WATER PROOFING WORK -  METHOD STATEMENT

1.    OBJECTIVE:

The objective of this method statement is to carry out the Water-proofing Works by meeting the technical specification and complying with Standards.

2.    SCOPE:

The scope of this method statement includes at all areas at CTSIL, CTSIL site while executing it in accordance with Technical specifications.

3.    REFERENCE 

·         IS-Codes

·         Technical Specification

4.    TOOLS AND TACKLES

·         Preprufe100S,

·         Bitustik ™ 4000,

·         Bituthene 4000, Roller,

·         2 to 3m- Measuring tape,

·         Cuttter.

5.    METHODOLOGY

a)    GRADE SLAB:

           i.        SUBSTRATE PREPARATION:

·         It’s essential to create a sound and solid substrate (layer which has to be waterproofed) to eliminate movement during the concrete pour.

·         Substrate must be regular and smooth with no gaps or voids greater than 12mm

·         Board systems such as timber lagging must be close butted to provide support and not more than 12mm of alignment.

 

          ii.        MEMBRANE INSTALLATION:

·         Place the membrane PE film side to the substrate with particulate layer side up, facing the concrete pour.

·         End laps should be staggered to avoid build-up of layers.

·         Accurately position succeeding sheets to overlap the previous sheet 75mm along the marked selvedge.

·         Ensure the underside of the succeeding sheet is clean, dry and free from contamination before attempting to overlap.

·         Peel back the plastic release liner from between the overlaps as the two layers are bonded together. Ensure a continuous bond is achieved without creases and roll firmly.

 

b)    END LAPS AND CUT EDGES:

·         Overlap all roll ends and cut edges by a minimum 75mm and ensure the area is clean and free from contamination.

·         Remove all floating particulars from the surface of the Perprufe 100S by brush.

·         Apply MS fixer along a 75mm strip on first membrane granular surface roll end.

·         Use metal spatula to spread MS fixer covering 75mm X 1m surface in a homogeneous way.

·         Ensure that T-junctions need 12-15mm wide strip of MS fixer to fill transition gap.

·         Overlap the other end roll lap for 75mm directly on MS fixer prepared surface and roll firmly to ensure complete adhesion without creases or voids.

 

c)    INTERNAL AND EXTERNAL CORNERS:

·         Internal and external corners should be formed as shown in the diagrams below.

·         Ensure that all laps/cut edges are minimum 75mm, sealed with MS fixer and well rolled. Ensure 3D corners are treated with MS fixer. 

 

d)    PENETRATIONS:

·         To seal around the penetrations such as service pipes, pile heads, lighting conductors, etc., mark and cut membrane tight to the penetration. If the membrane is not aligned within 12mm of penetrations apply Perprufe tape lapped onto the membrane and butted tight to the penetration

·         For pipe penetration, wrap the pipe with Preprufe tape. Mix and apply Bituthene LM around the penetrations using fillet to provide a water tight seal between the Preprufe100S membrane and tape.

 

e)    INSTALLATION – VERTICAL:

·         Apply the membrane with white plastic face against the substrate.

·         Mechanically fasten the membrane vertically using flat headed fixings appropriate to the substrate.

·         Membrane shall be installed in any convenient length.

·         Secure the top of the membrane by fixing 50mm below the top edge.

·         Use fixings at typically 600mm centres to secure the membrane flat.

 

f)     INSTALLATION – DOUBLE SIDED FORM WORK

           i.           WOODEN FORMWORK:

·         Apply the membrane with the thick HDPE face against the formwork.

·         Cut lengths of membrane to height of shutter less than 50mm.

·         Align the first piece of membrane against the shutter edge and 50mm below the top of the shutter.

·         Nail the membrane in place of the top of the shutter using 40mm galvanised clout nails @300mm c/c. the nail heads should be left protruding a minimum 20mm.(This will enable encapsulation of the nail head when the concrete is poured).

·         At the middle and bottom of the shutter cut and apply 150mm X 150mm square patches of Bitustik™ 4000 double sided bituminous tape to both edges of the membrane.

·         The Bitustik ™ 4000 patches will partially adhere the membrane to the formwork and keep it flat during the concrete pour.

·         All edge laps should be formed using the self- adhesive selvedge on the membrane.

·         Any cut edge laps and end laps should be executed with MS fixer adhesive.

·         Place shutter, pour and vibrate concrete.

·         Remove formwork when concrete has a minimum strength of 10N/mm2.

·         After removal of formwork.

§  Use hammer to bend all protruding nails flushing in membrane surface.

§  Fill tie rods holes with BETEC® NSM mortar, allow 48 hours to dry then prime with B2 primer and cover with cut patches of Bituthene 4000 selfadhesive membrane, 150mm X 150mm.

§  Lap Preprufe membrane at bottom of wall to slab edge membrane using cut strips of Bituthene 4000 self-adhesive membrane, 300mm wide.

§  Form agreed termination detail at ground level using Bituthene LM.

 

g)    REMOVAL OF FORMWORK:

·         Preprufe membranes can be applied to removable single and double sided formwork, slab perimeter formwork, pile caps, etc. 

·         Once concrete is poured the formwork must remain in place until the concrete has gained sufficient compressive strength of 10N/mm2 is recommended prior to stripping formwork supporting Preprufe membranes

6.    INSPECTION METHODOLOGY 

·         Check whether method of waterproofing is as recommended by consultant and proper application methods.

·         Check whether all the drawings with relevant details for water proofing treatment is available with the site staff.

·         The detailed instructions of waterproofing should bear the signature of the consultant.PVC water stoppers must be ensured at the junction of all joints in the water retaining structures like tanks, swimming pools etc.

·         The area should be inspected before placing any reinforcing steel.

 

7.    RESPONSIBILITIES.

·         Construction Manager: He shall be responsible for overall management of construction activities.

·         Site Engineer: He shall be responsible for Executing in safe work method as per drawings and guide the supervisors and work men.

·          Site Supervisor: He shall be responsible managing all plant and machineries and labour and safety of the workers

·         QA/QC In charge: He shall be responsible for ensuring the quality of work as per the specifications and standards.

·         HSE Manager/Engineer: He shall be responsible for assisting to engineer/supervisor to ensure the safety of workers during the progress of work. Safety inductions of each staff and workers shall be done and daily PPE check to be done and tool box talk shall be carried out before the start of work. General safety awareness as well as particular safety precautions and guidelines for activity to be carried out in that particular day shall be discussed. 

·         Stores officer: He shall be responsible for storing of all materials. Also responsible for maintaining the record of incoming and outgoing and up to date stock details of materials.