This article is for general legal information in the Philippine setting. It discusses common rules and issues under Philippine civil law on succession and co-ownership.

1) The usual situation: “Inherited, but not yet divided”

When a person dies owning real property, the property becomes part of the estate. As a general rule in Philippine succession, the heirs succeed to the decedent’s rights from the moment of death, but until the estate is partitioned, the heirs typically hold the property in co-ownership (“undivided” ownership).

In practical terms:

The land may still be titled in the decedent’s name.
The heirs may not yet have executed a deed of extrajudicial settlement (or an estate court settlement) and partition.
Each heir owns an ideal or proportionate share, not a specific, physically identified portion—unless and until a partition assigns particular areas.

That “undivided” status is the source of most disputes about building.

2) Core rule in co-ownership: each co-owner has rights, but must respect the others

In a co-ownership:

Each co-owner is an owner of the whole in ideal shares.
Each has the right to use and enjoy the property, but only in a way that does not:
1. injure the interests of the co-ownership, or
2. prevent the other co-owners from using the property according to their rights.

Co-ownership law also recognizes that each co-owner may alienate or encumber only their undivided share, not a specific portion—because no one owns a definite portion yet.

3) So—can an heir-co-owner build a house on the undivided property?

Sometimes yes, but it depends on consent, the nature of the construction, and its effect on the other co-owners’ rights.

A. Building with the written consent of the other co-owners: generally allowable

If all co-owners agree (or at least those whose consent is required under the nature of the act), the co-ownership can authorize building, allocate a portion for the builder’s use, and set rules on cost, use, and future partition.

This is the lowest-risk path, especially if:

the house will occupy a defined portion,
the builder will have exclusive use of that portion,
access roads, setbacks, easements, or utilities will be affected.

Best practice: put the agreement in writing and, when possible, align it with a partition plan.

B. Building without consent: legally risky, often a dispute magnet

A co-owner may argue that the improvement is done “at own expense” and does not “alter” the property in a prohibited way. But a house typically:

occupies a definite area,
may block or limit others’ use,
may change the property’s condition and value,
can be seen as an act that effectively appropriates a portion.

Because of these practical effects, building a dwelling without co-owners’ consent commonly triggers claims such as:

injunction to stop construction,
demolition/removal if construction is treated as unauthorized and prejudicial,
partition (to end the co-ownership),
damages or accounting (e.g., if the builder excludes others or benefits from exclusive possession).

Key idea: co-ownership allows use, but not unilateral acts that substantially prejudice co-owners or deprive them of use.

4) A crucial distinction: “acts of administration” vs “acts of ownership/alteration”

In co-ownership, the law distinguishes:

Acts of administration (ordinary management and preservation): e.g., basic repairs, paying real property taxes, routine maintenance, leasing under certain conditions (often subject to rules on majority interests).
Acts of ownership/alteration/disposition (major changes, selling parts, permanent structures, partition-like acts): e.g., building a permanent house that effectively sets aside a portion for one heir’s exclusive benefit.

A permanent residential structure often falls closer to acts of ownership/alteration, especially if it:

prevents others from using that area,
changes access or boundaries,
creates de facto partition,
creates long-term exclusive possession.

When an act requires broader consent and is done unilaterally, co-owners typically have stronger grounds to challenge it.

5) If a co-owner builds anyway: what happens to the house?

A. Ownership of the house vs ownership of the land

A building is ordinarily treated as attached to the land (accession), but co-ownership complicates the situation because:

the land is owned by several persons in ideal shares,
the builder is one of those owners.

Disputes usually focus less on “who owns the house” and more on:

whether the builder must remove it,
whether the builder is entitled to reimbursement/credit,
how the improvement is treated during partition.

B. Reimbursement / credit for improvements

Philippine civil law recognizes that necessary expenses and useful improvements may, in many circumstances, be reimbursable. In co-ownership disputes, outcomes commonly depend on:

good faith (did the builder reasonably believe they had authority or consent?),
objection (did co-owners object early and clearly?),
benefit to the co-ownership (did the improvement increase value without harming others’ use?),
equity in partition (can the improved portion be awarded to the builder with an adjustment?).

A frequent equitable solution in partition cases is:

award the portion with the house to the builder if feasible, and
adjust shares via equalization (payment/offset) or accounting.

But if the structure is clearly prejudicial or built over strong objection, courts can be less sympathetic.

C. Demolition/removal risk

Demolition is not automatic, but it becomes more likely when:

construction was done in the face of express objection,
the structure prevents other co-owners’ reasonable use,
it violates zoning/setbacks/easements,
it was intended to “grab” a portion before partition.

