Constructing Brick masonry ventilating chambers as per standard drawing including dressing of beds and sides of chamber to exact profiles 15cm. C.C 1:6:12 (150mm thick) in foundation, first class brick work laid in cement sand mortar 1:5, cement concrete 1:2:4 for reinforced concrete work in slab, 12.5mm thick cement plaster 1:2 rendered with a floating coat of neat cement 1mm thick over exposed brick tablet and inside walls, lime pointing 2:3 on outside complete and as required by the Engineer-In-Charge.