An HSE spokesman said its inquiry would centre on whether the man walked in front of a wall during its demolition or whether he was still working on pre-weakening when the wall collapsed.
This death follows a sharp rise in construction deaths recorded by the HSE last month. Deaths on site rose 59% to 62 between April 1999 and September 2000.
The figures led to urgent talks between the government and construction bodies on ways to reduce fatal accidents.