I. Overview and Importance in Philippine Civil Law

Philippine property law frequently turns on whether a thing is considered an accessory or an accession. The classification matters because it determines, among others, ownership, scope of sale or lease, rights of builders/planters/sowers, rights of possessors, indemnities and reimbursements, tax and registration implications, and remedies when separation occurs. While both concepts reflect the idea that one thing may be tied to another, they arise from different legal bases and produce different effects.

At the most practical level:

Accessories are things intended for the use, preservation, or enjoyment of another thing (the principal), and their juridical relationship is anchored on purpose or destination.
Accessions are things that become part of another by incorporation, attachment, union, or production, and their juridical relationship is anchored on physical/material or juridical integration and the principle that the owner of the principal acquires the accession.

Understanding this distinction requires a firm grasp of (a) the principal thing doctrine, (b) the Civil Code’s rules on accession (accession continua and accession discreta), and (c) the Code’s treatment of accessories in relation to obligations and contracts.

II. Legal Concepts Defined

A. Accessories (Accesorios)

Accessory refers to a thing that is joined to, or is for the service of, a principal thing and is intended by the owner (or by the nature of the relationship) to complete, enhance, maintain, preserve, or facilitate the principal’s use.

Key characteristics:

Dependence in purpose Its value and function relate to the principal’s use or enjoyment.
Existence as a distinct thing It usually retains its own identity and may often be separable without material injury.
Relation is often juridical/intentional Accessory status frequently depends on destination (the will of the owner) or customary association, not merely physical attachment.
Follows the principal in legal transactions—unless reserved As a general property-law and contract-law principle, the accessory is presumed included with the principal when the principal is conveyed, unless the parties stipulate otherwise or circumstances show a contrary intention.

Common examples in Philippine settings

A car key, spare tire, jack, and owner’s manual as accessories to the car.
Remote controls as accessories to an air-conditioning unit or TV.
Built-in appliances may be treated as accessories or as immovables by destination depending on facts (see immovable by destination discussion below).

B. Accessions (Accesiones)

Accession is the mode of acquiring ownership by which the owner of a thing (the principal) becomes the owner of everything that is produced by it or incorporated or attached to it, either naturally or artificially. It is grounded in the maxim that accessory follows the principal—but, crucially, “accessory” here is being used in the broader sense of something that is subordinate to the principal, and the Civil Code then breaks down the concrete rules of acquisition.

Accessions are commonly divided into:

Accession Discreta (Fruits/Products) Acquisition of fruits or income produced by a thing.
Accession Continua (Incorporation/Union/Attachment) Acquisition of things that become part of the principal through:
- natural accession (e.g., alluvion, avulsion, changes in riverbeds, formation of islands),
- industrial/artificial accession (e.g., building, planting, sowing on land; attachment of materials; mixture; adjunction).

Key characteristics:

Rooted in ownership of the principal Ownership of the principal triggers the rule of acquisition, subject to special protections (good faith, indemnities, rights of retention, etc.).
Typically involves physical incorporation or juridical assimilation Many accession rules deal with things that become integrated such that separation is impossible, impractical, or legally disfavored—or separation is allowed only with indemnity/reimbursement schemes.
Civil Code provides detailed remedial frameworks Especially in builder/planter/sower situations and in good faith/bad faith conflicts.

Common examples in Philippine settings

Crops growing on land (fruits), subject to rights of usufructuaries, possessors, lessees, etc.
A house constructed on land (industrial accession), with consequences depending on ownership of land vs. builder and good faith.
Alluvion deposits on riparian land (natural accession).

III. The Core Distinction: Accessories vs. Accessions

A. Basis of the Relationship

Accessory: relationship is based on destination or service—the accessory is meant to serve the principal.
Accession: relationship is based on production or incorporation—the accession is acquired because it is produced by or becomes part of the principal.

