Quick answer

Usually, no. A contractor who agreed to a fixed or lump-sum price for work based on definite plans and specifications generally cannot compel the owner to pay more merely because labor or materials became more expensive, quantities were underestimated, or the contractor’s profit disappeared.

Under Article 1724 of the Civil Code, additional payment for a change in the plans or specifications generally requires both:

The owner’s written authorization for the change; and
A written agreement between the parties fixing the additional price.

The total amount payable can nevertheless exceed the original price when the contract contains an escalation or adjustment clause, the parties execute a valid change order, the stated price was not genuinely fixed, the original scope was not definite, or the contractor proves a separate entitlement arising from the owner’s delay, interference, or breach. Government infrastructure contracts have additional statutory rules.

A demand is not the same as a legal entitlement. The contract, approved plans, change-order documents, authority of the signatories, and reason for the extra cost must all be examined.

The general rule for fixed-price construction

A construction contract is generally treated as binding according to its written terms. Articles 1159 and 1306 of the Civil Code recognize that contractual obligations have the force of law between the parties and permit them to set lawful terms and conditions.

Article 1724 deals specifically with work undertaken for a stipulated price. When the contractor agreed to build according to definite plans and specifications, the contractor cannot withdraw or increase the price simply because labor or materials later cost more.

The Supreme Court has applied this rule strictly. In Baylen Corporation v. Court of Appeals, the Court held that a contractor under a fixed-price, lump-sum contract assumed the risk of increased construction costs where the contract contained no escalation clause. In Leighton Contractors Philippines, Inc. v. CNP Industries, Inc., the Court likewise ruled that a contractor could not recover alleged additional costs without the writings required by Article 1724.

This usually means the contractor bears costs caused by:

Ordinary increases in material prices or wages;
Incorrect quantity estimates;
Failure to include an item already shown in the agreed plans, specifications, or scope;
Low bidding or an inadequate contingency allowance;
Inefficiency, wastage, rework attributable to the contractor, or poor procurement;
Exchange-rate movements, unless the contract provides otherwise; and
Work that the contractor voluntarily performed without securing the required approval and price agreement.

Calling the added amount a “variation,” “reimbursement,” or “actual cost” does not by itself avoid the fixed-price rule.

When the contractor may be entitled to more

1. There is a valid written change order

For additional work arising from changed plans or specifications, Article 1724 normally requires two distinct matters to be established in writing:

The owner authorized the change; and
Both parties agreed on the added price.

The safest document is a signed change order issued before the extra work begins. It should identify:

The changed drawing, specification, or scope;
Added and omitted work;
The agreed amount or a definite method for calculating it;
Any adjustment to the completion date;
Applicable taxes and retention;
The effect on warranties, bonds, and payment milestones; and
The signatures of people authorized to bind both parties.

The Supreme Court has said that the absence of either required writing can bar recovery. A progress report, receipt acknowledgment, site instruction, or signature merely confirming that a document was received may not establish agreement to pay its stated amount. See Leighton Contractors and Powton Conglomerate, Inc. v. Agcolicol.

A later written ratification or settlement may affect particular completed changes, but it must clearly show what was approved and for how much. Payment for one approved change order does not necessarily waive the written-approval requirement for every other change. In Spouses Chung v. Ulanday Construction, Inc., mere tolerance and payment of selected change orders did not make all unapproved change orders payable.

2. The contract expressly permits escalation or adjustment

A private contract may include an escalation formula or another adjustment mechanism. The clause may be tied to:

A specified construction-material or labor index;
A defined percentage increase;
Exchange-rate movements;
Changes in taxes or laws;
Delayed notice to proceed;
Owner-caused suspension; or
A stated extraordinary event.

The contractor must satisfy the clause’s exact trigger, formula, documentation, notice period, and cap. A clause allowing adjustment in one situation does not create a general right to pass every increase to the owner.

3. The quoted amount was not actually an all-in fixed price

Labels are important but not conclusive. A contract may use the words “lump sum” while separately allowing adjustments for provisional sums, allowances, reimbursable items, unit-price work, owner-selected upgrades, or specifically excluded work.

