A construction works insurance (Bauwesenversicherung) costs, as a rule of thumb in building construction, around 2 ‰ of the construction sum — so for a CHF 800'000 project about CHF 1'600, a one-off payment for the entire construction period. It is an all-risk property insurance on your own building while it is under construction and covers sudden, unforeseen property damage from the groundbreaking to the acceptance. The private policy is not legally required; the cantonal construction-period insurance (Bauzeitversicherung) is mandatory in the 19 monopoly cantons (Monopolkantone) above a certain construction sum — in Bern from CHF 25'000.
Rule of thumb: approx. 2 ‰ of the construction sum in building construction, 3–7 ‰ in civil engineering due to the higher risk. For a CHF 800'000 project, 2 ‰ works out to around CHF 1'600. Industry-typically, the one-off premium for a typical single-family-house project (construction sum CHF 800'000 to 1.2 million) is between CHF 600 and 2'500 — a one-off payment for the entire construction period, not annual. Builder's liability insurance (Bauherrenhaftpflicht) costs a separate CHF 150–350 per year.
As an all-risk policy, sudden, unforeseen property damage to the building is covered: construction accidents (collapse, fall), weather (storm, hail, snow load), fire, vandalism, theft of permanently installed parts, as well as water damage during construction work. Theft of loosely stored materials is optional additional cover. Not covered are damage to neighbouring buildings or third-party property as well as personal injury to third parties — these fall under builder's liability insurance.
Three products, three assets: construction works insurance (property insurance, all-risk) protects your own building during construction, from groundbreaking/excavation to acceptance plus 12–24 months of subsequent cover. Builder's liability insurance (CHF 150–350/year) covers third-party claims. Building insurance (Gebäudeversicherung) protects the completed building after acceptance — in 19 cantons there is a cantonal obligation. A crane damaging the neighbour's carport belongs to liability, the concrete collapse on the building site to the construction works policy.
Construction-period insurance (Bauzeitversicherung) is a special form of building insurance that only applies during the construction phase and covers exclusively fire and natural hazards (storm, hail, flooding, snow load, avalanches, landslides). In Bern (GVB) it is mandatory from a construction sum of CHF 25'000, at two thirds of the basic premium. Zurich (GVZ) requires it on registration of the construction project, St. Gallen (GVSG) for every new build and conversion. It does not cover vandalism, theft and construction accidents.
The sum insured is based on the actual construction costs including own labour plus a 10 % reserve — if insured too low, proportional reduction looms through the underinsurance clause. The deductible (Selbstbehalt) for property damage is typically between CHF 500 and 10'000. A higher deductible, e.g. CHF 5'000 instead of CHF 1'000, lowers the premium noticeably, often by 20–30 %. Clearance and disposal costs are usually co-insured up to 10 % of the construction sum.
Cover ends with acceptance or handover of the keys. Damage whose cause lies in the construction period but which only comes to light afterwards is usually still co-insured for 12 to 24 months via the subsequent-cover clause — explicitly request this clause (24 months). In the case of gross negligence the insurer may reduce the payout (Art. 14 para. 2 VVG), although modern construction works policies frequently expressly waive this. Intent remains excluded in every case.