Legal Home Extensions in Chiang Mai — Where to Get Permits and What the Process Involves

Legal Home Extensions in Chiang Mai — Where to Get Permits and What the Process Involves

Extending a home without a permit is a common issue in Chiang Mai that can significantly affect future sale and mortgage processes. This article explains the correct procedure.

Which Extensions Require a Permit

Always requires a permit: Construction of new structures or extensions affecting the building's main structure — new rooms, adding a second floor, new permanent roofing, some types of new fencing

Does not require a permit (minor work): Painting, window replacement, interior renovation not affecting structure, electrical appliance installation (though wiring must be done by a licensed electrician)

Where to Submit the Application

Chiang Mai Municipality (within city limits): Department of Engineering, Chiang Mai Municipality, Vajiravudh Damnoen Road
Sub-district/Provincial Administration (outside city limits): For Hang Dong, San Sai, Mae Rim properties — submit to the responsible local administration for that area

Required Documents

Title deed or ownership document copy; national ID of property owner; construction drawings (must be signed by a licensed engineer or architect); structural calculations (for major works); owner's consent letter if the applicant isn't the land owner

Permit Process

Step 1: Hire engineer/architect to prepare drawings (2-4 weeks); Step 2: Submit documents; Step 3: Await review (20-30 business days); Step 4: Pay fees; Step 5: Receive building permit; Step 6: Construct per approved plans; Step 7: Apply for construction completion certificate when finished

Consequences of Unlicensed Extensions

For property sale: Buyers needing mortgages may face problems as banks verify extension legality
For mortgage purposes: Some banks won't appraise unlicensed extensions, reducing available loan amounts
Penalties: If discovered, may be required to demolish or pay fines

Recommendation: When buying any second-hand Chiang Mai home with extensions, always verify that complete building permits exist for all extended sections before deciding.

MORE Value. MORE Trust. Always.
Contact us today for a free consultation:
Line: @morecm | www.morepropertycm.co.th
Aurakanya: +66 83-236-9428
Eknarin: +66 96-236-9745