B. Mechanism of Ownership Transfer

Accessory: typically transfers by contractual operation or by the presumption that a conveyance of the principal includes accessories, unless excluded. Ownership transfer often depends on the parties’ intent, contract terms, and the nature of the thing.
Accession: transfers by operation of law. The owner of the principal acquires the accession under Civil Code rules, subject to indemnities and special rights.

C. Separability

Accessory: commonly separable without destroying the principal; separation usually does not change the principal’s nature.
Accession: often involves things not easily separable, or which, once attached, are treated as forming part of the principal for legal purposes; even if separable, separation may trigger indemnities or legal consequences.

D. Importance in Disputes

Accessory disputes often arise in sales, mortgages, leases, donations, and succession: what exactly was included in the transfer?
Accession disputes often arise in land/building conflicts, possession and improvements, and riparian property changes: who owns the improvement, the crops, or the added land?

IV. Accessories in Philippine Civil Law Practice

A. “Accessory Follows the Principal” as a General Principle

In Philippine civil law, a recurring doctrine is that what is accessory generally follows what is principal. In contracts involving a principal thing, the presumption tends to be that its accessories are included—unless:

the parties stipulate otherwise,
the accessory is explicitly excluded,
the accessory is owned by another and not legally transferable,
or the nature of the accessory relationship does not justify inclusion.

Practical implications

Sale of a vehicle usually includes accessories needed for its normal use (keys, basic tools, documents where applicable, standard installed equipment), unless reserved.
Sale of a house: whether appliances, fixtures, or built-ins are included depends on classification (movable/immovable by destination) and the contract.

B. Accessories vs. Fixtures vs. “Immovables by Destination”

The Civil Code classifies certain movables as immovables by destination when they are placed by the owner of the immovable for industry or works on the land and are intended to remain. This is where accessory analysis becomes subtle:

A movable may be an accessory in the ordinary sense (e.g., machinery used in a factory).
But it may also be treated as an immovable by destination, which affects mortgages (real estate mortgage may cover it), execution, and registration-related transactions.

Philippine context examples

Sugar mill machinery installed by the owner for industrial exploitation of the land.
Commercial cold storage equipment integrated into a warehouse operation.

The decisive factor is typically the owner’s intention and the relationship of the movable to the immovable’s use.

C. Contract Drafting Consequences

Because “accessory” inclusion often depends on intent, best practice in Philippine conveyancing is to:

attach an inventory/list of included accessories,
specify inclusion/exclusion of fixtures, built-ins, appliances, and improvements,
and clarify whether items are treated as movables or immovables by destination (especially relevant in mortgages).

V. Accessions Under the Civil Code: The Full Landscape

The Civil Code’s accession system is broad. “All there is to know” in a Civil Code sense means recognizing the major branches and the recurring themes: ownership of the principal, good faith vs. bad faith, indemnity, and preference for preservation of ownership with equitable adjustments.

A. Accession Discreta: Fruits and Related Rights

Fruits generally fall into:

Natural fruits (spontaneous products of the soil and young/offspring of animals),
Industrial fruits (produced by cultivation or labor, e.g., crops),
Civil fruits (derived from juridical relations, e.g., rent).

Ownership and entitlement to fruits depend on the underlying legal relationship:

Owner is generally entitled to fruits.
Usufructuary is entitled to fruits during usufruct, subject to obligations.
Possessor in good faith is entitled to fruits received before the possession is legally interrupted; once interrupted, rules shift.
Lessee may have rights to industrial fruits depending on lease terms and applicable rules.
Co-owners share fruits proportionally to their shares unless agreed otherwise.

Why this is “accession” Fruits are a form of accession because the principal produces them; the law treats them as acquired by the principal owner (or the person legally entitled to the benefits of the principal, such as a usufructuary).

B. Accession Continua (Natural): Changes Involving Waters and Land

Civil Code rules on accession include classic natural accession situations, especially relevant in an archipelagic country like the Philippines where river systems and coasts matter:

Alluvion Gradual deposits of soil on riparian land caused by the action of waters generally accrue to the riparian owner, because the increase is gradual and inseparable in practice.
Avulsion When a known portion of land is suddenly detached and transferred elsewhere (e.g., due to floods/typhoons), rules differ from alluvion because the original owner can identify the portion.
Change of river course / abandonment of riverbed When rivers change course, the allocation of old beds and new beds is governed by special rules balancing public dominion concepts and private ownership.
Formation of islands Islands formed in rivers or by changes in water action may be allocated according to rules on river ownership and adjacency.

