Below is a detailed legal-style overview of what you can do if a neighbor builds on your property without a building permit in the Philippines. This is general information, not a substitute for advice from your own lawyer who can review your documents.

I. The Situation: Two Separate Problems in One

When a neighbor builds on your land without a building permit, you’re dealing with two main issues:

Violation of your property rights (Civil Code / property law); and
Violation of the National Building Code (building permit and safety regulations).

You can—and usually should—address both tracks:

Administrative / regulatory (local government, building official); and
Civil / judicial (court cases to protect or recover your property, demolish structures, and claim damages).

II. Basic Legal Concepts You Need to Understand

1. Ownership and Boundaries

Key points under the Civil Code and land registration system:

Registered owners (Torrens title): If you hold an Original or Transfer Certificate of Title, you are presumed to be the lawful owner of the land described in it.
Technical description and survey: Your title contains bearings and distances; this is the basis for a relocation survey by a licensed geodetic engineer.
Possession vs. ownership: Even if your neighbor has been using the area, that does not automatically make them the owner, especially if the land is registered in your name.

2. Encroachment & Accession (Builders in Good or Bad Faith)

The Civil Code has specific rules when someone builds on another’s land:

Builder in good faith: They honestly (but mistakenly) believe they own the land. The law gives the landowner options, usually:
- Appropriate the improvement after paying necessary expenses; or
- Compel the builder to buy the land (or a portion), under certain conditions.
Builder in bad faith: They know the land is not theirs (e.g., you already warned them, or titles clearly show it). Generally:
- The landowner may demand demolition at the builder’s expense, or
- Keep the improvement without paying for it, plus claim damages.

Determining good faith or bad faith is a factual issue that courts decide based on evidence (warnings, documents, behavior).

3. Building Permit Requirement

Under the National Building Code (Presidential Decree No. 1096) and its IRR:

Almost all constructions (new buildings, extensions, major repairs, alterations, renovations) require a building permit from the Office of the Building Official (OBO) of the city/municipality.
A permit is required even if the owner is building on his own land; all the more if the structure is on someone else’s property.
Only very minor works may be exempt (e.g., very minor interior repairs not affecting structural integrity, fire safety, or utilities).

Building without a permit is an administrative and penal violation, separate from the property dispute.

III. Confirming That the Structure Is Actually on Your Property

Before taking formal action, make sure the structure really encroaches on your land.

1. Review Your Documents

Gather:

Title (OCT/TCT) – get a certified true copy from the Registry of Deeds.
Tax declaration and tax receipts.
Subdivision plan / lot plan (if applicable).
Previous survey or fence plan, if any.

Check if the boundaries match the physical occupation on the ground as far as you can.

2. Commission a Relocation Survey

Hire a licensed geodetic engineer (LGE) to conduct a relocation survey:

The LGE will:
- Use your title’s technical description;
- Re-establish boundary points (mojon); and
- Prepare a relocation plan showing where the neighbor’s structure lies in relation to your lot line.
Ask the LGE for:
- A relocation survey plan signed and sealed;
- A narrative report or certification stating whether there is encroachment, and how much (area or measurement).

This document is crucial evidence for barangay proceedings, the building official, and the courts.

3. Check with the Office of the Building Official (OBO)

Even without using search:

Go to the City/Municipal Engineer or OBO and ask:
- Whether a building permit was issued for your neighbor’s structure;
- For a copy of the approved building permit, plans, and location if any.
If no permit exists, ask about the procedure for filing a complaint.

IV. Initial Practical Steps (Before Going to Court)

1. Talk to Your Neighbor (If Still Early and Safe)

If the relationship allows:

Calmly point out:
- Your title and/or relocation survey; and
- That there appears to be encroachment and no visible building permit.
Ask them to:
- Stop construction temporarily; and
- Join you in verifying boundaries (e.g., another survey with both parties present).

Take note or record (privately, within the law) what was said, dates, and their reaction. This may later prove good faith on your part and possibly bad faith on theirs.

2. Send a Written Demand or Cease-and-Desist Letter

If they continue building:

Prepare a demand letter stating:
- Your basis of ownership (title details);
- That the structure encroaches based on survey;
- That there is no known building permit;
- A demand to stop construction and remove or correct any encroachment within a defined period;
- Your intent to file complaints with the barangay, OBO, and possibly the courts.
Have it:
- Sent by registered mail with return card;
- Or personally served with witnesses;
- Or through a lawyer (which often carries more weight).

Keep the proof of service.

