The Ontario Fire Marshal and Windsor Police are now investigating a pair of intentionally set fires over the weekend.
The first happened Friday night around 10:30 on Janette Avenue between Park Street West and Wyandotte Street West.
Chief Fire Prevention Officer John Lee says no one was hurt but damage totals $375,000, which includes a neighbouring house.
The second happened early Saturday morning around 3:30 on Midfield Crescent in Forest Glade.
Working smoke alarms are credited with waking up residents.
Lee says the fire started at a shed and spread to the house, three fences and a deck.
Damage is pegged at a half-a-million dollars.
Anyone with information on either fire is asked to contact police or Crime Stoppers.
- with files from AM800's Zander Broeckel