Regarding Rooftop waterprofing of 02 nos 120 men Barrack ((Trainees Barrackno01 and 2) at CTC (Tand IT)

All APP and loose and de-bonded concrete/screed, loose particles, dirt & should be removed. Roof substrates must be pressure-washed with water with a minimum working pressure of 1,400 psi to be used to and/or remove all dirt, dust, chalk and waste products. Remove algae, mold by using bleach solution or bio wash

All visible hairline cracks on concrete roof screed more than 0.50 mm and not giving hollow sound, should be cut and widen in V shape with mechanical cutter in the size (8 mm W × 6 mm D). Fill cracks with PU Sealant / Hybrid Sealant with suitable gun and smoothed with a putty knife or trowel. Allow sealant to cure a minimum (72 Hrs.) 3 days.

Remove loose and damaged concrete and mortar of roof surface in pockets with mechanical cutter. Clean the roof surface with high pressure water jet to remove dirt and loose particles. Brush applies a bond coat of URP mix in the ratio of 1:1 (URP 1 : Cement 1) by volume to make it lump free slurry when applied on the pre-wet surface. Laid to fall roof screed in correct slope and gradient. Mix URP 10% by weight of cement in (M20) concrete in ratio of 1:1.5:3, i.e., one bag of 50 kg cement : 1.5 times volume of sand : 3 times volume of aggregates : 25 L water. Level the repair mortar and finish with trowel. Moist cure should be done for 7 days. Air cure screed for 4–5 days, before application of roof topcoat coating system.

Hacking and chipping the surface around the rainwater drain outlet up to 25 mm in depth. Apply bond coat of URP in the ratio of 1:1 (URP 1 : Cement 1) by volume over the corners and pipe insert outlet gaps. Filling the gaps around drain mouth with (PMM) polymer modified mortar mixed with URP 10% by weight of cement in the ratio of 1:3. Providing & fixing 100 mm width 225 gsm g/m² Fibreglass Chopped Strand Mat around the periphery of drain mouth of rainwater outlet, sandwiched with Hybrid urethane elastomeric waterproofing component. Apply two thick coats of waterproof coating to completely cover the mesh/fabric and surrounding area.

All loose and de-bonded plaster, loose particles, dirt & should be removed from parapet wall. Wall substrates must be pressure-washed with water with a minimum working pressure of 1,400 psi to be used to and/or remove all dirt, dust, chalk and waste products. Remove algae, mold by using bleach solution or bio wash.

Brush applies a bond coat of URP mix in the ratio of 1:1 (URP 1 : Cement 1) by volume to make it lump free slurry when applied on the pre-wet surface. Then apply cement and sand mortar mix Pidiproof LW+ @ 200 ml per bag of cement. Level the repair mortar and finish with trowel. Moist cure should be done for 7 days. Air cure for 4–5 days before application of topcoat coating system.

Premix Hybrid urethane elastomeric waterproofing components using an electric double-paddle mixer. Apply the first coat of Hybrid urethane elastomeric waterproofing components at a rate of 0.80–0.90 kg/m² without dilution, using a lamb’s wool or cloth roller. While the coating is still wet, roll and embed a 225 gsm Fiberglass Chopped Strand Mat, ensuring full bonding without air bubbles or wrinkles. Allow the first coat to dry for 3–4 hours. Apply the second coat at a 90° angle to the first, overlap the chopped strand mat by at least 5 cm at the joints, ensuring the overlaps are sufficiently wet to achieve proper bonding. After dry, apply the second coat at 0.70–0.80 kg/m². Apply additional coats as needed to achieve a total dry film thickness of 900–1000 microns, with a total system material consumption of 1.50–1.60 kg/m² over 2–3 coats. The material has the following technical properties: Tensile Strength ≥ 18 N/mm² as per ASTM D2370 Crack Bridging Ability: Tear Strength ≥ 160 N/mm as per ASTM D624 Dynamic Crack Bridging as per EN 13251:2016 – No Cracks after 20000 sinusoidal cycles Dynamic Crack Bridging as per ASTM C1305:2016 – Pass, No Crack Pass Low Temperature Flexibility (-20°C after 1000 Hrs. UV) as per ASTM D1970-2021, Shore A as per ASTM D2240-85 Peel Adhesion to Concrete under Wet Condition -24 Hrs. – N as per ASTM C794-14.4 Abrasion Resistance (CS-17 Wheel -1000 Cycle, 1.0 Kg) as per ASTM D4060-7 mg Depth of Water Permeability @ 10 Bar as per EN 12390-8:2019 – Nil Water Migration Resistance as per ASTM D7281-2007 – No Leakage Pass Spread of Flame Class A, complies with the requirements of EN 1351:2016 for a 25-year service life when used with a 225 gsm Fiberglass Chopped Strand Mat as fleece. The system comes with at least 10 years’ waterproofing warranty from the manufacturer. For vertical surfaces and parapet walls, apply and coat with acrylic elastomeric waterproofing components coating system in two coats.

Dismantling of tanks over the roof and disposal of debris near the working site

Supplying and fixing flexible pipe 25 mm as per direction of Engineer-in-charge