General Builder

Hi there, I've been living in the UK for the last 20 years but am planning to move the family over to Perth. My British husband is a builder who specialises in wet/dry stone walling, roofing, stove installation, driveways, and general building work. Although he is highly skilled I'm wondering what work might await him in Perth and what he might earn? He is 47 and also wondered if his age might be a factor? What Aus certificates might he need to work? Any advice would be much appreciated. Many thanks, Annaliese