Six fire crews from Lancaster, Garstang, Bolton-le-Sands, Preesall and Hornby, along with an aerial ladder platform from Morecambe put out the blaze in Bowland View, Glasson Dock.
The fire broke out around 4.30pm yesterday. A brigade spokesman in Lancaster said: "It started in one roof space and spread to the neighbours' roof next door.
"Both houses suffered severe damage."
No-one was injured in the blaze.