We have a house some km from Siwilai close to Phon Charoen.
We was building a garage on the sunny south side of the house, the garage is warm but the wall to the house is cold.
As Finnsk said, you and your wife must be there. If you have no time now, wait till you have time, it don´t take to long time to build a house.
Your wife must be there when it comes to buy material for the house.
If you´re not there it will be way much moore expensive.
When we were building our house, my wife and I bought all the material and the lokal builder build the house.
Our neighbour used a "construction company" way much more expensive.
They were cheated in many ways.
English is not my language, hope it´s readable.
And good luck, maybe we´ll meet one day at the lokal market in Siwilai.