Are their any business that chemically treat and clean the mould, dirt and grim off the exterior of buildings etc?

I just bought a power washer and power washed mine. 
Dirt, mildew and grime came right off. 

Slapped a coat of paint on after it dried and it looks great. 

Would I trust some Thai workers to do this? 
Probably, as it was pretty easy. 

Although you can adjust the spray too strong and do damage if you hold it too close. 
Takes about 5 minutes to get it figured out. 

 

 

We bought a hyundai high pressure water cleaner from Home Pro its has twice the power of the black and decker

one we had previously and its much make with better quality components (no diecast parts)

Cost 13500 baht but well worth the money, cleans walls and floors very quickly  

Thanks for responding