Travelled from Nong Khai to Phetchabun through Loei and passed an area that builds houses using recycled timber. There were quite a few areas with stored timber and partly built houses.
Not sure of the exact area but we travelled from Nong Khai on Drive from Route 211, นค.3041, Route 2020, Route 2098.
Probably a bit far from Pai, but might be worth a drive