What does a quantity surveyor do on a self build?

An architect designs the house; a quantity surveyor looks after what it costs. On a self build that means: a budget built from measured reality rather than hope; builder quotes rebuilt onto one basis so they can actually be compared; the contract's money terms - payment, retention, what happens when things change - checked before you sign; each payment request valued against the work actually standing on site before you pay it; every change priced in writing before it is built; and the final account, the build's last bill, checked line by line at the end. Those jobs are separate fixed-fee services, so you can take the one that meets your worry, or have the whole money side run for you throughout under Commercial Management.