Flooring Centre Dunedin office manager Suzanne Chaplin said a large Envirowaste wheelie bin, nearly full of carpet and underlay, was set on fire about 4am on Sunday.
''It's pointless; I don't understand why they do it.''
The bin contents were highly flammable and the flames burnt higher than the Andersons Bay Rd building.
The bin was a ''melted heap'', an exterior wall was extensively damaged and the footpath badly damaged. The window of a store toilet was also broken by the heat. Thankfully, the fire had not spread and destroyed the store, she said.
The King's High School gymnasium and Gas And Water Ltd, in Glasgow St, were damaged by fire between 5am and 7am on Saturday.
Senior Sergeant Bruce Ross said police took a ''dim view'' of the three arsons. Inquiries were continuing.
Rector Dan Reddiex said yesterday King's staff and pupils were ''incredibly disappointed'' by the arson attack, which was just minutes away from destroying the school gymnasium.
''It was not a phone call you enjoy at 7am on a Saturday morning.''
An early assessment put the damage at $15,000 to $20,000.
''We're incredibly disappointed because the boys take a lot of pride in their school. It hasn't affected our use of the gym, but it's the fiscal impact that hurts. It's money that we'll have to redirect from the boys and their learning.
''While we're insured, we'll still have an excess to cover and it will affect our insurance premiums,'' Mr Reddiex said.
''The firemen reckoned it was only 10 minutes away from getting inside the building and causing massive damage. Thankfully, the alarms went off. We're so grateful to the Fire Service boys.''
Three bundles containing about 80 Otago Daily Times newspapers were used to start the two fires.
ODT distribution manager Kevin McGregor said yesterday ''an unusually large number'' of ODT subscribers in Bay View Rd, Macandrew Rd and Melbourne St reported they had not received their Saturday edition.
Dunedin police would like to hear from anybody who noticed newspapers being uplifted or suspicious activity in the King Edward St, Bay View Rd, Macandrew Rd area between 5am and 7am on Saturday, Detective Sergeant Brett Roberts said yesterday.
In late July, an arsonist melted eight wheelie bins in the Mornington-City Rise area and evaded an extensive police patrol.
Anyone with information should contact Dunedin police on 471-4800, or Crimestoppers on 0800 555-111.
