Groundworks in the older parts of Northampton are less about what the ground is and more about what somebody already built on it.
Where a plot was a working yard, the ground under it is rarely undisturbed. We find old hardstanding, the foundations of demolished workshops, filled inspection pits and buried service runs that stopped being used decades ago. Some of that is a nuisance and some of it is an advantage, because an existing mass concrete base in the right place can be a genuinely useful thing to build off.
Either way, guessing is expensive. A trial hole before the design is fixed is the single most useful hour spent on a project in these streets, and it turns the biggest variable in a groundworks price into a known figure.
The ordinary considerations sit on top. On shrinkable clay a foundation near a mature tree goes deeper than the standard depth, sometimes considerably. We dig to find bearing rather than to reach a number on a drawing, and the inspector will want to see the same.
Everything is inspected before it is covered. We book the inspections and we do not pour over an unseen trench. Our footings and excavation page explains how we approach foundations and site preparation.