Contract for work: lump-sum price, additional works and day-work; default interest from reminder – partial approval of the contractor's appeal

Facts

The appellant (plaintiff, contractor) is a plastering and painting company ([A. AG] ). The respondent (defendant, counterclaimant, client or general contractor) operates a construction company ([B. AG] ).

On 3 December 2014 the parties concluded a contract for work for plastering on a large-scale development at a lump-sum gross contract price of CHF 1'272'964.96, less 10% discount and 2% cash discount, plus VAT. A bill of quantities was incorporated, and the parties agreed, among other things, rules on day-work (only with prior written approval of the site management, daily submission of work reports; loss of the entitlement to remuneration in case of breach, emergencies excepted).

The plaintiff claimed CHF 998'580.99 plus interest at 5% from 18 January 2016 before the Commercial Court of the Canton of Zurich. The defendant requested dismissal of the claim and filed a counterclaim (CHF 48'667.75, alternatively CHF 158'667.70, plus interest), as well as the surrender of various documents (day-work and daily reports, correspondence, invoices, minutes).

The Commercial Court partially upheld the claim and ordered the defendant to pay CHF 262'815.70 plus interest at 5% from 23 April 2018 (service of the claim). It dismissed the counterclaim. The court fee amounted to CHF 68'000.--, allocated 55% to the plaintiff and 45% to the defendant; the plaintiff had to pay the defendant a reduced party compensation of CHF 4'800.--.

The plaintiff filed a civil law appeal with the Federal Supreme Court and requested the annulment of operative paragraphs 1, 4 and 5, payment of CHF 998'580.99 plus interest from 18 January 2016, and alternatively remittal for the taking of evidence. The respondent requested dismissal; the Commercial Court waived a response.

Points in dispute: (1) additional quantities; (2) additional works Nos. 1–5 (unit prices, character as additional works, offers of evidence); (3) day-work (reports Nos. 28–50 and 58–92); (4) commencement of default interest.

Considerations

Admissibility: This is a final decision (Art. 90 FSCA). For appeals against decisions of cantonal commercial courts there is no requirement of a minimum amount in dispute (Art. 74 para. 2 lit. b FSCA). The Federal Supreme Court examines only violations of law (Art. 95, 96 FSCA), is bound by the facts established (Art. 105 para. 1 FSCA), and objections to the establishment of facts are subject to the strict principle of complaint (Art. 106 para. 2 FSCA); arbitrariness is found only where a decision is manifestly untenable. Appellatory criticism is insufficient.

Additional quantities: The parties agreed a total-price or lump-sum contract (Art. 373 f. CO, Art. 41 f. SIA Standard 118). The existence of a bill of quantities does not turn the contract into a unit-price contract. A party relying on a lump-sum price bears the quantity risk, and quantity deviations from the description of works do not give rise to additional remuneration. The plaintiff did not allege changes ordered (item 3.3.1 Project-specific conditions; Art. 86 SIA Standard 118 not applicable). A claim under Art. 59 SIA Standard 118 or the clausula rebus sic stantibus (Art. 373 para. 2 CO) fails for lack of unforeseeability (expert contractor, strict standard; speculative element inherent in every lump-sum price), for lack of a gross and obvious disproportion between performance and remuneration (overall assessment; only two of six items exceeded 100%), and because the request for an expert opinion was insufficiently substantiated. Whether the notice under Art. 59 para. 3 in conjunction with Art. 25 SIA Standard 118 was timely did not need to be decided.

Additional works: Additional work No. 1 had been paid and was not contested. For additional work No. 2 (white finish in 342 wet rooms, 3'985.59 m²) the plaintiff bears the burden of allegation and proof for a price above the accepted unit price of CHF 11.50/m². The plaintiff did not adequately substantiate the requested price of CHF 27.50/m²; the offer for the additional work had been rejected, and an expert opinion may not serve to complete a deficient presentation of facts. In lump-sum contracts the general market prices are in principle decisive and not price escalation; bills of quantities and price analyses may nevertheless be taken into account (BGE 143 III 545 E. 4.4.4.2). The same works may not be remunerated twice, as both additional works and day-work. Additional work No. 3 (stair stringers): item 1 was insufficiently substantiated; item 2 (additional order) remained general and the order had not been established; item 3 (rounding) lacked the character of additional work, as the rounded transitions were already marked in the execution plan before the contract was concluded. Additional work No. 4 (white finish): the general assertion of an order was not conclusive; the assumption of uniform execution within a development is not unreasonable. The lower court argued inconsistently on one point (dimensions versus self-determined unit prices), but this was not decisive for the outcome, as these were alternative grounds. Additional work No. 5 was not contested.

Day-work: The plaintiff alleged that the work was ordered by the site manager and project manager of the respondent, but named no specific dates, times or persons for the ordering of the individual works, and did not distinguish between urgent works and works artificially put under pressure. It did not…