The controlling questions are:

Was there an actual agreed price?
Was the complete scope definite?
Had the parties agreed on the plans and specifications?
Did the contract reserve particular items for later pricing?
Was the offer still valid when accepted?
Did later negotiations materially replace the original scope or price?

In CE Construction Corporation v. Araneta Center, Inc., the Supreme Court explained that Article 1724 makes a price immutable only when there is an actual stipulated price and definitely agreed plans and specifications. The Court found those premises absent in that fact-specific dispute, which involved prolonged negotiations and substantial changes in design, scope, and project conditions.

This exception should not be treated as permission to disregard a clearly executed fixed-price contract. It applies when the supposed fixed price or definite scope was never truly settled, a matter that requires close review of the documents and the parties’ conduct.

4. The owner caused delay or prevented performance

Some claims are not really requests to reprice the original work. They may be separate claims for compensation or damages caused by the owner.

Under Articles 1721 and 1722 of the Civil Code:

If performance requires an act by the owner and the owner delays or fails to perform it, the contractor may be entitled to reasonable compensation, subject to the statutory calculation and proof; and
If work cannot be completed, without the contractor’s fault, because of defective materials supplied by the owner or the owner’s orders, the contractor may claim an equitable part of the compensation for completed work and reimbursement of proper expenses.

Depending on the contract and evidence, similar issues may arise from late site turnover, delayed drawings, repeated suspensions, failure to make required decisions, or nonpayment of due progress billings. The contractor must still comply with contractual notice, recordkeeping, extension-of-time, and claims procedures. Costs must be connected to the owner’s act and proved, not merely estimated after the dispute begins.

5. The parties voluntarily amend or settle the contract

Nothing prevents the parties from negotiating a lawful written amendment. An owner may agree to an increase to obtain a redesign, upgraded materials, accelerated completion, or an amicable settlement.

The contractor cannot impose the amendment unilaterally. Consent should be documented before additional work or payment, especially where the original contract contains a no-oral-modification clause.

6. Performance became extraordinarily difficult

Article 1267 of the Civil Code permits an obligor to seek release, in whole or in part, when a service becomes so difficult as to be manifestly beyond what the parties contemplated.

This is a narrow, fact-dependent doctrine—not an automatic escalation clause. Courts presume that contracting parties assumed the risk of ordinary unfavorable developments. The Supreme Court has warned that an unrestricted doctrine of unforeseen events would undermine the stability of contracts. See Philippine National Construction Corporation v. Court of Appeals.

Article 1267 speaks of possible release from an obligation. It does not generally authorize a contractor to prepare a new price, send an invoice, and treat that amount as binding. A contractor considering this remedy should obtain legal advice before suspending or abandoning work.

Common situations

Situation	Likely result
Steel, cement, fuel, or wages became more expensive	Normally the contractor’s risk under a true fixed-price contract
Contractor underestimated quantities already within the scope	Normally no increase, especially if the contract disallows remeasurement
Owner requested a different layout and signed a change order with an agreed price	Additional payment is generally supportable
Owner verbally requested extra work, but no price was agreed in writing	Recovery is legally vulnerable under Article 1724
Architect issued an instruction	Depends on the architect’s contractual authority and whether the owner’s authorization and additional price were properly documented
Contractor performed work outside the definite original scope	Potentially payable, but Article 1724 and the contract’s change procedure still matter
Contract contains provisional sums or allowances	Final payment may change according to the clause
Owner delayed drawings or access to the site	A separate time-and-cost claim may exist if properly noticed and proved
Contractor simply underbid the project	Not a legal basis to increase the price
Both parties sign a written amendment	The revised price generally governs, subject to law and the amendment’s terms

Do emails or messages count as writing?

Possibly, but do not rely on an ambiguous chat thread.

Under the Electronic Commerce Act, an electronic document may satisfy a writing requirement when it maintains integrity and reliability, can be authenticated, and meets the applicable requirements for an electronic signature. The Rules on Electronic Evidence also require authentication.