6) Exclusive possession is a flashpoint

A co-owner cannot generally exclude other co-owners from the property. Exclusive possession can trigger:

claims for accounting of fruits/benefits (e.g., fair rental value),
demands for access,
action for partition,
in some cases, damages for wrongful exclusion.

If a co-owner builds a house and then treats the occupied area as exclusively theirs without agreement, other heirs often argue that the builder has effectively appropriated common property.

7) Partition changes everything (and is always available, with limited exceptions)

A defining feature of co-ownership is that any co-owner may demand partition as a rule. Co-ownership is not meant to be permanent.

Partition can be:

extrajudicial (by agreement, through a deed of partition), or
judicial (in court, if heirs cannot agree).

Once partition occurs, each heir gets a definite portion (or proceeds if sold), and then building rights become straightforward—each builds on their own lot.

Important practical point: if someone builds before partition, the partition process becomes harder because the improvement changes valuation, allocation, and fairness.

8) Estate settlement issues: before you even get to “co-ownership management”

Many inherited-property conflicts arise because heirs skip settlement steps.

A. If the property is still in the decedent’s name

Even if heirs are co-owners in principle, dealing with third parties (banks, contractors, LGUs) is difficult when title is still in the decedent’s name.

Typical friction points:

building permit applications may require proof of ownership or authority (often signatures/authorization of registered owners or all heirs),
utility applications may require proof of right to occupy,
future transfer/registration of the house or improvements becomes messy.

B. If there are unpaid estate taxes / transfer steps

Undivided status often persists because estate taxes, BIR requirements, and registry transfer steps are not completed. This increases the risk that any permanent improvement becomes a bargaining weapon in a family dispute.

9) Special situations that can restrict or complicate building

A. Presence of minors, incapacitated heirs, or missing heirs

If an heir is a minor or legally incapacitated, acts affecting their property rights can require stricter safeguards. Any agreement authorizing permanent construction may need careful compliance to avoid later challenges.

B. Surviving spouse and property regime complications

If the property was part of absolute community/conjugal partnership, the surviving spouse’s rights and the estate’s share must be properly determined. What “belongs” to the estate versus the spouse affects who must consent and in what proportion.

C. Agricultural land, tenanted land, land use restrictions

If the land is agricultural or subject to land reform/tenancy issues or zoning limitations, building may require compliance with land use rules and may be restricted in certain contexts. Violations can create separate legal exposure beyond co-ownership disputes.

D. Easements, right of way, setbacks, shoreline, waterways

Building on common property might interfere with legal easements or access rights. Co-owners can challenge construction that blocks an easement or makes the property less usable.

10) Practical “safe paths” if an heir wants to build

Do settlement and partition first The cleanest approach: settle the estate, transfer title to heirs, then partition so the builder owns a definite lot.
If immediate building is necessary: execute a written co-owners’ agreement Common terms include:
- precise area to be occupied (with sketch/survey reference),
- acknowledgment that occupation is temporary pending partition,
- treatment of improvement costs (reimbursement, credit, or waiver),
- access and easement rules,
- what happens if the improved area cannot be awarded to the builder in partition,
- dispute resolution and timelines for partition.
Avoid acts that exclude co-owners Even with a house, issues lessen if:
- other heirs retain reasonable access/use,
- boundaries and access are respected,
- no intimidation, fencing off common areas, or unilateral “no entry” rules.
Document objections or consent early Silence can be misread. If co-owners object, they should do so clearly and promptly; if they consent, it should be written.

11) Common legal actions when heirs disagree

Partition (to end co-ownership)
Injunction (to stop ongoing construction)
Accion reivindicatoria/accion publiciana or similar possessory claims depending on possession issues (often complicated by co-ownership)
Accounting and damages (especially where one co-owner exclusively possesses and benefits)
Annulment/invalidity of unauthorized acts purporting to allocate specific portions as if partitioned

The most durable solution in inherited-property conflicts is usually partition, because it converts a shared, friction-prone relationship into individual ownership.

Bottom line

Yes, an heir who is a co-owner may build in some circumstances, especially with co-owners’ consent and without impairing others’ rights.
Building a house unilaterally on undivided inherited property is legally risky because it often functions like a de facto partition and can prejudice other co-owners’ equal rights to use and enjoy the property.
The ultimate legal pressure valve in these conflicts is partition—and many disputes over “who can build” end up becoming disputes over who gets which portion and how improvements are credited.