Julie MacDonald was recuperating from illness at her home in suburban Langford, outside Victoria, when a loud crash woke her from a nap.

"I heard a huge bang, and just woke up abruptly like really startled, really scared, knowing that they're developing beside us," MacDonald said.

When she looked outside she saw a huge boulder had struck the house.

An employee of Vimex Construction who was operating an excavator Monday at a construction site next door lost control of the boulder. He was sorting rocks to build a retaining wall for a new condo development.

The shoulder-high rock smashed the stucco and split the wood on the outer wall of MacDonald's rented house.

Julie MacDonald said the impact of the boulder split the drywall and knocked pictures off the wall of her eight-year-old daughter's bedroom. (Julie MacDonald)

It also split the drywall in her eight-year-old daughter's bedroom and knocked pictures off the walls.

"My daughter's room was just a mess," MacDonald said.

Seeing the damaged wall and objects displaced by the impact, she said, "I kind of got a little emotional, thinking 'What if she was in here?' "

Second escaped boulder

MacDonald says she is concerned because it's the second time the crew has lost control of a boulder at the site.

Retaining walls of stacked boulders are a common sight around new developments in hilly, fast-growing Langford.

MacDonald says her landlord and the construction company have been helpful so far.

"Makes me wonder why nothing's been put in place here, and how not one, but two rocks can get away on them," she said.

"Not even rocks — boulders. What's next? is it going to happen again?"

Julie MacDonald took this photo of the boulder that crashed into wall outside her daughter's bedroom. She said it is the second boulder that's escaped an adjacent construction site. (Julie MacDonald)

Rod Rogers, the site foreman for Vimex Construction, said the employee tried to stop the boulder from rolling into the house, but it's difficult to regain control of a rock with a machine.

Rogers said the crew will now sort rocks further away from the home.

With files from Liz McArthur.