Building permits explained simply: steps, documents and costs

Every newly built house must have a building permit (form Or.1) before work starts under the Building Control Act. Building without one carries fines, and local officials can order work stopped or the building demolished. Worse, the house can't get a house number or permanent water/electricity meters, and is hard to sell or mortgage

Documents to prepare

• Building permit application (form Kor.1) — available at the district office, municipality or Subdistrict Administrative Organization
• Copies of every page of the title deed (if you don't own the land, a letter of consent from the owner)
• Copies of the applicant's ID card + house registration
• 5 sets of construction drawings — site plan, floor plans, elevations, sections, structure, electrical and sanitary systems
• Structural calculations, with a copy of the calculating engineer's professional license
• Certificates of the designer and site supervisor (architect/engineer depending on building size — some local authorities relax this for houses up to 150 m²; ask in your area)

Steps and timing

Submit documents to the local authority where the land is → officials check the design complies with building control law (setbacks, height, open space, parking) → results within 45 days by law; in practice a typical house often gets approval in 2–4 weeks if no design changes are needed. Fees are hundreds to a few thousand baht depending on area — the permit is valid for 1 year and can be renewed before it expires

Common mistakes

Setbacks are where designs fail most: walls with openings (windows) must be at least 2 meters from the boundary, solid walls at least 50 centimeters (closer requires the neighbor's written consent), and eaves count as part of the building. Designing for this from the start saves a lot of time on revisions. Another point is later extensions — anything over 5 m² also needs a permit