The death of a 17-year-old boy at an Adelaide construction site was "utterly preventable", the construction union says.

The young worker was taken to hospital with critical head injuries and died after a timber frame fell on him when a wall collapsed at a residential building site in Fullarton.

CFMEU SA secretary Dave Kirner says there was an appalling lack of basic safety at the site.

“There was no site manager, no first aid facilities, no amenities and no safety officer. And no one was wearing hard hats,” Mr Kirner said in a statement.

“In the residential industry, you see people working at heights with no protection, you’ll see people working without hard hats, you see electrical leads and equipment laying on the ground.

“This is safety 101 – hard hats are a basic necessity to protect you from falling objects which are not uncommon on construction sites.”

Mr Kirner has called on housing groups to agree to proper regulations for residential construction sites and the government to enforce proper safety regulations.

Safework SA is investigating the incident and police are preparing a report for the coroner.