An email or electronically signed change order is much stronger when it clearly identifies:

The authorized sender;
The exact changed scope;
The agreed added price;
Express approval rather than mere receipt; and
The date and complete, unaltered communication record.

A message such as “noted,” “please proceed,” or a thumbs-up reaction may not prove that the owner agreed to the claimed price.

What an owner should do after receiving a demand

Request a detailed written claim. Require the contractor to identify the contract clause, drawing revision, site instruction, change order, computation, and person who allegedly approved the cost.
Compare the claim with the original scope. Review the signed contract, bill of quantities, plans, specifications, inclusions, exclusions, addenda, and bid clarifications. Determine whether the item was already included.
Separate genuine changes from contractor mistakes. A requested upgrade is different from an omitted bid item or quantity error.
Respond in writing without accidental admission. State which parts are accepted, disputed, or still being evaluated. Do not sign a completion certificate, waiver, or acknowledgment of debt without understanding its effect.
Continue handling undisputed amounts according to the contract. A disputed variation does not automatically justify withholding every valid progress billing. Conversely, paying part of a claim without recording its purpose can create avoidable factual disputes.
Obtain an independent technical review. For a substantial claim, an architect, engineer, or quantity surveyor can compare the alleged extra work against the approved plans and measure completed work.
Do not order further changes informally. Use one written change-order process for every addition, deletion, substitution, or acceleration instruction.
Avoid immediate termination or site exclusion without advice. Wrongful termination can create a separate damages claim and affect warranties, bonds, permits, and project safety.

What a contractor should do before performing extra work

Check whether the requested work is already included in the original scope.
Give the notice required by the contract within the stated period.
Identify the changed drawing or instruction precisely.
Submit a priced proposal and requested time extension.
Obtain written authorization from the owner or an expressly authorized representative.
Secure written agreement on the added price or contractual valuation method.
Record labor, materials, equipment, delays, and site conditions contemporaneously.
State any reservation of rights in progress billings and completion documents.
Do not assume that silence, site presence, or an architect’s informal direction equals price approval.
Do not suspend or abandon the project solely because the claim is disputed unless the contract and applicable law clearly permit it and proper notices have been served.

Evidence worth preserving

Both sides should keep original and backed-up copies of:

The signed contract and all annexes;
Tender documents, quotations, exclusions, and bid clarifications;
Approved and revised plans and specifications;
Change orders, variation proposals, and amendments;
Emails, authenticated messages, and transmittal records;
Site instructions, requests for information, and meeting minutes;
Daily reports, photographs, videos, and inspection records;
Delivery receipts, payroll records, supplier invoices, and equipment logs;
Progress billings, payment certificates, official receipts, and retention records;
Project schedules, updated critical paths, and delay notices;
Certificates of completion, acceptance, punch lists, and warranties; and
Proof of each person’s authority to approve changes.

Records created while events are happening are generally more persuasive than a reconstruction prepared only after payment is refused.

Common mistakes

Treating every owner request as a payable variation without agreeing on price;
Assuming an architect, foreman, tenant, or family member can bind the owner;
Signing a progress report without stating whether it approves only accomplishment or also the variation price;
Using vague descriptions such as “additional works” without revised drawings or quantities;
Continuing disputed work for months without formal notice;
Confusing ordinary escalation with extraordinary legal hardship;
Withholding all payments when only one item is disputed;
Paying an unsupported claim simply to avoid delay, without a reservation or settlement document;
Altering or deleting project chats and electronic files; and
Waiting for the general legal limitation period while missing a much shorter contractual notice deadline.

Special rule for government infrastructure contracts

Public projects are governed by procurement law in addition to the Civil Code and the contract.

Section 89 of the New Government Procurement Act, Republic Act No. 12009, treats bid prices for the awarded scope as fixed during contract implementation. For an infrastructure project, price escalation may be considered when the cost of specific construction components increases by more than 10% of the unit price of the work items, determined against prevailing region-specific Philippine Statistics Authority price indices. Any adjustment must be:

Authorized on a no-loss, no-gain basis;
Computed using the applicable GPPB formula; and
Approved beforehand by the Government Procurement Policy Board.

