Quick answer

Usually, no. If a contractor agreed to complete a defined construction project for a fixed or lump-sum price, the contractor generally cannot increase that price simply because labor, materials, fuel, transport, or other inputs became more expensive.

Under Article 1724 of the Civil Code, an increase for additional work generally requires both:

A change in the agreed plans or specifications authorized by the owner in writing; and
A written agreement between the owner and contractor fixing the additional price.

A contractor may also recover more when the original contract itself validly provides for price adjustment, escalation, provisional sums, unit-price measurement, or another applicable payment mechanism. Whether a demand is valid therefore depends on the contract, its incorporated plans and specifications, the nature of the added work, and the written approvals actually issued.

The basic rule for a fixed-price contract

A fixed-price or lump-sum contract ordinarily places the risk of ordinary cost increases and estimating errors on the contractor. Article 1724 of the Civil Code of the Philippines provides that a contractor who undertakes construction for a stipulated price, according to plans and specifications agreed with the landowner, cannot withdraw or demand a higher price merely because labor or materials have become more expensive.

The Supreme Court has applied this rule strictly. In Powton Conglomerate, Inc. v. Agcolicol, it explained that written authorization for the change and a written agreement on the additional price are substantive conditions that must be satisfied before additional costs may be recovered.

Similarly, in Atlantic Erectors, Inc. v. Court of Appeals, the Court held that a contractor under a fixed lump-sum arrangement assumes the risk of measurement errors and ordinary price changes within the agreed scope.

Accordingly, these circumstances do not, by themselves, normally justify a unilateral increase:

Cement, steel, lumber, fuel, equipment, or wages became more expensive.
The contractor underestimated quantities, productivity, or project duration.
A supplier withdrew an earlier quotation.
Exchange-rate movements increased imported-material costs.
The contractor discovered that its profit margin was too small.
Work already included in the plans or specifications turned out to be more difficult or costly than expected.

The owner’s obligation to pay the original contract price remains subject to the contractor’s proper performance and any lawful deductions, retention, damages, or other remedies under the contract.

When the contractor may validly charge more

There is an approved change in plans, specifications, or scope

The clearest exception is a genuine variation from the original work. Examples may include an owner-directed additional room, upgraded finishes, relocated utilities, revised structural details, or work not included in the original plans and specifications.

For Article 1724 to support recovery, there should be:

Written authorization from the owner or a representative who actually has authority to approve the change; and
A written agreement fixing the additional price.

A request to “go ahead” without an agreed price is dangerous for both sides. So is a cost proposal that the owner never accepted. The safest document is a signed change or variation order identifying:

The exact additional or deleted work;
The corresponding drawings and specifications;
The agreed price or method of valuation;
Any adjustment to the completion date;
The effect on progress billings, retention, warranties, and taxes; and
The signatures of authorized representatives.

The Supreme Court has repeatedly treated the two written requirements as conditions precedent. In Salvador v. Court of Appeals, the absence of written authority for the change defeated the claim for additional costs. In Swire Realty Development Corporation v. Specialty Contracts General and Construction Services, Inc., the Court also rejected reliance on unjust enrichment where the contractor had not secured the required written authority and written assent to the additional cost.

The contract contains a valid adjustment mechanism

Not every contract described informally as “fixed price” is identical. The documents may expressly allow adjustments for matters such as:

Owner-approved variations;
Provisional sums;
Allowances subject to actual selection;
Unit-price work measured by actual quantities;
Specified escalation events;
Changes in law or taxes;
Owner-caused suspension or delay;
Differing site conditions;
Currency movements; or
Force-majeure consequences.

The exact wording controls. A contractor cannot simply invoke a clause’s general subject matter; it must establish that the stated trigger occurred and comply with its notice, documentation, valuation, and approval requirements.

An escalation clause also does not necessarily cover extra work. Escalation concerns a change in the cost of performing the same scope, while a variation concerns a change in the scope itself. Different contractual procedures may apply.

The supposed “fixed price” or scope was never actually settled

Article 1724 presupposes an actual stipulated price and definitely agreed plans and specifications. If the parties never fixed the price, left essential plans unresolved, or deliberately used a cost-plus or unit-price arrangement, the dispute may require a different analysis.

