Fixed Price Contracts: No Recovery for Unapproved Additional Costs

The Supreme Court's 2010 ruling in Leighton Contractors Philippines, Inc. v. CNP Industries, Inc. (G.R. No. 160972) provides a clear and important lesson for contractors and project owners alike: in a fixed lump-sum contract, additional costs are recoverable only if the owner authorizes the changes in writing and both parties agree in writing on the added price. This decision reinforces the strict requirements of Article 1724 of the Civil Code and the binding nature of written contracts.

The Facts of the Case

In 1997, Leighton Contractors Philippines, Inc. engaged CNP Industries, Inc. as a subcontractor for the structural steelworks of a fibre cement plant in Laguna. CNP submitted a proposal estimating the project would require 885,009 kilograms of steel at a cost of P44,223,909. Leighton accepted this proposal on July 15, 1997.

The following day, Leighton revised the fabrication drawings for certain structural elements, including the roof ridge ventilation and crane beams. CNP estimated these revisions would require an additional 8,132 kilograms of steel costing P13,442,882—but did not renegotiate the price with Leighton.

On July 28, 1997, the parties signed a subcontract expressly stating that the agreement was on a fixed lump-sum basis and "not subject to re-measurement." The contract placed the responsibility on CNP to derive its own quantities and declared that "[n]o additional payments will be made. for any errors in quantities that may be revealed during the Sub-contract period."

When CNP later demanded payment for the alleged additional costs, Leighton refused. The dispute went to the Construction Industry Arbitration Commission (CIAC), which ruled in favor of CNP. The Court of Appeals affirmed. The Supreme Court, however, reversed.

The Issue

The central question was whether the cost of the additional steel for the roof ridge ventilation and crane beams was included in the fixed lump-sum price, and if not, whether CNP could recover those costs without written authorization from Leighton.

The Ruling

The Supreme Court ruled in favor of Leighton, holding that CNP could not recover the additional costs. Two key principles guided the Court's decision.

First, the scope of work. The subcontract defined the works as the completion of structural steelworks according to the main drawing, technical specifications, and the main contract. The main contract expressly included the drawings for the roof ridge ventilation and crane beams. These items were therefore part of the subcontract works, and CNP was presumed to have estimated the steel quantities needed when it made its offer.

Second, Article 1724 of the Civil Code. Even assuming the revisions constituted additional works, the Court emphasized that recovery of additional costs in a stipulated-price contract is strictly governed by Article 1724. This provision requires two things:

1. Written authority from the owner ordering or allowing the changes in work; and
2. Written agreement of both parties on the increase in price due to the change.

The Court held that compliance with both requisites is a condition precedent to recovery. Neither the authority for the changes nor the additional price may be proved by any other evidence.

CNP argued that Leighton's quantity surveyor, Simon Bennett, approved the cost estimates when he signed the August 12, 1997 progress report. The Court rejected this argument. CNP knew Bennett was not authorized to order changes or approve costs—all project correspondence was addressed to Leighton's project manager, Michael Dent, not Bennett. Bennett signed the subcontract only as a witness. His signature on the progress report merely acknowledged receipt; it did not modify the contract.

Why This Matters

The decision underscores the nature of a fixed lump-sum contract: the contractor bears the risk of errors in measurement and changes in material prices. The contractor estimates project costs based on the scope of work and accounts for probable errors in measurement and price fluctuations. By entering into such a contract, the contractor undertakes that risk.

The parol evidence rule (Rule 130, Section 9 of the Rules of Court) also played a role: when parties reduce their agreement to writing, that writing is considered to contain all the terms agreed upon. Evidence of other terms is generally not admissible, except in limited circumstances—and a claim of oral approval of additional costs is not one of them.

Practical Takeaways

• Get written approval before doing extra work. A contractor who performs additional work without a written change order from the owner risks non-payment, regardless of how necessary or reasonable the work may be.
• Document price changes in writing. Article 1724 requires both written authorization for the change and a written agreement on the additional price. Verbal assurances or signatures on progress reports are not enough.
• Understand the risk in fixed-price contracts. A fixed lump-sum price means the contractor absorbs cost overruns caused by errors in quantity estimates or price fluctuations. Price the work accordingly.
• Check who has authority to approve changes. Only the project owner or a person with actual authority can bind the owner to additional costs. Confirm authority in writing before relying on any approval.
• For owners, ensure contracts clearly define the scope of work. A well-drafted contract that incorporates all relevant drawings and specifications protects against later claims for "additional" work that was actually included in the original scope.

This article is general information and not legal advice. For your specific situation, consult a lawyer or ask ASG Legal AI.