Almost every plot needs a topographical survey, because the design has to sit on real levels and boundaries. Ground investigation follows on most sites, since it determines the foundation design. Beyond that it depends: drainage surveys where connections are uncertain, ecology where there are trees, hedgerows, watercourses or old outbuildings, and asbestos wherever something existing is coming down. We assess the site and tell you what is genuinely needed rather than ordering the full set as a matter of course.