In Araneta Center, Inc. v. Megaworld Corporation, the Supreme Court explained that Article 1724 does not make a disputed price immutable when the necessary stipulated price and definitely agreed plans and specifications were absent.

A label such as “lump sum” is important but not always conclusive. The complete contract documents—including the proposal, bill of quantities, drawings, technical specifications, clarifications, exclusions, addenda, and correspondence—must be read together.

The owner separately breached the contract

Article 1724 principally addresses withdrawal or an increased price based on higher labor or material costs. It does not erase other contractual rights.

A contractor may have a separate claim if, for example, the owner:

Failed to make a progress payment when due;
Prevented access to the site;
Suspended work without contractual basis;
Supplied defective plans or owner-furnished materials;
Caused compensable delay; or
Directed work outside the agreed scope.

Such a claim is not automatically an “increase in the fixed price.” It may instead be a claim for unpaid billings, damages, delay costs, an extension of time, or another contractual remedy. Entitlement depends on the agreement, proof of breach and causation, timely notices, and adequate evidence of the amount claimed.

The Supreme Court has recognized that Article 1724 does not govern every construction dispute merely because the contract had a stipulated price. In Ong v. Bogñalbal, the dispute concerned alleged nonpayment and abandonment rather than higher labor or material costs, so the general rules on contracts applied.

The parties validly modified or waived a contractual procedure

A written construction contract is generally the law between the parties. Depending on the facts, a party’s conduct may become relevant to whether a particular contractual procedure was modified or waived.

This is highly fact-sensitive and should not be treated as permission to proceed on oral instructions. In Robern Development Corporation v. Quitain, the Court deferred to factual findings concerning the owner’s treatment of numerous change orders under the parties’ agreement. That result should not be read as displacing Article 1724’s written requirements in every case.

Contractors should obtain written approval before doing extra work, not assume that silence, site presence, inspection, partial funding, or eventual use of the work will necessarily establish liability.

What counts as written approval?

The strongest evidence is a formal change order signed by the owner and contractor. Other documents may be relevant, but their legal effect depends on their contents and the signatory’s authority.

Potential records include:

A signed supplemental agreement;
A variation order stating the agreed price;
Approved revised drawings paired with a signed cost proposal;
A written notice to proceed with clearly priced additional work;
Emails or electronic documents that clearly identify the parties, change, and agreed price; and
Minutes or site instructions formally confirmed and accepted by authorized representatives.

A signature by an architect, engineer, project manager, foreman, or employee is not automatically binding on the owner. Check the contract and written delegation of authority. In Atlantic Erectors, a signed progress report did not establish approval where the person who signed lacked authority to order scope changes or approve their cost.

Written approval of a design revision is also not necessarily written agreement to the contractor’s price. Both elements should be clear.

What an owner should do after receiving a demand

Do not ignore the demand, but do not pay or sign an acknowledgment before checking the records.

Ask for an itemized written claim. Require the contractor to identify each additional item, its contractual basis, the approving document, quantities, unit costs, and effect on the schedule.
Compare the claim with the original scope. Review the signed contract, drawings, specifications, bill of quantities, inclusions, exclusions, bid clarifications, and addenda. Work already included in those documents is not transformed into extra work merely because it was omitted from the contractor’s estimate.
Verify authority. Determine who allegedly ordered the work and whether that person had written authority to bind the owner.
Separate genuine variations from cost escalation. An owner-directed change is different from an increase in the contractor’s cost of performing unchanged work.
Inspect and measure the work. Record whether the claimed work was performed, its quantity, condition, and relationship to the original plans. Use an independent architect, engineer, or quantity surveyor where the amount is substantial.
Respond in writing. State which items are accepted, disputed, or require further proof. Avoid broad admissions. Continue paying undisputed amounts according to the contract unless counsel advises otherwise.
Follow the dispute clause. The agreement may require an architect’s determination, negotiation, mediation, arbitration, or another process before formal proceedings.

