Three fire appliances from Shropshire were asked to help North Wales Fire Service deal with the incident at Northwood at 11.30pm on Wednesday.
Crews from Ellesmere and Whitchurch went over the border with an operations officer and an incident support unit.
A spokesman for Shropshire Fire & Rescue Service said they used a hosereel jet to deal with the blaze.
The Shropshire crews sent their incident stop message at 12.21am on Thursday.
North Wales Fire Service has been asked for comment.