Why this is the most expensive uninsured cost
Repairing foundation damage in the Netherlands typically costs €50,000 to €150,000 — an amount that is usually not covered by standard home insurance, because foundation damage is often seen as gradual wear or a consequence of soil conditions rather than a sudden, insurable event. Financially, that makes it one of the biggest risks you can encounter as a buyer or owner of a Dutch home — and simultaneously one of the least visible, since the damage develops underground before it manifests above ground.
Construction year as the first red flag
A home's construction year is one of the strongest indicators of foundation risk, which is exactly why it weighs so heavily in the Foundation Report's risk indicator. A rule of thumb: the older the home, and the higher the likelihood it's founded on wooden piles, the higher your level of attention should be — especially combined with a location on peat or soft clay:
- Before 1970, and especially before World War II: wooden pile foundations are highly likely across large parts of western Netherlands, particularly on peat subsoil. This is the category where pile rot is most common.
- 1970–1990: a transitional period when concrete piles and improved foundation techniques became more common, but regional differences remain significant.
- After 1990: typically more modern foundation techniques (concrete, steel), with a structurally lower risk of rot-related problems — though subsidence and differential settlement remain relevant even for newer foundations.
Important: construction year indicates the likelihood of a given foundation type, but doesn't determine with certainty which type it actually is. Which brings us to the next point.
Why nobody knows the foundation type for certain — before a survey
A crucial point when interpreting any data-based risk assessment: the actual foundation type of a specific home (wooden pile, concrete pile, steel, floating foundation) is not recorded in any national Dutch dataset. The BAG doesn't track this, and the data that does exist — for example at the Kenniscentrum Aanpak Funderingsproblematiek (KCAF) or FunderMaps — is licensed per municipality and not freely available nationwide. The PlotSense model is explicit about this: foundation type is weighed as an uncertain, estimated input, with a widened uncertainty margin, rather than treated as known with certainty. This is exactly why the Foundation Report includes a reliability note — to indicate when the data-based estimate is solid enough for a firm conclusion, and when it isn't.
Physical signs to check yourself
Beyond construction year and data, there are concrete, physical signs that can point to foundation problems — signs you can check yourself during a viewing:
- Doors and windows that stick or no longer close properly, especially if this occurs in multiple rooms at once.
- Cracks in walls, particularly diagonal cracks near door and window openings, or cracks that widen toward the foundation.
- Sloping floors — check with a spirit level or a rolling ball whether the floor noticeably slopes.
- Sunken thresholds or a noticeable height difference between the front door and street level, or between adjoining parts of the home (for example an extension separating from the main building).
- Leaning facades — view the facade from a distance for verticality; a noticeable tilt is a signal.
- Complaints from neighbours about foundation problems on the same street — soil conditions are often shared locally between adjacent parcels.
None of these signs is conclusive on its own — houses settle and shift for all sorts of reasons — but several signs together, combined with an old construction year and a risky soil context, are reason to look beyond a visual inspection.
What a €50,000–€150,000 repair actually involves
Foundation repair is invasive and expensive because it almost always means replacing or reinforcing (parts of) the existing foundation while the house remains standing on it. Typical approaches include installing new, more deeply driven piles alongside or beneath the existing foundation, underpinning the ground floor, and repairing any cracks and tilting that developed during the process. Costs vary widely depending on the size of the home, the accessibility of the parcel, and how much of the foundation actually needs replacing — hence the wide range of €50,000 to €150,000. This is on top of any additional costs such as temporary housing during the works.
Data screening first, physical survey as the next step
The practical sequence that gets you the most value for your money:
- Step 1 — data screening (€35): order the Foundation Report before making an offer or planning a renovation. Within minutes you get a risk indicator, the underlying data per source, and a reliability note.
- Step 2 — assess the result: with a low risk indicator and high reliability, the risk according to available data is low, and the data screen is usually sufficient as a first filter.
- Step 3 — physical foundation survey if needed: with an elevated risk indicator, or with a low reliability note (indicating the data estimate is uncertain), a physical foundation survey (€600–1,200) is the logical next step — especially if you're about to bid on a pre-1975 home. A foundation survey typically includes a visual inspection, level measurements, and if needed a boring to establish the actual foundation type and the condition of the wood or concrete.
The Foundation Report (€35) is therefore not a replacement for a physical foundation survey (€600–1,200) — it's a cheap, fast first filter that tells you when that investment is worth making, and when it isn't. With a low risk indicator and high reliability, you may save yourself a survey costing hundreds of euros; with an elevated risk indicator, or low reliability, €600–1,200 is a small investment compared to a potential €50,000–€150,000 repair.
Order your Foundation Report at plotsense.app/zoek or read more on the product page (€35).