Investigators still can't say for certain what caused a fire Saturday night in a vacant triple-decker at 32 Edgewood St. in Roxbury.

The blaze, which engulfed porches on the rear side of the building, caused a total of $310,000 in damage, Boston Fire Department spokesman Steve MacDonald told Metro. The fire also damaged the exteriors of buildings on either side of the property, MacDonald said.

"The flames were so intense it melted the siding on the house to the right, and it did about $10,000 in damage to the house on the left," he said.

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Two firefighters were treated for minor injuries and have since been released, MacDonald said.

Part of the investigation includes whether anyone had been living in the home, which had been thought to be vacant, he said.

MacDonald couldn't say whether the fire was deemed suspicious.

He said it's unlikely the home will need to be demolished.