V. Barangay Conciliation (Katarungang Pambarangay)

Before filing most civil or certain criminal cases, disputes between individuals living in the same city/municipality must go through barangay conciliation:

The process is handled by the Lupon Tagapamayapa and Punong Barangay.
It is usually required when:
- Both parties are natural persons (not corporations), and
- They reside in the same city or municipality, and
- The dispute is civil in nature or involves minor offenses.

Steps:

File a complaint at the barangay where:
- The property is located, or
- The parties actually reside (check local practice; often the barangay of the defendant’s residence).
The barangay will summon both parties to mediation.
If unresolved, it may go to the Lupon for conciliation.
Results:
- Amicable settlement: written and signed, with effect of a final court judgment once approved.
- Arbitration award: if both parties agree to let the lupon decide.
- Certification to file action: issued after failure of settlement, a requirement before filing cases in court.

Barangay records (minutes, settlement, certification) become important evidence later.

VI. Administrative Remedies: Complaints for Building Without a Permit

1. Filing a Complaint with the Building Official

You may file a complaint with the OBO or City/Municipal Engineer for:

Construction without a building permit; and/or
Violation of approved plans or zoning/setback requirements; and
If applicable, that the construction encroaches on your lot.

Attach copies of:

Your title;
Relocation survey plan and report;
Photos and videos;
Your demand letter;
Barangay documents, if any.

2. Possible Actions by the Building Official

Depending on their findings, the OBO may:

Conduct inspection of the site;
Issue a Notice of Violation;
Order a Stop-Work / Work Stoppage;
Require the neighbor to:
- Apply for a permit (if structurally and legally feasible); or
- Demolish or correct the structure, especially if:
  - Dangerous or structurally unsound;
  - Non-compliant with zoning and setbacks;
  - Built on public property or easements; or
  - Situated clearly on another’s land (which can be a civil issue but may influence administrative action).

Failure to comply can lead to fines, further administrative sanctions, and even criminal complaints for building code violations.

3. Appeals

Orders of the Building Official can typically be appealed to the Secretary of Public Works and Highways (or relevant authority) and, ultimately, challenged in court (e.g., via petitions or appeals under rules on administrative decisions). A lawyer can advise which remedy and timeline applies in your case.

VII. Civil Court Actions to Protect Your Property

If informal, barangay, and administrative steps do not resolve the problem, you may file cases in court.

1. Forcible Entry and Unlawful Detainer (Ejectment Cases)

Under the Rules of Court (Rule on Summary Procedure):

Forcible entry applies when you were deprived of physical possession by force, intimidation, threat, strategy, or stealth, within one year from unlawful entry.
Building on your property and taking over a portion can be treated as forcible entry if it involves such elements.
Relief can include:
- Restoring you to possession;
- Demolition of the encroaching portion;
- Damages and attorney’s fees.

These cases are filed in the Municipal Trial Court (MTC) and are relatively faster than ordinary civil actions.

2. Accion Publiciana and Accion Reivindicatoria

If more than one year has passed or the dispute involves ownership:

Accion publiciana: recovery of possession (longer-term dispossession, usually filed in the Regional Trial Court).
Accion reivindicatoria: recovery of ownership with delivery of possession and sometimes damages.
These actions can include prayers for:
- Demolition of structures built on your property;
- Damages for unlawful occupation;
- Injunction to stop ongoing construction.

3. Action for Removal of Encroaching Structures

You may file a civil case specifically asking for:

Declaration that the structure is an encroachment;
Demolition of the offending structure;
Damages (rental value, loss of use, moral/exemplary damages if justified);
Attorney’s fees and costs of litigation.

The court will rely heavily on:

Your title and other ownership documents;
The relocation survey;
Testimony of the geodetic engineer;
Photographs;
Earlier demands and barangay documents.

4. Injunctive Relief (TRO / Preliminary Injunction)

If construction is ongoing, your lawyer may ask the court to:

Issue a Temporary Restraining Order (TRO) or Preliminary Injunction to stop construction while the case is being heard.
Courts usually require:
- A bond from the applicant;
- Proof that there’s a clear right being violated and irreparable injury if construction continues.

VIII. Applying Civil Code Rules on Builders in Good or Bad Faith

The Civil Code provides detailed consequences when one person builds on another’s land.

1. Good Faith Builder on Another’s Land

If the neighbor truly believed he was building on his own property, and that belief was reasonable:

The law may require you, as landowner, to choose:
- To appropriate the improvement and reimburse necessary and useful expenses; or
- To compel the builder to buy the portion of land affected (under conditions set by law and jurisprudence).
Courts carefully examine:
- Whether you remained silent while watching them build;
- Whether you promptly protested;
- Whether boundary lines were clear.

