The Ontario fire marshal's office is investigating a massive east Ottawa fire that destroyed one home and damaged two other homes.

Four people are now homeless from the blaze, which almost destroyed a neighbouring home.

Neighbours called 911 after seeing smoke and flames visible from the two-storey house at 21 Florette St, southeast of Blair Road and Montreal Road, just before 7 p.m.

Flames spread quickly from this home on Florette Street southeast of Blair and Montreal in Ottawa's east end. (Submitted by Caren Doherty)

A third alarm was raised after the fire spread from the home to the back patio of a neighbouring bungalow at 23 Florette St. A third home's siding was also damaged.

The fire at the second and third homes was quickly put under control, leaving fire crews to focus their attention on the Florette Street home, which had showed signs of possible collapse.

Homeowners on vacation

The home where the fire began is completely destroyed with $750,000 damage. The residents of the home, a couple, were on vacation and not home at the time.

They had been renovating the home for the last few years, according to neighbours, converting the bungalow into a two-storey dwelling.

The scene from Florette Street, where fire crews were battling a blaze that spread to two homes. (Michel Aspirot/CBC)

Two people at 23 Florette St. are also temporary displaced due to the fire, which caused $75,000 in damages to their home.

The third home suffered $25,000 in damage.

There were 15 fire trucks and 45 firefighters who responded to the call, which was originally to a neighbouring address on Elvina Street.

Police had closed Blair and Elvina roads for a time but the roads have since reopened.