Fire crews initially struggled to contain a fire at a house in mid-Canterbury this morning

The family managed to escape before four crews arrived at Chalmers Ave in Ashburton at about 6.30.

A FENZ spokesman says crews are mopping up the fire, which damaged the back half of the house.

He says they initially had difficulty gaining access, as old roofing iron was still under the new roof.

A fire investigator is on the way to the scene.