The success of a project depends on how faithfully it follows the plan and whether it complies with construction regulations, which is what supervision ensures. Generally speaking, it makes sure that the resulting design matches the planned one. One could wonder why to control something that is done according to a plan? The answer to this question is simple: contractors love experimenting and with offer the service of supervision to avoid such experiments.
The supervision is performed by the same designer who did the initial designing and project documentation. Regular visits to the site allow the designer to make adjustments to blueprints, if necessary, agree the necessary adjustments with the client, consult the contractor and suppliers, order materials and control their timely delivery.