A suburban Pittsburgh man slept soundly as his home caught on fire and partially collapsed.

It wasn't until firefighters did a walk-through of the home more than two hours later that he woke up.

Ross Township Fire Marshal John Reubi says he was "flabbergasted" that anyone survived the blaze. It broke out around 2:40 a.m. Sunday and was reported by a passer-by.

Firefighters were initially unable to search for victims because part of the roof collapsed. After controlling the fire, firefighters walked through and found the man in a bedroom. Reubi says it appeared the man had no idea what was going on.

Officials say the house had several additions, perhaps shielding the man's room from flames. He was treated for smoke inhalation.