METHOD STATEMENT FOR WATERPROOFING SYSTEM AT SUB-STRUCTURES
CONTENTS
PAGE
1.0 SCOPE
3
2.0 RESPONSIBILITY
3
3.0 MATERIALS & EQUIPMENT
3-4
4.0 WORK PROCEDURE
4-6
4.1 PREPARATION WORKS 4.2 APPLICATION OF WATERPROOFING MEMBRANES 4.3 CURING & PROTECTION 5.0 FIELD QUALITY CONTROL & INSPECTIONS
6-7
6.0
7
1.0
REFERENCE DOCUMENTS
SCOPE This method statement describes the work procedures, quality assurance & quality control for the waterproofing system at sub-structures.
2.0
RESPONSIBILITY
3.0
2.1
Project Manager is overall responsible for all aspects of the works / project.
2.2
Project Engineer & Site Engineers are responsible for proper execution, arrangement, co-ordination & supervision for the quality, safety & delivery of work.
2.3
Project QA/QC Manager & QA/QC Engineers shall ensure that execution team is following this method statement & implementing the site inspection procedures for materials & installation works.
2.4
Safety Engineer will ensure the implementation of safety at work site.
2.5
BMC Qatar W.L.L shall be responsible for the supply of the approved specified materials, necessary tools & equipment, skilled workers & supervision of works according this method statement & project specifications requirements.
MATERIALS & EQUIPMENT 3.1
Waterproofing Material / System 3.1.1
3.0
Dermabit – Elasphalt 4170 – SBS Modified Bituminous Membranes ( As per the approved materials submittal )
3.2
Protection Screed for waterproofing membrane underside of raft foundation. As per approved Design Mix for Grade 20 Concrete.
3.3
Tower Crane with Concrete Bucket
3.4
Wheel Borrows
3.5
Shovels
3.6
Dumpy Level with Stadia Rod
3.7
Cement Bagger Mechanical Mixer
MATERIALS & EQUIPMENT 3.8 Air Compressor 3.9
Aluminium / Wooden Screeder Bar
3.10 Steel / Wooden Trowel. 3.11 Wooden Planks 3.12 Bonding Agent 3.13 Ordinary Portland Cement 3.14 Clean / Potable Water
3.15 Polyethylene Sheets
4.0
WORK PROCEDURES 1.1 Preparation Works 4.1.1 Horizontal Application 4.1.1.1 The formation level of sub-structures should have been cast with 100 mm thick concrete blinding ( Grade 20 Mpa. ) with a minimum of 250 mm. extended beyond the raft foundation The power float finish surface or steel trowel finish of concrete blinding should checked & rectified for any protrusions, depressions & cracks. 4.1.1.2 Site inspection with the consultant shall be arranged after the preparation work has been completed prior to start waterproofing works 4.1.2 Vertical Application 4.1.2.1 Defective concrete surface such as honeycombs, protrusions, unremoved shutters, chipped surface, dented & cracks shall be rectified with appropriate repair material. Under raft blockwork for pipes trenches or blockwork shutters for lift pits & blockwork behind retaining walls should walls should be plastered evenly at the joints & no protrusions on the surface.
4.0
WORK PROCEDURES 4.1 Preparation Works
4.1.2 Vertical Application 4.1.2.2 External corner sharp edges should be chamfered & internal corner lines between horizontal & vertical surfaces have to be provided with 50 mm x 50 mm. cant strip in order not to puncture or damage the waterproofing membranes. 4.1.2.3 Clean the concrete substrates thoroughly by brooming & with compressed air to remove all kinds of debris. 4.1.2.4 Site inspection with the consultant shall be arranged after the preparation work has been completed prior to start waterproofing works
4.2
Application of Waterproofing Membranes
4.2.1 Horizontal Application ( In accordance with the manufacturer’s instructions ) 4.2.1.1 The double layers of Dermabit-Elasphalt 4170 SBS modified bituminuous membranes, 4 mm. thick each, reinforced with 180 gr./sqm. Polyester each shall be torch-applied with 100 mm. wide side laps & 150 mm. wide staggered laps. The upper layer shall have its side laps staggered to those of the base layer. 4.2.1.2 The waterproofing membranes shall be extended 200 mm beyond the perimeter limit of foundation raft, so that to allow enough membrane extension required for proper connection to the vertically waterproofing membranes.
4.0
4.2.1.3
The polyethylene sheet ( 1000 gauge ) shall be laid over the waterproofing membranes. Site inspection shall be arranged as required prior to laying of polyethylene sheet for the laid membranes.
4.2.1.4
The 200 mm. wide membrane extension around the perimeter shall be protected by extra strip of temporary protective board under the screed bed.
4.2.1.5
Protection screed of 50 mm. shall be carefully placed over the laid polyethylene sheets at required level & with wooden trowel finished. surface. Site inspection shall be arranged, as required prior to protection screed.
WORK PROCEDURES 4.2 Application of Waterproofing Membranes 4.2.2 Vertical Application ( In accordance with manufacturer’s instructions ) 4.2.2.1 The concrete surface shall be primed with Bituprimer S, solvent based bituminous primer conforming to ASTM D-41, at an average coverage rate of 4 sqm. / ltr. & left to dry for about 4 to 8 hours depending on prevailing weather conditions. 4.2.2.2 Double layers of Dermabit – Elasphalt 4170 SBS modified bituminous membranes, 4 mm. thick each, reinforced with 180 gr./sqm., polyester each, fully bonded shall be torch-applied with 100 mm. wide side laps & 150 mm. wide staggered laps. The upper layer shall have its side laps staggered to those of the base layer, complete with Bituprimer S solvent based bituminous conforming to ASTM D-41. 4.2.2.3 The vertically applied waterproofing membranes shall be protected with Armoproof semi-flexible bitumen based protection board, 4 mm. thick, torch-bonded with 30 mm. overlaps. 4.2.2.4 The upper ends of waterproofing membranes shall be inserted into 20 mm. x 20 mm. preformed groove & sealed with bituminous mastic, for the proper termination of membranes ends.
4.3 Curing & Protection 4.3.1 During concreting & throughout the initial hardening, the protection screed shall be protected with polyethylene sheets & with the application of water to prevent the early thermal cracks. 4.3.2 The work area shall be closed from traffic during preparation work, concreting / screeding & curing.
5.0 FIELD QUALITY CONTROL & INSPECTIONS 5.1
The necessary site inspections as stated in the work procedures shall be carried out following the site inspections procedures.
5.2
The QC Engineer & Project Engineer will check & monitor the progress of execution of work to ensure that the work process complies with this method statement.
5.0 FIELD QUALITY CONTROL & INSPECTIONS 5.3 Upon completion of every stage of work, a joint quality inspection between QC Engineer / Project Engineer & Consultant’s Engineer shall be carried to check the quality of work. Any unsatisfactory workmanship or defects found, shall be rectified & preventive action shall be taken to prevent occurrence of the same for the subsequent works.
6.0
REFERENCE DOCUMENTS 5.1 Project contract specifications – QCS Section 5, Part 14 5.2 Project contract drawings.
