In the absence of express obligations to the contrary, a building designer is expected to exercise reasonable skill and care. This follows the decision in Bolam -v- Friern Hospital Management Committee (1957) by McNair J. The test is the standard of the ordinary skilled man exercising and professing to have that skill.
A person who professes to have a greater expertise than in fact he possesses will be judged on the basis of his claimed skills. Thus someone obtaining work by pretending to be an architect or chartered engineer may be judged by the criteria that would be applied to assessing the work of the registered or chartered professionals he pretends to be.
A professional claiming greater expertise than his peers may be judged to an accordingly higher standard. In Wimpey Construction UK Ltd -v- D V Poole (1984), it was held that a professional person with special knowledge would be expected to exercise a degree of care in relation to that actual special knowledge. The reasonable skill and care required is measured by reference to the special knowledge and not the lesser knowledge of the ordinary competent practitioner.
Generally the duty of skill and care continues until the designer’s involvement ceases. Thus a designer who visits site may have a duty to correct his design if it is found to be faulty during construction (London Borough of Merton -v- Lowe (1981)). A designer who is dismissed from a project before construction starts may have no ongoing duty of care during construction (T.E. Eckersley & West Water Authority (1988)).
In exercising reasonable skill and care the designer is required to meet the standards of the time. Thus if the designer employs a construction technique which at the time was thought sound but later is found to be flawed, it is unlikely to be held that he failed to exercise reasonable skill and care. However, if he uses untried materials or methods of construction he will be just as liable for design failure as if he makes a mistake in using traditional techniques (Victoria University of Manchester -v- Hugh Wilson & Lewis Womersley and Pochin (Contractors) Ltd (1984).
Exercising reasonable skill and care does not necessarily create a building which is fit for its intended purpose. A fitness for purpose requirement can be expressly incorporated in a building contract. Unless expressly excluded, under English law, a fitness for purpose liability may be implied by statute into a design and build contract. Fitness for purpose does not exclude a requirement to exercise due skill and care but it is usually a more onerous duty. Judging the adequacy of skill and care often relies experts' opinions. By contrast, fitness for purpose may be judged objectively without recourse to experts' opinions.
