WATERPROOFING IN BUILDINGS - METHODOLOGY

WATER PROOFING FOR FLAT ROOFS AND SLOPED ROOFS

1.            The surface to be waterproofed should be prepared thoroughly by chipping all cement mortar deposits/ loose material, dust etc. using a chisel, wire and coir brush.

2.            The surface, which is to be waterproofed, should be ponded with water and any dampness / leakage should be marked in the ceiling below the terrace. Wherever leakage persists, 12mm diameter GI nipples should be fixed depending on the depth of dampness, on such weak locations in the ceiling and it is pressure grouted with neat cement slurry admixed with expansive grouting.

3.            ‘V’ grooves should be cut along the concrete / brickwork junctions on joints. Surface cracks if any should be filled with polymer modified diluted solution and also in cutouts, around the sleeves, drain pipe joints and filled with sealant.

4.            Every upturns and pipe outlets should be reinforced with fiber mat between the two coats

5.            Two coats of Acrylic polymer based waterproofing system or equivalent should be applied on terrace and parapet walls. One coat of neat cement mixed with polymer additive should be applied as bonding coat.

6.            A protective screed of 20-25mm thick should be provided with proper slopes. The treated area should be plastered to required slope as per drawing and cured for a minimum of 3-4 days.

7.            To ensure water tightness, the treated area shall be filled with water and tested.

8.            Over the treated surface, weathering course tiles should be laid on the terrace maintaining a proper slope.

WATER PROOFING FOR SUNKEN AREAS/ SLABS

1.            The surface, which is to be waterproofed, should be cleaned thoroughly from all loose material, and dust, using wire and coir brush.

2.            The surface, which is to be waterproofed, should be ponded with water and any dampness/ leakage should be marked in the ceiling below the terrace. Whenever leakage persists, 12mm diameter GI nipples should be fixed depending on the depth of dampness, on such weak locations in the ceiling and it is pressure grouted with neat cement slurry admixed with expansive grouting.

3.            ‘V’ grooves should be cut along the concrete / brickwork junctions on joints. Surface cracks if any should be filled with polymer modified diluted solution and also in cutouts, around the sleeves, drain pipe joints and should be filled with sealant

4.            Two coats of Acrylic polymer based waterproofing system should be applied as a bonding coat on the treated surface.

5.            All joints between the beam and blockwork should be covered with the fiber mat.

6.            Plaster the treated area with neat cement and high grade waterproofing additive to the required slope as per drawing to protect the coating from wear and tear.

7.            The treated area should be subjected for testing by ponding water at least for a depth of 150mm for 24hrs.

8.            The chasing for concealed plumbing, and electrical works should be completed before the start of waterproofing and the chasing must be treated with an agent such as FORMDEX. 

9.            Over the treated area, stone dust should be filled and roughly finished with 75mm thick screed concrete 1:2:4 to facilitate laying of tiles. The screed concrete floor level should be 20mm below the main floor, to facilitate a level difference between main area and toilet after tiling and to prevent toilet water entering the main area.

METHODOLOGY OF WATERPROOFING IN TOILET AND SHOWER/ WASH AREAS USING MUREXIN COMPOUND 

1.            Ensure the cement plastering for all toilet and shower areas are plumb, and at right angles to the facing walls, ceiling and floor levels.  Further the plaster should have an even surface and a slightly rough texture. The flooring during the finishing stage must be adjusted to the slope of screed level set towards water-outlets.  

2.            After sufficient time for setting of plaster, clean the plastered surface using a mason’s brush of all dirt and dust particles. Before each application, the base must be dry and free of all dust-particles and foreign materials.  

3.            Mark out the areas to be waterproofed, with the help of a pencil, measuring tape and spirit levels.  Separate this area from the rest using masking tape.  

4.            Apply the base coat MUREXIN LF as the first coat. This coat is done uniformly using the Masons brush over the entire area. Allow this coat to dry for about 20 minutes. Let the drying process be natural and do not subject the area to any wind-draft. 

5.            During the drying period of the base-coat, the two component sealing material MUREXIN, made up of the powder component and the liquid component should be mixed slowly and evenly in the ratio of 2:1, using the mechanical stirrer (imported from Germany for the purpose).  For example, for every 2 Kg of Powder component mix with 1 Litre of the liquid compound. Stir this mixture slowly and uniformly in to a homogenous mass free of any knots or nodules (Mixing time- 3 minutes).   

6.            Now the well-mixed sealing medium maybe applied uniformly using the 6mm teethed trowels first vertically in all the corners, in the spray areas of the shower area up to a height of 2 meters and in the rest of the toilet area to a height of 0.30 meters. Subsequently the MUREXIN sealing strip (caulking strip) will be placed along the corners and fixed uniformly using the right edged trowel and pressed firmly along the corners.  Now please ensure that the sealing strip –also called the caulking strip, is fixed firmly in the corner ensuring there is no air gap. 

7.            Subsequently the sealing compound is applied uniformly using the 6 mm-teethed trowel ensuring the thickness of the applied layer is maintained evenly at 1 mm. In the region where the pipe connections project from the plastered area, overlap such areas with the strips and apply the compound to fix them.  After sufficient time for drying (About 24 hours), the second layer of 1 mm layer is to be applied thus bringing the total thickness of the application to 2 mm. Now remove the masking tape. 

8.            After allowing about 24 hours for drying, the walls are tiled, using “MUREXIN-Flexi-mortar” adhesive using the 6 mm teeth trowels. 

9.            After the walls are completely tiled, the flooring tiling is also taken up in a similar fashion.  This means repetition of the procedures 1 to 8 before the floor tiles are brought on, so that the flooring is also well water proofed and sealed.

TOOLS TO BE USED BY TRADESMEN

Required tools must be available at site to ensure correct work. Basic tools of the waterproofing gang are:

1.            Dumpy levels

2.            Line dori

3.            Spirit level 

4.            Tube level

5.            Plumb bob

6.            Aluminium straight edge

7.            Trowels

8.            Mason’s brush

9.            Mechanical Stirrer (German)

10.         6mm teethed trowel

11.         Right edged trowel

12.         Finishing boards and sponge

13.         Chipping tools

14.         Hammer

15.         Water barrel

16.         Bitumen roller

INSPECTION METHODOLOGY FOR QUALITY ASSURANCE

1.            Check method of waterproofing is as per recommended by consultant and proper application methods

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

3.            The detailed instructions of waterproofing should bear the signature of the consultant

4.            PVC water stoppers must be ensured at the junction of all joints in the water retaining structures like tanks, swimming pools etc.

5.            The waterproofing supervision job card should be attached.