The Waterloo and Valmeyer fire departments responded about 9:25 a.m. Thursday to a house fire at 3121 Trout Camp Road.
The house was unoccupied at the time of the blaze, with the exterior of the structure on fire upon firefighter arrival.
Waterloo Fire Chief Aaron Shive said a heat lamp in a doghouse located next to the home caused the fire, destroying the doghouse and damaging both fencing and an exterior corner of the two-story residence.
Waterloo firefighter Matt Blind, who lives nearby, was first on scene and knocked down much of the fire using a garden hose on the property, Shive said.
Three pit bulls at the home were unharmed in the incident.
“They were super friendly and came right to us,” Shive said.
The owner of the home is Ervin Fedro.