Just before 1 PM Sunday Everett Fire crews were called to a mobile home park in the 7700 Block of Hardeson Road for reports of heavy smoke coming from one of the homes.
There were no people there at the time and firefighters had to force entry to gain access to the fire.
A dog was inside but was quickly accounted for.
Firefighters were able to contain the fire to the general area of origin and keep it from spreading to other rooms but the home suffered serious damage and the residents will need to make repairs before they can live in it again.
There were no injuries and an investigator with Everett Fire has been called to the scene to determine the cause.