Assembly works and time-tabling

The assembly of a prefabricated building has been divided into four sequences or stages.

Having completed the preparation of the site, the workmen begin the initial stage. This includes excavating the ground, constructing the concrete foundations, fixing the column base plates and erecting the steel columns. The workmen begin by excavating the ground. This precedes the construction of the concrete foundations because they require solid ground to support them. This is followed by the fixing of the column base plates. Finally the steel columns are erected.

Having completed phase 1, the workmen begin phase 2. This includes fixing the beams and bracing, putting the concrete floors in place, erecting the upper floor steel columns and putting the roof decks in place. The workmen begin by fixing the beams and bracing. This precedes the placing of the concrete floors because they require beams to support them. This is followed by the erecting of the upper floor steel columns. Finally, the roof decking is put in place.

Having completed phase 2, the workmen begin phase 3. This includes erecting the corner units, fixing the horizontal cladding panels, fixing the vertical cladding panels, fixing the balustrade fixing plates and laying the weatherproof roof membrane. The workmen begin by erecting the corner units. This precedes the fixing of the horizontal cladding panels because they are fixed to the corner units. This is followed by the fixing of the vertical cladding panels. Finally, the balustrade fixing plates are fixed and the weatherproof roof membrane is laid.

Having completed phase 3, the workmen begin phase 4. This includes erecting the partitions, installing the services in the ceiling void, fixing the suspended ceilings, decorating the building and laying the floor finishes. The workmen begin by installing the services in the ceiling void. This precedes the erecting of the partitions because the workmen require access to the ceiling void. This is followed by the fixing of the suspended ceilings. Finally, the building is decorated and the floor finishes are laid.

Many trades are involved in the construction of a building. They cannot all work on the building at the same time because some jobs cannot start until others have been completed. Consequently, the time-tabling of jobs is extremely important if the building is to be completed on schedule. Usually the sequence of events in a building program are shown on a bar chart. This is a technique for determining the most efficient way in which events can be time-tabled.

Here is the example of such a bar chart.