ใบอนุญาตุก่อสร้าง (อ.1) ตามพระราชบัญญัติควบคุมอาคาร

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อัปเดตล่าสุดเมื่อ 5 กันยายน 2569

เอ building permit (ใบอนุญาตก่อสร้าง (อ.1), the Or. 1, Aor 1 หรือ construction permit) is the authorisation issued by the local authority under the Building Control Act B.E. 2522 before any building may be constructed, altered, moved or demolished in a controlled area, which today covers almost the whole country. For a foreigner who builds a house on leased or usufruct land, the permit does a second job: issued in the foreigner’s name with the landowner’s consent, it is the main evidence that the house belongs to the foreigner and not to the owner of the land.

What the Building Control Act requires

Section 21 of the Act makes construction without a permit an offence. The application goes to the local authority for the area, the municipality (เทศบาล) in towns or the ออร์ บอร์ ทอร์ in rural sub-districts, and in Bangkok to the district office. It is accompanied by architectural drawings and structural calculations signed by a Thai-licensed architect and engineer, a site plan, a copy of the title deed, the landowner’s ID and, where the applicant is not the landowner, the owner’s written consent to build. The authority has about 45 days to decide.

The permit issued is form Or. 1. It covers only the building described in the drawings, so a change of height, footprint or use needs a fresh application, and it lapses if work does not start within the period stated on it. On completion of a controlled building, the authority inspects and issues a certificate (Or. 6) allowing the building to be used. Ministerial regulations fix setbacks from roads and boundaries, height limits and, in coastal and hillside zones such as Samui and Phuket, distance-from-shore and elevation rules that override anything the seller promised.

Why a foreigner should hold the permit

Thailand has no title deed for a house. Land is registered; buildings are not, except when sold separately or when a superficies is registered. Under Section 146 of the ประมวลกฎหมายแพ่งและพาณิชย์ a building constructed by a person exercising a right over another’s land (a lessee, usufructuary or ผิวเผิน) belongs to that person, not to the landowner. The building permit in the foreigner’s name, the construction contract and the invoices paid from the foreigner’s account are the evidence of that ownership if the marriage ends, the landowner dies or the land is sold.

The permit is also the starting point for the house registration book (ตะเบียน บาอัน), the house number, and the electricity and water connections. A foreign owner obtains the yellow book on the strength of the permit and the completed building.

The common mistake is to let the contractor or the Thai spouse apply in their own name because it is quicker. The permit then says the house is theirs, and reversing that later means a sale of the building at the สำนักงานที่ดิน with fees and taxes. The guide on whether foreigners can own a house in Thailand sets out the sequence: land right first, permit second, construction third.

Building without a permit and what follows

Unpermitted construction is common in resort areas and is a standing risk for buyers of existing villas. The local authority can order work to stop, require alterations within a set period and, where the building cannot be made to comply, order its demolition at the owner’s expense. Fines apply, with a further daily fine while the breach continues, and the officer who signs the order is not interested in whether the current owner built it.

Before buying a house, the checks are that a permit exists, that the building matches the drawings, that the Or. 6 was issued where required, and that the zoning plan allows the intended use. A hillside villa above the height limit or a beach house inside the no-build strip cannot be regularised later. Those checks belong in the การตรวจสอบวิเคราะห์สถานะ, and a missing permit is a reason to reduce the price or walk away.

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ดูเพิ่มเติม: สิทธิ์เหนือพื้นดิน, สิทธิเก็บกิน, Tabien baan, เทซาบัน, ใบอนุญาตก่อสร้างเป็นหลักฐานแสดงความเป็นเจ้าของ และ Construction Law in Thailand.