Wellington's Marion Street is closed for the day while exterior earthquake-strengthening work is done on a seven-storey building.
Four huge steel frames are being attached to the outside of Rostrevor House building.
Each frame measures 23m x 8m and weighs 9 tonnes.
Rostrevor House body corporate chair, Chrissy Hill, says it's the owners who are paying for the work on the earthquake-prone building.
She wouldn't be drawn on the cost other than to say the price tag is less than $5m.
The building is 70 percent residential and was yellow-stickered in 2011. The owners had until 2026 to carry out the strengthening work.
Structural engineer Miles Seddon says it's unusual to simply attach frames like this to the outside of a building.
"But it's the most economical way to do it because you're not opening up things you can't see, and you can price the job from the outside."
The steel frames were pre-fabricated by Fitzroy Engineering in New Plymouth then driven to Wellington which kept the cost down.
"No one wants to buy earthquake-prone property so they had no choice but to strengthen", said Mr Seddon.
Rostrevor House was built in 1963 as a printing works.
The strengthening will bring the building up to 80 percent of the current building code.