Hello,

this might be totally stupid question to some of you but it literally raised a discussion with some friends recently.

If a piece of land is located on a quite steep slope, how is the size of the land measured? Is it measured from above i.e. with GPS coordinates or are there also areas (like small islands) where it is measured by literally walking up and down the hill and check the distance between some coconut trees for example?

Last option would result in a much smaller area to build on than a flat property.

For instance, 1 Rai on a 45° slope would only offer a bit less than 3/4 Rai actual building area.

Hope you can understand my way of thinking and someone knows the answer.

Thanks!!!

I would not buy and build on land with slope greater than 20^o as the cost of soil stabilization to prevent soil failure or slide will be too great.

The land should be measured flat by resolving the slope into its horizontal plane, else you will be paying out a lot for acquiring the face of a vertical cliff...

It's measured like it's flat, looking down on it from space. But the danger is not overpaying, so much. The BIG danger is when you build your house, the guy on the other side of your high property line sells his "dirt" with the help of a giant excavator and 10 big dumptrucks in a steady stream for days and thousands of loads of dirt hauling. You will end up with a 90 degree VERTICAL CLIFF, carved straight down from your wall or fence that could be 30' high or more. They won't leave an inch. There will be scratches on the fence posts from the tines on the excavator going straight down for 30'. In a couple years or less, depending on rain and soil composition, your wall or fence is gone down the cliff with erosion, and depending on how close your house was to the property line, your house will start developing cracks as the 90 degree cliff slowly erodes and eats into your land to a more natural 45 degree-ish state. Yes, you can always have a lovely time trying to sort out who owned it, and try to sue them. How well is that going to work out would you imagine? How long would that take? Who would win? How much money would you gain or have to spend? Also, the local road will be ruined with potholes from the endless overloaded dump truck loads traveling on it. If you want land with a view or on a slope, you have to buy the whole hill so that you own down to the flat all around from the high building site, or be the last house built with other houses already surrounding your property. And don't carve out a flat spot for a house. Just bring your piers above ground level up to the high elevation of the floor. Stilts. More expensive, but it doesn't look like "house-in-a hole". I live in the far north and don't know your location, but I reccon Bangkok doesn't have any hills. If I'm lie'n, I'm die'n. (As the Wolfman used to say!)

seems to me that there is a law that you can't build on land with more than 30* slope

could be wrong,read it some were

any how who would want to live on a slope ? one leg would be shorter thah the other from walking on the slope all the time

land is measured on the flat horizontal plane [GPS]

so 1 rai on a 45 slope is not 1 rai at all

otherwise we would all be building mountains on our flat land and making lots of money for the extra area

GPS is the best answer. It's really easy to do yourself with a friend.

a) Record a geometric plot with your Smart phone GPS by taking GPS data

from each corner of the plot.

Draw the plot on a bit of graph paper.

c) Now calculate square area of plot and add dimensions.

d) Draw a rectangle of the 'sloping plot' by measuring the actual area of the sloping plot with a surveyors tape.

OR

d1) measure the slope angle(s) with a theodolite

e) These simple steps give all the data you need to get an accurate land office valuation and a quote for stabilising the plot.IMO

HAve you noticed how there are no real chanotes on land in Thailand over 30' slope. The Gov owns it all. There are several levels, 4 infact of so called chanotes which give you the right to use the land but you dont reall own it. Only the top 2 have rights.