Renovation & construction
Site geotechnics and foundation risk
A geotechnical investigation describes soil, groundwater and foundation parameters; early evidence helps compare structures and avoid artificially low estimates.
A geotechnical investigation describes ground conditions, water and the parameters needed for foundation design. Early evidence helps compare structural solutions and prevents an estimate from appearing cheap only because the ground risk was excluded.
Treat the design decision as a testable hypothesis
Consider architecture with the market and the cost. The scheme must fit within the permitted volume, serve a buyer and remain buildable within budget. An attractive plan without structural, engineering and commercial review is only a sketch.
Compare each version with the brief: saleable area, common space, vertical circulation, parking, accessibility, energy efficiency and operation. Relate decisions to the full budget. The team should document the price and purpose of every change.
Work in sequence without false precision
Start with groundwater and neighbouring buildings, which constrain feasible solutions. Record alternative interpretations where an investigation or document permits them. Then check whether the investigation points are sufficient and relevant to this project stage.
Turn the implications for foundations and basement levels into tasks, each with an owner, required inputs and the date the next participant needs the result. A timetable without these links looks precise but does not assign responsibility.
Write a decision-ready conclusion
State what is confirmed, what remains conditional and what decision is permitted now. Do not promise a public authority's date or a market outcome. If the range is wide, explain why and what it would cost to narrow it. Make the next payment or commitment conditional on a specific finding where the contract provides for this. The related DNPI planning check gives context but does not replace evidence for the site.
An example without invented numbers
One extensive dossier does not establish groundwater or the effect of adjoining buildings. A shorter one documents the investigation points and connects foundation and basement effects to budget and programme. The second supports the base case; the first remains an option pending evidence.
Red flag: without geotechnics, a fixed price for below-ground works often hides exclusions. Pause before the next commitment, seek a site-specific conclusion and update the model. A retention, guarantee or exit right requires contractual agreement; it cannot be imposed unilaterally.
Brief the next design version
The architect records the selected and rejected alternatives and their effects on area and cost. The cost consultant receives the same plans as the commercial team. The brief covers investigation-point sufficiency, groundwater and neighbouring structures, and effects on foundations and basements. If the buyer scenario or a regulatory condition changes, update the brief before issuing the next design package.
