Renovating or extending a Koh Phangan villa: when you need a permit, a Section 39 bis notification, or nothing

Do I need a permit to renovate or extend a villa on Koh Phangan? It depends on whether the work changes the structure or floor area. Under Section 21 of the Building Control Act B.E. 2522 (1979), anyone intending to construct, alter or remove a building must either obtain a licence from the local competent official or notify the official and proceed under Section 39 bis. This is general information, not legal advice.

What counts as an alteration

Section 4 defines alteration as a change, addition, reduction or expansion of the characteristics, limits, design, shape, proportions, weight or area of the structural elements of a building, so that it differs from the original state. In practice, practitioner sources describe the following as typically needing approval:

• Structural changes — removing load-bearing walls, or altering foundations, beams, columns or slabs.
• Extensions — adding floor area or enclosing a terrace.
• Roof work — changes to the roof frame, weight or form.
• Change of use — for example turning a residence into a shop, restaurant or guesthouse; see the Or.6 use certificate.
• Demolition of part of a building.

Cosmetic work such as painting, retiling, replacing fixtures or updating cabinets is generally reported not to need approval, provided structure and floor area are unchanged. A search excerpt of the Ministerial Regulations compilation also indicates that certain minor changes are exempt, such as changes not adding load to the structure by more than 10%, or changing floor or roof area by no more than 5 m² in total without changing the number of posts or beams. I could not open the regulation text itself, so confirm the exact conditions with the local office before relying on an exemption. A widely repeated 150 m² figure is not a universal exemption.

Two routes: licence or Section 39 bis notification

• Licence — apply to the municipality, sub-district administration (TAO) or district office. The statutory review period is reported as generally 45 days from a complete application, and revisions can extend it.
• Notification (Section 39 bis) — the owner notifies the official with architect and engineer certifications that the work complies with the law, plus plans and calculations. The official issues a receipt, and the notified work may start from the date of that receipt.
• Official review (Section 39 ter) — the official may order corrections within seven days if information is wrong, and has 120 days to raise objections. If none are raised, the work is deemed authorised, except for encroachments on public places or breaches of distance requirements.
• Completion — for notified works, the owner notifies completion in writing so the building can be inspected within thirty days of receipt.

What happens without a permit

• Section 65 — breach of Section 21 is punishable by up to three months' imprisonment, a fine of up to THB 60,000, or both, with a further daily fine of up to THB 10,000 while it continues.
• Sections 40-42 — the official may order work suspended and, for non-rectifiable breaches, order demolition of all or part of the building within a set period.
• Section 67 — ignoring a suspension or demolition order carries up to six months' imprisonment, a fine of up to THB 100,000, or both, plus daily fines.
• A contractor's mistake does not automatically protect the owner — responsibility generally rests with the owner or occupier of the building.

What it means for buyers and owners

• Compare the building to the permit — extensions, enclosed terraces and added floors are the usual discrepancies; see verifying building permits and the due diligence checklist.
• Renovations trigger current rules — an older villa may have to meet today's coastal, hillside and zoning limits; see coastal setback rules and hillside limits.
• Renovated plumbing — septic upgrades fall under a separate rule; see septic and wastewater rules.
• Ask before you start — the local building office decides whether a project needs a licence, a notification or no filing; get that answer in writing.

In short: cosmetic work is generally free of filings, but anything touching structure, floor area, roof or use should go through the local office before work starts. Confirm with a Thai lawyer and the local office, since practice varies by municipality.