Just curious, roughly how much to build a house in LOS? Last time my boss said she spent half a million to add one more storey - look like attic to me - to her semi d in SG.
Your boss add one more storey in Singapore, first of all Singapore construction cost is expensive. Secondly adding one more floor means connecting to existing structures and have to strengthen them too so the cost can be very costly.
I cannot tell you how much to build a house in Thailand because very much depend on the quality and material one choose and also the size and design. It difficult to tell you really.