Residential construction

Work starts by marking out the column grid and digging pits for the footings. A thin bed of lean concrete (PCC) gives a clean, level base. Mats of reinforcement bars are set on cover blocks so the concrete surrounds them completely, then each footing and its pedestal are cast. Plinth beams link the footings just below floor level, the plinth is filled and compacted, and a damp-proof course under the walls stops ground moisture rising.

Each column starts as a cage of vertical TMT bars held by ties (stirrups). Formwork is fixed around the cage, concrete is poured and compacted, and once it has gained strength the formwork is struck and the concrete is cured with water. Beams frame every floor and carry the slabs and walls to the columns. Bar sizes, spacing and the concrete grade come from the structural engineer’s drawings.

Slabs are cast on shuttering with a mesh of steel bars in both directions, together with the beams below them. The concrete is vibrated, levelled and kept wet while it cures. Its top later receives screed and flooring inside, or waterproofing on the roof.

Walls are built course by course in clay bricks, fly-ash bricks or concrete / AAC blocks, bedded in cement mortar with staggered joints. A reinforced concrete lintel spans every door and window, a sill sheds rain away from each window, and a sunshade (chajja) above it keeps sun and rain off the glass. The ground floor here is left as fair-faced brick to show the bond; the upper floor is plastered and painted.

Water from the municipal main passes a stop cock and the water meter into an underground sump. A pump lifts it through a non-return valve up the rising main to the overhead tank. From the tank a down-take runs down the wall, with a gate valve at the top and a valved branch to the bathroom and the kitchen on each floor. Inside the rooms the lines are concealed in the walls.

The tank stands on a steel frame above the roof so water can leave its outlet freely. A float valve closes the inlet when the tank is full; an overflow, a drain valve, a vent and a tight lid keep it safe and clean. Beside it, a solar water heater warms water for the bathroom.

In the bathroom a pedestal basin with its tap, a concealed shower mixer with an overhead shower, a WC with a wall-mounted cistern and a water heater connect to the concealed hot and cold lines, and a floor trap at the lowest point takes the shower water away. In the kitchen the sink is set in a granite counter over the base cabinets, with its tap on the wall.

The WC’s soil pipe, the floor trap and basin waste upstairs and the kitchen waste downstairs all join a vertical stack outside the wall, held by clamps. The stack rises above the roof to a vent cowl, so water flows freely and trap seals are not sucked dry. At ground level a bend turns it towards the inspection chamber.

Inspection chambers are built wherever drain lines join or change direction, with a smooth channel at the bottom and a removable cover on top. From here the drain runs on to the sewer or the septic system.

Tiles go down once the plumbing is tested and concealed. Floors are laid on a cement–sand bed or tile adhesive and grouted; wet areas get anti-skid tiles over a waterproofed, sloping base, and the bathroom walls are tiled to door height. The kitchen wall behind the counter has a tiled dado that wipes clean, and the entrance porch and steps are tiled to match.

Walls are plastered with a cement–sand mix and cured. Inside, wall putty fills fine pores and is sanded smooth before primer and paint; outside, a weather-resistant exterior paint protects the plaster. Here the upper floor, the columns and the floor bands are painted, while the ground floor shows its brickwork.

The roof is laid to fall towards its rainwater outlets and covered with a waterproof coating or membrane. Where it meets the parapet the layer is turned up the wall over a rounded fillet, so the joint cannot leak. The parapet is capped with coping that sheds water, and a down-pipe takes the rain to the ground. A stair cabin gives access to the roof.

Door and window frames are fixed into the openings, then fitted with shutters, glass, hinges, handles and locks; the ground-floor windows get safety grills. Last of all the porch, paving and garden are finished — and the lights come on.