The contractor cannot obtain this adjustment merely by invoicing the procuring entity. The governing bidding documents, contract, GPPB guidelines, project schedule, supporting indices, and approval process must be followed.

The law’s IRR took effect on February 25, 2025. Procurement projects published before that date remain governed by Republic Act No. 9184 and its IRR under the transition guidance in GPPB Resolution No. 05-2025. The applicable regime therefore depends on when the procurement was initiated.

Deadlines and dispute resolution

Read the contract immediately. Construction contracts commonly impose notice, substantiation, engineer-determination, negotiation, or arbitration steps long before an ordinary lawsuit would prescribe. There is no single notice period applicable to every private construction claim.

Under Articles 1144 and 1145 of the Civil Code, an action based on a written contract generally must be brought within 10 years from accrual, while an action based on an oral contract generally has a six-year period. The accrual date can be disputed, special laws may apply, and a contract may require much earlier notices. A written extrajudicial demand may interrupt prescription under Article 1155, but it does not necessarily cure a missed contractual condition or revive a claim that has already prescribed.

Construction disputes involving payment, delay, specifications, defects, default, or changes in contract cost may fall within the Construction Industry Arbitration Commission’s jurisdiction when the parties are bound by an arbitration agreement. This applies to both private and government construction contracts under Executive Order No. 1008. The dispute clause should be reviewed before filing in court.

When legal help is urgent

Seek a Philippine construction lawyer promptly when:

The contractor threatens to abandon the site or remove installed work;
The owner threatens termination, takeover, or a call on the performance bond;
A large variation was performed without a signed change order;
Work is being suspended while delay damages continue to accrue;
Either party is being asked to sign a final waiver, quitclaim, or acceptance certificate;
There are allegations of fraud, falsified approvals, unsafe work, or unlicensed contracting;
A government project requires a price-escalation or variation approval;
A contractual notice or arbitration deadline is approaching; or
The project has serious defects, structural risks, or unpaid labor and material claims.

A contractor’s current license may be checked through the official PCAB license-verification portal.

FAQ

Can a contractor charge more because material prices suddenly increased?

Not under an ordinary fixed-price contract merely because prices rose. The contractor needs a contractual escalation clause, a qualifying government-procurement adjustment, a valid written amendment, or another established legal basis.

Is a verbal change order enforceable?

A verbal instruction may help prove that a change occurred, but Article 1724 generally requires written owner authorization and a written agreement on the additional price. Performing the work on a verbal promise creates a serious recovery risk.

Can the architect approve the additional cost?

Only if the contract or another valid authority allows the architect to bind the owner on both the change and its price. Authority to supervise or issue technical instructions does not necessarily include authority to increase the contract sum.

Does the owner’s use or acceptance of the extra work automatically require payment?

Not automatically. Acceptance may be relevant evidence, but it does not necessarily replace Article 1724’s written requirements. The documents and any written ratification must be examined.

Can the contractor stop work when the owner refuses the increase?

Not automatically. If the original work remains covered by the fixed price, unjustified suspension or abandonment may itself be a breach. Any contractual right to suspend for nonpayment or another default must be exercised through the required notices and procedures.

Can the owner refuse to pay the original contract balance because an extra-work claim is disputed?

Not necessarily. Undisputed, properly certified work remains governed by the payment terms. The owner may assert authorized deductions, retention, defects, delay damages, or set-off only when supported by the contract and law.

Is a cost-plus contract subject to the same rule?

A genuine cost-plus, unit-price, or reimbursable-cost contract is not the same as a fixed lump-sum contract. Payment depends on its own pricing provisions, audit records, approved costs, limits, and markups. The contract’s substance—not its label—controls.

This article provides general Philippine legal information, not legal advice for a specific contract or dispute. Outcomes depend on the complete contract, project records, authority of the parties, and applicable procurement or arbitration rules. Sources and current procedures were checked as of August 5, 2026.