2. Bad Faith Builder

If your neighbor knew or was clearly warned that:

The land was yours, and
They proceeded anyway;

then courts usually apply harsher consequences:

You may demand demolition at their expense, or appropriate the structure without reimbursing, and
Seek damages for the wrongful encroachment.

Good or bad faith is not determined solely by their self-serving claim; evidence matters.

IX. Possible Criminal Aspects

Aside from civil and administrative cases, there might be criminal liability, such as:

Violations of the National Building Code
- Building without a permit or in violation of orders can be penalized by fines and/or imprisonment under the Code and local ordinances.
Other possible offenses (depending on facts):
- Malicious mischief (damaging property);
- Other property-related crimes if fraud or deception is involved.

Criminal complaints are typically filed with the police or prosecutor’s office. Whether a case prospers depends on evidence and prosecutorial discretion.

X. Special Situations

1. Inside a Subdivision or Condominium

Homeowners’ associations, subdivision regulations, and condominium bylaws may impose additional rules on building, setbacks, easements, and encroachments.
Disputes inside subdivisions or condos sometimes fall under special housing and land use adjudication bodies (now reorganized), in addition to regular courts.
Often, you must also go through the association’s internal processes and file complaints with them.

2. Easements (Right-of-Way, Party Walls, Light and View)

Not every close construction is “on your property”:

Party walls: Some walls may be presumed common (co-owned) under the Civil Code depending on their location and use.
Easement of light and view, windows, and setbacks: The Civil Code and the Building Code have restrictions on opening windows near boundaries and required distances, as well as firewalls.
Right-of-way: In landlocked properties, a neighbor may claim a legal right-of-way—but that must still be established by law and compensated; it is not a license to build at will on your land.

3. Informal Settlers on Your Land

If the structure is built by informal settlers:

Social housing and relocation laws may affect how and when you can remove them.
Government agencies and LGUs may require coordination for relocation or clearance before demolition.
The basic principle of ownership still applies, but procedures are often more complex.

XI. Documentation and Evidence: What You Should Gather

To strengthen any complaint, always document thoroughly:

Ownership & Property Documents
- Certified copy of your title;
- Tax declarations and receipts;
- Subdivision / lot plans;
- Previous surveys or fence plans.
Relocation Survey
- Survey plan signed and sealed by an LGE;
- Narrative report on encroachment;
- The engineer’s field notes if available.
Photos and Videos
- Take dated photos of:
  - The construction at different stages;
  - The encroaching portion;
  - Landmarks and boundary monuments.
Communications
- Demand letters and replies;
- Texts, messages, emails;
- Barangay notices and minutes;
- Any written promises or acknowledgment by your neighbor.
Government Papers
- Certifications or records from the OBO regarding lack/existence of a permit;
- Inspection reports;
- Orders, notices, or decisions from the building official or local government.

XII. Costs, Timelines, and Strategy

1. Costs to Expect

Professional fees:
- Geodetic engineer;
- Lawyer’s professional fees and acceptance fee;
- Possible expert witnesses (engineers, architects).
Court costs:
- Filing fees, sheriff’s fees, bonds for injunction or demolition.
Incidental expenses:
- Transportation;
- Photocopying and notarization;
- Allowances for witnesses.

2. Timelines

Barangay proceedings: usually a few weeks to a few months, depending on cooperation.
Administrative cases with OBO: timeline varies widely per LGU.
Court cases: months to years, especially if appealed.

Because litigation can be lengthy and costly, many owners weigh:

Whether to settle (e.g., sell or lease the affected area, or agree to adjust the boundary with compensation); vs.
Pursuing full demolition and damages for deterrence and protection of property rights.

The strength of your evidence and the extent of encroachment often determine the more practical approach.

XIII. Preventive Measures for the Future

Fence or demarcate your property (following building and zoning rules).
Keep copies of your title and plans accessible.
When you see early signs of encroachment (markers or footings near the boundary), act immediately:
- Verify boundaries;
- Politely warn the neighbor;
- Put objections in writing if needed.
For new developments nearby, monitor LGU postings for building permits and zoning clearances.

XIV. Final Notes and Practical Advice

Move quickly once you suspect encroachment; delay can:
- Weaken your case (especially for forcible entry), and
- Be used against you to claim good faith or laches (sleeping on your rights).
Use multiple avenues at once:
- Barangay;
- OBO/City Engineer;
- Negotiation;
- Preparation for possible court action.
Consult a local lawyer:
- Have your lawyer review your title, survey, and the specific facts;
- Ask which combination of remedies (administrative, civil, criminal) best fits your situation;
- Get help drafting effective demand letters and pleadings.

You have strong legal tools to protect your property in the Philippines, but asserting those rights effectively requires clear evidence, proper procedure, and often professional assistance.