Un arquitecto. los arquitectos diseñan los planos de la casa.
An Architect, an architect helps by designing the layout of the house.
Inspectores. Inspectores aseguran que la casa este firme, y de bien calidad.
Inspectors. Inspectors make sure that your house is stable enough to live in, and that everything is in proper order after construction.
(i can only think of two sorry, but i hope finding a third is much easier?!)