Philippine context note These rules intersect with concepts of public dominion, easements along waterways, and administrative classifications, so practical disputes often involve both civil and public law dimensions.

C. Accession Continua (Artificial/Industrial): Building, Planting, and Sowing

This is where Philippine litigation most commonly centers.

1. The Basic Scenario: Landowner vs. Builder/Planter/Sower

The general logic:

Land is often treated as the principal.
Improvements (buildings/plantings) may be treated as accessions to the land.
But the Civil Code provides equitable relief to builders/planters/sowers, especially in good faith, because improvements may represent significant investment.

Outcomes depend heavily on:

whether landowner and builder are the same or different persons,
whether the builder/planter/sower acted in good faith or bad faith,
whether the landowner acted in good faith or bad faith,
and whether the improvement can be removed without substantial damage.

2. Good Faith vs. Bad Faith: The Engine of Remedies

Good faith generally refers to an honest belief in one’s right (e.g., builder believes he owns the land or has authority). Bad faith implies knowledge of lack of right or deliberate disregard.

The Civil Code’s remedial policy tends to:

protect the landowner’s ownership,
but prevent unjust enrichment by requiring indemnity for useful/necessary improvements made in good faith,
and impose harsher consequences on bad faith actors.

3. Typical Remedial Options (Conceptual Summary)

In many builder/landowner conflicts, remedies revolve around:

Appropriation by the landowner of the improvement with payment of indemnity (especially if builder acted in good faith), or
Compelled sale of the land to the builder (in particular circumstances recognized in civil law practice), or
Removal/demolition at the builder’s expense (typically where bad faith is present), sometimes with damages.

The precise remedy is fact-sensitive and shaped by the Code’s detailed provisions on accession and possession.

D. Accession Continua (Artificial): Adjunction, Mixture, and Specification (Movables)

The Civil Code also addresses accession among movables—often overlooked but important in manufacturing and commerce:

Adjunction (accessory united to principal in movables) Example: attaching a valuable accessory component to a principal thing. Ownership generally goes to the owner of the principal, with indemnities where appropriate.
Mixture/Confusion When liquids/grains/materials belonging to different owners are mixed; rights are determined by the possibility of separation and whether mixture was voluntary or accidental.
Specification When a person transforms materials belonging to another into a new thing (e.g., crafting jewelry from another’s gold). Ownership and indemnities depend on good faith and relative value of materials vs. labor.

VI. How to Identify the “Principal” and Why It Matters

Both accessories and accessions require identifying the principal thing because:

legal consequences flow from the principal,
the owner of the principal generally enjoys priority.

A. Tests for Determining the Principal

Courts and civil law analysis commonly rely on:

Purpose and intention (which thing exists for the other’s use?),
Value (which is more valuable or significant?),
Identity and independence (which thing can exist independently?),
Physical integration (which is incorporated into which?),
Custom and ordinary usage (how are these things ordinarily regarded?).

B. Common Philippine Examples

Land vs. building: land is usually treated as principal in accession contexts; buildings are typically accessions, though ownership conflicts are handled by specific Code remedies.
Car vs. detachable accessories: car is principal; accessories follow unless reserved.
Industrial land vs. installed machinery: may be immovable by destination and treated as following the immovable in mortgages—depending on owner and intention.

VII. Effects on Sales, Leases, Mortgages, and Succession

A. Sale

Accessories: presumed included with the sale of the principal unless excluded.
Accessions: generally included because they are legally part of or produced by the principal; also includes after-acquired accessions in some contexts depending on the nature of the transaction and the timing of acquisition.

Practical points:

Drafting should specify inclusion of fixtures, improvements, appliances, and rights to fruits if relevant.

