The 3-alarm fire broke out at the home in the 5100 block of Laurelcrest Lane just after 3:30 p.m. A thick black column of smoke was visible across much of Seattle and the Lake Washington shores.
One construction worker suffered serious burns and was taken to Harborview Medical Center in Seattle, but his condition was not known. A Seattle firefighter had to be treated for heat exhaustion.
The raging blaze sent embers flying across the neighborhood and five nearby homes suffered fire damage as well, with the immediate neighbors' homes suffering significant damage, officials said.
Investigators said the fire started when paint fumes ignited after the furnace turned on.
Damage is estimated at over $7 million.