If you want to build on Koh Samui, you have to comply with some restrictions on the structure that you can build depending on the distance of your property from the beach.
Area 1 – If land is located up to 10 meters from the beach, no construction is permitted.
Area 2 – If land is located up to 50 meters from the beach, you can only construct a single storey building with a maximum height of 6 meters (including the roof). And each building cannot exceed an area of 75 square meters.
Area 3 – If land is located up to 200 meters from the beach, the maximum height allowed for any building is 12 meters (including the roof). Also, each building cannot exceed an area of 2,000 square meters.
Area 4 – If land is located more than 200 meters from the beach, the maximum height allowed for any building is 12 meters.
All properties must have peaked roofs; flat roofs are not permitted.
Less than 80 meters above sea level
No extra rules apply here with the exception of hotels (50 percent of hotel land area must be left unbuilt on and ‘green’) and residential projects consisting of 10+ units (must have water and waste treatment facilities).
Between 80 and 140 meters above sea level
A single family home can be constructed on land that is minimum 100 square wah or greater. Structures cannot exceed 6 meters in height and must leave 50 percent of the land unbuilt on and ‘green’. The architectural design should be based on traditional Thai, tropical or local aesthetics; must have a roof consisting of 80 percent of the total building area that matches the natural surroundings; and must have a water drainage system, to prevent flooding.
Higher than 140 meters above sea level
Same rules as above, but the structures cannot exceed 90 square meters.
If the land gradient is 35-50 degrees, a 6 meter high, single family home can be constructed. 75% of the land cannot be built on and 50% must have trees and greenery. If the gradient is more than 50 degrees – no construction is prohibited.