Hello, I recently replaced my rotted timber ground floor in our lounge with an insulated beam and pot solid construction. The original skirting boards were a casualty of this process. In looking to replace them I wanted to use softwood skirting boards pre-treated by preservative under pressure (Vac Vac or Tanalith). I was told by our contractor that this was not possible as only structural timbers can be treated in this way. Some of the skirting boards need to be fixed to a north facing wall that is prone to condensation, particularly during the winter months, so untreated timbers in this location would be vulnerable. Do any contributors know where wrought timbers can be treated with preservative by pressure impregnation? I live in the West Midlands. Many thanks.

Maybe try tracking down a local saw mill that have there own equipment for preserving timber, failing that could you not just treat it yourself ? 
Have you  considered addressing the cold wall to eliminate this problem ? Could it be insulated? 
Limited information on the bigger picture so hard to advise but addressing the cold areas would be my priority. 

The timber that comes out of a vacuum treatment contains the nasty chemicals and the oil that carries them, and is covered in it.. When fresh out they look and feel oily. Therefore I suspect that paint will not stick well.

Perhaps better just to paint the back with wood treatment. You could also put felt or similar between the skirting and the wall surface.

Assuming the room is heated and well ventilated you shouldn't have condensation issues.

 

Insulating the wall really should be considered to keep the surface above the due point.