How Bilby works
Piling and ground improvement costs
An allowance for a treatment decision
Weak or uncertain soils can produce an allowance for ground improvement or piling. It is a provision for an engineering decision, not a design stating that a particular pile system will work. Piling transfers loads deeper; ground improvement changes the soil’s performance. They can be alternative strategies.
Avoid adding competing solutions
The native profile uses soil family, depth and risk evidence. If both improvement and piling are plausible, it makes one alternative-treatment range: the smaller low allowance, improvement’s expected allowance and the larger high allowance. It does not add both complete solutions. Specialist measures beyond ordinary assumptions require investigation.
Evidence and quantities
The standalone reference can use pile metres; the native risk allowance does not pretend to know a pile layout.
| Input | Unit | Where from? |
|---|---|---|
| Soil family and weak-layer evidence | condition | Ground assessment |
| Depth and risks | m, flags | Inferred soil depth and evidence |
| Treatment severity | class | Native profile rules |
| Pile metres for reference | pile-m | Project value or editable assumption |
| Actual system and price | scope, SEK | Specialist design and quotation |
Two distinct paths
For example, native medium improvement has SEK 20,000 / 50,000 / 80,000 and moderate piling 80,000 / 180,000 / 300,000. Their alternative-treatment combination is 20,000 / 50,000 / 300,000. The separate national piling reference is fixed 25,000 / 45,000 / 75,000 plus pile metres × 700 / 1,100 / 1,800. A retained native or project-specific scope takes precedence; the reference is not added to it.
Illustrative reference piling
A fictional total of 120 pile-metres gives SEK 109,000 low, 177,000 expected and 291,000 high. Expected is 45,000 + 120 × 1,100. This means aggregate pile length, not 120 m of building perimeter or 120 piles. Changing the assumed pile-metres changes this reference; it does not retroactively design the native treatment allowance.
Depth is not a pile design
Deeper weak clay or organic layers can raise severity and investigation needs. Unknown fill and settlement evidence matter. Missing data can widen uncertainty rather than prove that treatment is unnecessary. Mobilisation, access, load, pile type and final driven length can dominate a real offer. Check whether treatment already belongs to house groundworks before adding a separate line.
Method and review
Reviewed 18 October 2026: native groundworks version 2 and 2026 reference catalogue, research date 16 September. Geological maps supply context; geotechnical investigations collect site evidence for design (SGU, Sweco). These links do not verify Bilby’s pile rates.
The review date covers this explanation and its implemented method. Price and data dates are stated separately in the article.