The fire were reported shortly before 2 a.m. on the second floor and then the basement of a house, which had been used for offices of a construction company. on East Ridgewood Avenue just off northbound Route 17.
Flames spread to the cockloft and a floor collapsed as firefighters hit the blaze above and below, responders said.
They had the fire knocked down in under an hour.
No serious injuries were immediately reported.
Firefighters from Maywood, Oradell, Rochelle Park and Saddle Brook were among the mutual aid responders.
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ALSO SEE: Several area companies responded overnight Thursday to a machine fire at a Rockleigh factory near the Rockland border.
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