Facts

The appellant, a GmbH (plaintiff in the cantonal proceedings), carried out bricklaying and landscaping work for a prefabricated house which the respondent (defendant) had commissioned from a third party. No written contract existed between the parties. The third party acted towards the plaintiff as the defendant's agent and as site manager. Both parties relied on a cost estimate prepared by the third party before the contract was awarded, which was preceded by a joint inspection of the plot.

The defendant took possession of the house in March 2012 and made payments totalling CHF 140'000.--. On 18 December 2013 the plaintiff invoiced a residual claim of CHF 57'567.05 (final account showing expenditure of CHF 197'567.05 less advance payments).

By action dated 22 May 2015, the plaintiff sought payment of CHF 57'567.05 plus interest and debt collection costs from the District Court of Leuk and Westlich-Raron. The District Court dismissed the action by judgment of 18 January 2019 for lack of sufficient substantiation. The Cantonal Court of the Canton of Valais dismissed the appeal by judgment of 19 September 2019 (C1 19 44).

The plaintiff lodged a civil law appeal with the Federal Supreme Court, requesting that the cantonal judgment be set aside and the action upheld. No responses were invited.

Issue in dispute: whether the plaintiff sufficiently substantiated its claimed remuneration, in particular whether it adequately set out its actual expenditure (remuneration on a time-and-materials basis under Art. 374 CO), and whether the court breached its duty to ask questions under Art. 56 CPC.

Considerations

The Federal Supreme Court reviews only alleged violations of law (Arts. 95 and 96 FSCA) and is bound by the lower court's findings of fact, unless these are obviously incorrect (arbitrary) and correcting the defect could be decisive (Arts. 105 and 97 FSCA). For complaints about the facts, the strict principle of complaint under Art. 106 para. 2 FSCA applies; additional facts must be supported by precise references to the file. The appellant did not meet these requirements, as it largely supplemented the facts established by the lower court and provided only general references to the file.

As regards substantiation, the lower court held that the defendant had disputed the claim and the instruction for additional work. The plaintiff would therefore have had to set out its claim in more detail in its reply, in particular how the expenditure related to the cost estimate. It relied on a payment for expenditure but submitted only five work reports, which together amounted to total expenditure of CHF 105'192.20 and thus lay well below the final account. On this pleaded basis, the expenditure exceeding CHF 140'000.-- could not be reconstructed. The testimony of the party [D.] could not introduce new facts, as the close of the file had already occurred. The testimony of the witness [C.] regarding a contract price of CHF 150'000.-- related to a failed attempt at settlement and cannot be…