Ground investigation: 2026 price, contents and foundation recommendation

A ground investigation – a soil survey – for a detached-house plot in Finland typically costs €800–2,000 in 2026; the average price of completed surveys stays under a thousand euros. The investigation establishes what lies beneath the topsoil – load-bearing gravel, soft clay or bedrock – and what kind of foundations the house needs. Without it, the structural engineer cannot dimension the foundations, so a survey is done for every new house. The price is small relative to what it steers: groundworks and foundations account for 10–15 per cent of the entire construction budget.

What does a ground investigation include?

• 5–6 boring points, most commonly by weight sounding
• Soil-layer sections showing the soil types and the depth of the load-bearing layer
• A foundation recommendation report: bearing capacity, groundwater level and the recommended foundation method
• A site levelling survey with elevation data for the permit drawings

The report also covers frost protection and radon – radon protection is standard in new construction throughout Finland – and travels with the project from permit stage to site as the basis of structural design. When ordering, state the planned building's location and size so the boring points land correctly.

Is a ground investigation compulsory?

The investigation is not permit-regulated work, but the permit for a new residential building – since 2025 the construction permit under the Building Act (rakentamislaki, 751/2023) – in practice requires a foundation method report. Building control and the principal designer define the scope, and practice varies between municipalities. Rule of thumb: always for a new house, case by case for a light outbuilding. The same report dimensions the foundations, assesses frost protection and guides the drainage design.

How do the results steer the choice of foundation?

On load-bearing friction soils – sand, gravel and moraine – a ground-bearing slab is usual, the cheapest type at around €7,000–12,000 including design on easy ground. On a sloping plot, or to manage moisture risk, a suspended ventilated floor is often chosen. On soft clay, silt or peat, the loads go on piles down to a load-bearing layer: piling adds around €7,000 on average to a small house, €20,000–40,000 in demanding cases. Light outbuildings such as carports and stores can often be founded on piers with minimal earthmoving. Without a survey, none of these choices can be justified.

What pushes up the price of a ground investigation?

• Soft clay or silt layers that require sampling
• A deep load-bearing layer and a possible need for piling
• A high groundwater level
• A need for blasting or soil replacement
• A cramped plot where getting the drilling rig in is difficult

Why can a survey under a thousand euros save tens of thousands?

Groundworks for a detached house range from €20,000 to €60,000 depending on the plot, and the difference comes down to the soil. Of two identically priced plots, one can be tens of thousands dearer in groundworks – established for under a thousand euros before purchase. In completed projects, the soil is precisely what explains why one house's ground-bearing foundations cost about €5,000 and another's nearly €29,000.

The most expensive scenario is a wrongly chosen foundation method: building on soft ground without a survey can lead to piling after the fact. Commission the investigation before buying the plot, or immediately afterwards. It does not qualify for Finland's household expenses tax credit, as new-construction work falls outside it.

Ground investigations for hall and outbuilding projects

In a hall project, foundations and groundworks can amount to 30–60% of the total budget – a 1,000 m² hall on clay can require over €150,000 of groundwork including piling. A survey of a hall plot is therefore even more critical than for a detached house, and the same applies to stables and machinery halls: the heavier the building and its floor loads, the more the soil affects the price. A light outbuilding can often be founded more lightly, and the need for a survey is judged case by case.

Checklist for the builder

• Commission the ground investigation before buying the plot, or immediately afterwards.
• Budget €800–2,000; on average you will get away with under a thousand.
• Insist on a foundation recommendation report and a levelling survey with the results.
• Deliver the report to the structural and principal designers before foundation design begins.
• Request groundwork quotes only once the foundation method is settled – otherwise you are comparing guesses.

A ground investigation is the cheapest insurance in a building project. It does not remove problems in the soil, but it removes surprises – and surprises are what cost the most in construction.

• A ground investigation for a detached-house plot typically costs €800–2,000; the realised average is under €1,000.
• Contents: 5–6 boring points, soil-layer sections, a foundation recommendation report and a levelling survey.
• The construction permit (formerly building permit) in practice requires a foundation method report for a new house.
• The report also covers frost protection and radon.
• Groundworks range from €20,000 to €60,000 depending on the soil – commission the survey before buying the plot.
• Piling adds around €7,000 on average to a small house, and €20,000–40,000 in demanding cases.