The aging thoroughfare will be closed from Carlaw Avenue to Highway 427 from 8 p.m. Friday evening until 6 a.m. Sunday morning.
"A full closure of the expressway is needed to ensure safety for the public and for those working at the site," said the city in a news release.
It will reopen just in time for the Toronto marathon, which begins Sunday morning at 6 a.m. and goes until 3 p.m. on various streets throughout the city.
The city recommends drivers use Lake Shore Boulevard, the Queensway, Richmond, King or Queen street or Evans Avenue as alternative routes during the Gardiner closure.
The maintenance work, among other things, includes:
- pothole repairs.
- sign inspections.
- guardrail repair.