What a contractor should do before performing extra work

A contractor seeking additional payment should act before incurring the cost:

Give the notice required by the contract within the specified period.
Describe why the instruction changes the original plans, specifications, quantities, or scope.
Submit a detailed quotation and schedule impact.
Confirm that the person approving the change has authority.
Obtain a signed written change order stating the additional price or an agreed valuation method.
Secure any required permit or approval for the revised work.
Keep separate labor, material, equipment, subcontractor, and delivery records for the variation.
Reserve rights in writing if directed to proceed before valuation, but obtain legal advice because a reservation alone may not satisfy Article 1724.

Where immediate work is genuinely necessary for safety or to prevent serious damage, document the condition at once, notify the owner through every contractually recognized channel, and seek an emergency written instruction. Emergency circumstances do not guarantee reimbursement.

Evidence both sides should preserve

Preserve the original electronic files as well as readable copies of:

The signed contract and all annexes;
Original and revised plans and specifications;
Proposals, quotations, bid clarifications, and exclusions;
Notices to proceed and site-possession records;
Change orders and variation registers;
Emails, messages, letters, meeting minutes, and site instructions;
Proof of each representative’s authority;
Daily construction logs and manpower reports;
Dated photographs and videos;
Delivery receipts, invoices, payrolls, and subcontractor billings;
Progress reports, accomplishment measurements, and inspection records;
Payment applications, official receipts, bank records, and withholding-tax documents;
Delay notices, suspension orders, weather records, and revised schedules;
Permits, inspection approvals, and as-built drawings; and
Records showing when the disputed claim was first made and rejected.

Do not alter messages, drawings, dates, or metadata. Export important chats before devices are replaced or accounts become inaccessible.

Important deadlines and notice clauses

Construction contracts commonly impose short deadlines for notifying the owner of variations, delays, differing site conditions, or additional costs. There is no single notice period for every private project. The deadline may be only a few days, and the contract may make timely notice a condition for payment or an extension.

Read the entire claims and change-order procedure immediately. Check:

When the notice period begins;
Who must receive the notice;
Whether email is permitted;
What supporting documents are required;
Whether work must await written approval;
When a detailed valuation must follow;
Whether the architect or engineer must first decide the claim; and
The deadline for mediation, arbitration, or court action.

Separate statutory prescription periods may also apply. As a general Civil Code rule, an action upon a written contract must be brought within 10 years from accrual, while an action upon an oral contract generally has a six-year period. The correct period and accrual date can depend on the actual cause of action, governing statute, arbitration agreement, demands, acknowledgments, and interruptions of prescription. Do not wait for these outer periods if the contract sets earlier claim deadlines.

Government construction contracts

Public procurement follows additional statutory and regulatory controls. For contracts governed by Republic Act No. 12009 and its implementing rules, bid prices for the awarded scope are fixed during implementation.

Section 89 of the official Implementing Rules and Regulations of Republic Act No. 12009 permits consideration of price escalation for an infrastructure project when there is an extraordinary increase in specific construction components, subject to prior GPPB approval. The rule states that the component cost must increase by more than 10% of the unit price of work items, determined against prevailing Philippine Statistics Authority price indices, and that an authorized adjustment is on a no-loss, no-gain basis using the GPPB-prescribed formula.

The same IRR separately regulates change orders and extra work orders. These are not substitutes for ordinary escalation and require compliance with public-procurement authority, funding, approval, and documentation rules.

Because government procurement transitioned from Republic Act No. 9184 to Republic Act No. 12009, the applicable regime may depend on when the procurement began and what the bidding and contract documents specify. A contractor should not submit a private-project-style variation claim without checking the applicable law, GPPB issuances, standard bidding documents, appropriation, and approval chain.

Resolving a construction-price dispute

Start with the dispute procedure in the contract. A well-supported written claim or response should identify:

The contract provision relied upon;
The original scope;
The alleged change or breach;
The written authority;
The agreed or proposed valuation;
The supporting measurements and cost records;
The schedule effect; and
The precise relief requested.

If the dispute cannot be resolved, the Construction Industry Arbitration Commission may have jurisdiction. Under Executive Order No. 1008, the CIAC has original and exclusive jurisdiction over qualifying disputes connected with construction contracts in the Philippines when the parties have agreed to submit disputes to voluntary arbitration. Covered disputes may include payment defaults, contract interpretation, delays, specifications, and changes in contract cost, whether the underlying project is private or governmental.

