The explosion happened in the 4400 block of Pearson Ave. at about 12:50 p.m.
"My whole house shook, and I just heard 'boom,'" said Angela Gallagher, who lives across the street from the home that exploded.
No one was hurt, much to the surprise of neighbors.
Roy Patel told Action News he had just sold the house at 4417 on September 30. He made an agreement with his son that he could live in the house until the end of October, before the new owners moved in.
Patel said his son was upstairs packing to leave when the explosion happened.
"He had to be taken to the hospital because it was a big, big sound," said Patel.
He said his son had to be checked out at the hospital, but he's okay.
"He's the luckiest guy ever," said Patel.
Chopper 6 flew over the scene and showed the roof was collapsed and a wall was blown out.
The fire was out by 1:40 p.m.
Investigators think the explosion may have been caused by gas, though it's too early to say for certain.
Gas service was turned off on the block, however it has since been restored, according to Philadelphia Gas Works.
Investigators said they will be looking into whether construction played a role in the explosion and whether the construction was done under a valid permit.
A spokesperson for Philadelphia License and Inspection said 4417 Pearson Avenue has been declared imminently dangerous. The owner has 10 days to figure out what to do with the building, otherwise L&I will demolish it.
In an effort to help stabilize the building, the roof and top floor were removed.
4415 is inhabitable, according to L&I.