B. Lease

Lease disputes often involve:

Who owns improvements introduced by the lessee,
Whether the lessor must reimburse,
Whether improvements may be removed,
Treatment of industrial fruits.

This is where accessory vs. accession interplay emerges: a lessee’s additions may be treated as useful improvements and could be removable if separable and if allowed by contract, but accession rules and possession doctrines influence reimbursement and retention rights.

C. Real Estate Mortgage

Items classified as immovables by destination or integral improvements may be covered by a real estate mortgage, even if originally movable, because the mortgage attaches to the immovable and its accessions/immovables by destination, depending on facts and documentation.

D. Succession

In inheritance, the estate generally includes:

the principal property,
its accessions (including fruits accrued, depending on timing),
accessories associated with the principal, unless excluded by law or testamentary disposition.

VIII. Interaction With Possession and Improvements

Civil law distinguishes:

necessary expenses (for preservation),
useful expenses (increase value or utility),
luxurious expenses (mere pleasure/ornament).

This matters because:

A possessor in good faith may be entitled to reimbursement for necessary and useful expenses and may have a right of retention until reimbursed in appropriate cases.
Luxurious improvements may be removable if no damage is caused, but reimbursement is typically limited or disallowed depending on circumstances.

These doctrines often operate alongside accession rules to reach equitable outcomes.

IX. Remedies and Litigation Posture

A. For Accessory Disputes

Typical issues:

whether an item was included in a sale,
whether it is a fixture or movable,
whether it was reserved,
whether removal constitutes breach or damages.

Remedies commonly include:

delivery of the accessory,
rescission or price adjustment (in proper cases),
damages,
replevin/recovery of possession for movables.

B. For Accession Disputes

Typical issues:

ownership of improvements,
indemnities and valuations,
good faith/bad faith,
right to retain until reimbursed,
demolition/removal.

Courts often require:

factual determination of good faith,
appraisal or valuation evidence,
balancing of equities consistent with the Civil Code.

X. Practical Guide: Quick Classification Framework

Step 1: Ask how the relationship arose

If by intended use/service → likely accessory.
If by production or incorporation/attachment → likely accession.

Step 2: Ask whether ownership transfer depends on contract or law

If inclusion depends on what parties meant or typical inclusion in a sale → accessory analysis.
If inclusion happens automatically by virtue of ownership of the principal, with indemnities → accession analysis.

Step 3: Ask whether it is a fruit

If it’s rent, crops, offspring, produce → accession discreta (fruits), then determine who is entitled (owner/usufructuary/possessor/lessee).

Step 4: If attached, ask if it became an immovable or part of the principal

If it is integrated or treated as immovable by destination → more likely accession/immovable analysis than mere accessory.

XI. Common Misconceptions Clarified

“Accessories and accessions are the same because both follow the principal.” They share a general principle but differ in source of inclusion: accessories often follow by intent/transactional presumption, while accessions follow by operation of law and detailed Code rules.
“Anything attached is automatically an accession.” Attachment is relevant but not always decisive. Some items remain movables; some become immovables by destination; and some attachments still require analysis of intent, separability, and legal classification.
“The builder always owns what he builds.” In Philippine civil law, building on land triggers accession frameworks: the landowner’s rights are central, and the builder’s rights depend on good faith/bad faith and statutory remedies.
“Fruits always belong to the landowner.” Not always. Usufruct, lease, and possession doctrines can allocate fruits differently depending on the juridical relationship and timing.

XII. Conclusion: The Philippine Civil Code’s Coherent Logic

Accessories and accessions both operationalize the Civil Code’s commitment to orderly property relations: the principal thing anchors rights, while the law manages fairness through presumptions (for accessories) and structured indemnities and good-faith doctrines (for accessions). In Philippine practice, the distinction becomes decisive in transactions and disputes involving land, buildings, machinery, and fruits—areas where economic value is often high and where the Civil Code provides nuanced solutions rather than one-size-fits-all rules.