An arbitration clause need not use perfect wording to have serious consequences. Before filing in court, have counsel determine whether the agreement, incorporated general conditions, or later written submission binds the parties to CIAC arbitration.

Common mistakes

Treating every cost overrun as additional work.
Proceeding on an oral request without agreeing on the price in writing.
Assuming an architect or site engineer can bind the owner.
Signing a revised drawing without stating whether it changes the price or completion date.
Paying a portion of a disputed variation without documenting what the payment settles.
Using “force majeure” as a general label for inflation or commercial difficulty.
Relying only on receipts without proving that the expense related to approved extra work.
Withholding all progress payments because one variation is disputed.
Ignoring contractual notice and dispute-resolution deadlines.
Altering or recreating records after the dispute begins.
Assuming that the owner’s use of completed work automatically overrides Article 1724.
Confusing government price escalation with change orders or extra work orders.

When legal help is urgent

Consult a Philippine construction lawyer promptly when:

Work is being suspended, abandoned, demolished, or covered up;
The owner threatens termination, bond calls, liquidated damages, or takeover;
The contractor threatens to remove installed materials or block access;
A substantial change is being demanded without a signed order;
Someone asks you to backdate or inaccurately describe a document;
A payment certificate, final account, waiver, quitclaim, or release is awaiting signature;
The contract contains a short notice or arbitration deadline;
Defects, safety risks, permits, or structural changes are involved;
A government project requires agency, GPPB, or appropriation approval; or
Court, CIAC, mediation, or formal demand papers have been received.

An architect, engineer, or quantity surveyor can assess scope and valuation, but legal counsel should review entitlement, authority, notices, prescription, and dispute forum.

FAQ

Can the contractor stop work if the owner rejects the increase?

Not automatically. If the increase is based only on higher labor or material costs within the original fixed scope, Article 1724 generally prevents withdrawal on that ground. Stopping work may itself constitute breach. However, contractual suspension rights, nonpayment, unsafe conditions, owner-caused prevention, or another breach may require separate analysis.

Is a verbal change order enforceable?

For additional payment under Article 1724, verbal authorization is generally insufficient. The owner’s authorization and the parties’ agreement on the additional price should both be in writing.

Does an email qualify as writing?

It may be relevant as an electronic document, but it must clearly establish the required approval and agreed price, come from an authorized person, and satisfy the contract’s prescribed procedure. A vague email such as “please proceed” may not establish agreement on cost.

Can the contractor charge for work omitted from its estimate?

Usually not if the work was already included in the agreed plans, specifications, or contractual scope. A fixed-price contractor ordinarily bears the risk of its own estimating error. Ambiguous or incomplete contract documents require a document-specific assessment.

Can the owner request extra work and decide the price later?

The parties may negotiate, but the contractor faces serious recovery risk if work begins before the additional price is determined in writing. The prudent course is to sign a priced change order—or a clearly agreed written valuation mechanism—before execution.

Can the contractor rely on unjust enrichment?

Generally not as a way around Article 1724’s written requirements. The Supreme Court has rejected unjust-enrichment claims where the contractor failed to secure written authorization and written assent to the additional cost.

Does inflation permit automatic adjustment?

No. Ordinary inflation or market increases do not automatically rewrite a private fixed-price contract. An applicable contractual escalation clause or a special legal regime must support the adjustment. Government infrastructure contracts have separate statutory requirements.

Can the original fixed price be reduced?

Yes, where the parties approve deletions or reduced quantities under the contract, or where lawful deductions arise from incomplete or defective work. The valuation and authorization should also be documented in writing.

Is the contractor entitled to both extra payment and more time?

Not necessarily. A change may affect price, time, both, or neither. The change order should expressly address each. Failure to reserve or document the time impact may complicate a later delay claim.

Who decides whether disputed work was originally included?

The answer begins with the complete contract documents. If the parties cannot agree, the designated architect or engineer may have an initial decision-making role under the contract, subject to the applicable dispute process. A court or CIAC tribunal may ultimately resolve contested entitlement and valuation.

Official legal sources

This article provides general legal information, not advice for a particular contract or dispute. Construction claims depend heavily on the signed documents, approvals, evidence, and procedural deadlines. Consult a qualified Philippine lawyer about your circumstances. Sources were checked as of 26 August 2026.