Mr Sherriff was one of four firefighters attempting to extinguish a house fire at Deloraine, when the carport roof they were standing on collapsed. 

Taking the full force of the fall, Mr Sherriff was rushed to Launceston General Hospital where tests revealed he had damaged the ligaments in his left knee. 

Now on crutches and unable to work, the volunteer firefighter of 24 years said he considered himself "extremely lucky". 

"It all happened very quickly," he said. 

"We had been up on the roof for about half an hour before it gave way.

"I heard a crack and that was it. The crack was just a warning to hold on, because there was really nothing we could do."

The Deloraine and Westbury fire brigades were called to the Parsonage Street house fire about 9.45pm Sunday. 

With the fire spreading to the roof of the house, Mr Sherriff said it was a matter of finding a suitable vantage point to put the blaze out. 

"I put the ladder up through the man hole and could just see this red glow. We knew the fire was up, inside the roof," he said.

"The roof itself was really steep, so we couldn't get on it. There was an adjoining carport that was flat. 

"It was a perfect scenario to have it there, to get access to the fire. If we hadn't been up there, I don't think we would have saved the house."

A second firefighter also received minor injuries as a result of the fall. 

Reflecting on the incident, Mr Sherriff said he always understood the risks that came with the job.  

"It is very important to understand the potential for bad things to happen, but there is calculated risk for doing anything I suppose," he said. 

"At the end of the day I don't think I would do anything differently, if I had my chance again. We were able to save the house, that's what's important."

The fire has been deemed accidental.