FoundationsBy adminJanuary 9, 20266 min read
Clay, sand, or made ground — the answer changes everything below slab level. A borehole survey costs a fraction of an over-designed foundation, and it occasionally lets us replace expensive piling with a simpler raft. Always test before you design.
What the survey actually tells us
A proper investigation reports bearing capacity at each depth, groundwater level across seasons, contamination, and the shrink-swell behaviour of clays near trees. Our engineer then sizes strip footings, rafts, or piles to the ground as found — not to a worst case assumed from a postcode.
"Test before you design. Guessing underground is the most expensive gamble in construction."
When testing saves real money
On two recent jobs, surveys let us value-engineer piled schemes down to reinforced rafts — saving five figures in each case and three weeks of programme. On a third, the survey found a pocket of made ground the trial pits had missed, and the piling it forced saved the client from settlement cracks within five years. Testing pays both ways.
Order it early
- Commission the survey as soon as the purchase is agreed — results take two to three weeks.
- Share existing drainage searches and tree surveys with the investigation team.
- Let the foundation design wait for the report; never pour to a "provisional" depth.
If your contractor prices foundations without asking about the ground, that price is a guess. Ask us for a fixed, tested design instead.
