved equal, forming a minimum 2mm thick uniform layer of waterproofing. Waterproofing on angle fillet and on walls up to 8" high above finish floor level shall be done and areas around the bathtubs, vertically up to height of bathtub plus 8" extra waterproofing shall be applied. Minimum five ( 5 ) days to be allowed for curing prior to opening for services. Minimum ten ( 10 ) years guarantee required for wet areas waterproofing as well.
9.6 PROTECTION OF SUBSTRUCTURE :
All reinforced concrete substructures including base slab, retaining walls of basement, etc. shall be protected from aggressive action of soil, ground water and all detrimental influences due to soil quality at the Site by provided torch welded 5mm thick SBS membrane with 250 kg/M² tough non-woven polyester reinforcement as explained below :
9.6.1 Horizontal Surfaces :
Double layer of 5mm thick SBS modified bituminous membrane such as ‘Dulas-250-QP’ from “Duproof” or approved equal shall be laid fully torched on to the blinding concrete with minimum of 150mm laps all around. Before applying the membrane, the blinding surface shall be suitably primed with a primer recommended by the manufacturer of the membrane. The membrane shall be protected against damage from reinforcement and site traffic by a layer of cement sand screed of 50mm thickness (maximum aggregate size 6mm may be used at the discretion of the Engineer) over one layer of 5mm thick SBS modified bituminous membrane.
9.6 PROTECTION OF SUBSTRUCTURE [Cont'd]
9.6.1 Horizontal Surfaces [Cont'd]
The area of the membrane laid at any one time should not exceed that which can be protected by screed in the same period. Care should be exercised in the sequence of laying screed to ensure that the membrane laid is not damaged due to site traffic or other trade works or any other reason.
An extra overlap of spray of minimum 300mm of the horizontal membrane shall be left to carry up vertical surfaces to maintain the continuity of the membrane and shall be protected as above.
The concrete surfaces to which the membrane is to be applied shall be cleaned of all grease, oil, dust, loose material, etc. and shall present a sound surface, free of all sharp protrusions. All imperfections like honeycombing, depressions, hollows, etc. shall be made good prior to application of the primer and membrane.
9.6.2 Vertical Surface :
The concrete surfaces to which the membrane is to be applied shall be cleaned of all grease, oil, dust, loose material, etc. and shall present a sound surface, free of all sharp protrusions. All imperfections like honeycombing, depressions, hollows, etc. shall be made good prior to application of the primer and membrane.
The vertical surface also shall be primed with a primer recommended by the manufacturer of the membrane. Vertical surfaces shall also be provided with double layer of 5mm thick SBS modified bituminous membrane such as ‘Dulas-250-QP’ from “Duproof” or approved equal, fully torched on to the surfaces. The extra portion of 300mm of the horizontal membrane left shall be turned up after removal of formwork and wrapped on to the vertical primed surfaces. The continuity of the membrane shall be maintained by minimum laps of 150mm all around. The membrane on the exposed external vertical surfaces shall be carried up to a minimum of 150mm above the finished ground level (i.e., side walk, road surface, paving, etc.) and tucked into a continuous, purpose made groove in the substructure and secured firmly with approved sealant / mastic, recommended by the manufacturer of the membrane. All vertical surfaces of membrane embedded in backfill shall be additionally protected by providing additional 6.5mm thick 'Bituboard' (from "Duproof" or approved equal) protection board in vertical face before backfilling.
The membrane shall be further turned and laid on to other horizontal primed surfaces that need to be applied with the membrane. All such horizontal surfaces shall be protected by a layer of cement sand screed of minimum 50mm thickness over bituminous membrane system.
9.6 PROTECTION OF SUBSTRUCTURE [Cont'd]
9.6.3 Properties of Single Layer 5mm Thick SBS Waterproofing Membrane ‘Dulas-250-QP’ :
The 4mm thick membrane shall exhibit the following characteristics :
Property Characteristics Method of Test
Softening Point R & B > or = 120°C ASTM D 36-76
Dow penetration @ 25°C 30 - 40 dmm
Longitudinal
Transversal ASTM D5-73
Tensile strength
at break 1000N/5cm. 750N/5cm. UEAtc
Elongation at break 50 - 65% UEAtc
Tear strength 220 / 200 N UEAtc
Dim. stability at
28 days at 70°C ± 0.5% ± 0.5% UEAtc
Water pressure
resistance 400 KPa DIN 16935
Water vapour
transmission < 0.50G/m²/24 hrs. ASTM E96
Behavior in water
(absorption) < 0.15% ASTM D570
Static punching resistance,
steel ball diameter 10mm
(0.39") applied load which
damages the membrane On rigid support L4/I3 UEAtc
Rigid or soft support
after 24 hrs. On soft support > 25 kg
Wherever indicated on Drawings, mineral chipping faced membrane 4mm thick shall be provided. The membrane shall have the same characteristics as specified above.
9.6.4 Protection to Ground Slab - Polythene sheet :
Building concrete for base slabs, ramps, steps and the like which are in contact with soil shall be protected by an approved polythene sheet of 1,000 gauge laid on building concrete as detailed on the Drawings or as directed by the Engineer. The continuity of the sheet shall be maintained by minimum laps of 300mm secured by approved adhesive where necessary and/or as directed by the Engineer.
9.6 PROTECTION OF SUBSTRUCTURE [Cont'd]
9.6.4 Protection to Ground Slab - Polythene sheet [Cont'd]
Polythene sheets shall be provided to areas as indicated on the drawings in transparent colour. Polythene sheets shall be manufactured from 100% prime first grade quality resins to BS 6515:1984. Materials manufactured from recycled, off specification or waste materials shall not be accepted.
The polythene sheet shall exhibit all the characteristics of BS 6515 and the Contractor shall produce necessary test certificates to the Engineer to prove the same. Overlaps shall not be less than 300mm and shall be sealed together using an approved adhesive or tape. The material shall be supplied, stored and installed in accordance with the manufacturers written instructions.
9.6.5 Concrete Cover to Reinforcing Steel :
Cover to reinforcement shall generally be in accordance with the relevant British Standards, or as shown on the Drawings.
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