It has been 16 months since the worst hailstorm in a decade tore through central Queensland, yet hundreds of homeowners are still waiting for their roofs to be repaired.

The supercell caused an estimated $840 million in damage after catching Rockhampton locals by surprise on a Sunday afternoon in April 2020.

A shortage of materials and the volume of insurance claims have worsened delays, with warnings it could take another two years for all homes to be fully repaired.

Len Palmer said he was meant to have tradies start this week on his asbestos-ridden roof, of which 80 per cent was damaged. But he is still waiting.

"Some of the hailstones were the size of cricket balls and two waves come through. The big stuff came through and belted us with the big hail and the small stuff came through and the whole yard was blanketed in snow," Mr Palmer said.

"It's crazy, it's just mayhem."

Business challenges

Roofing company owner Clint Wehmeier said the hailstorm had been a "godsend" for his business, with 200 repair jobs still on his books and hundreds more around town.

The steep demand for services, however, came with its own challenges.

His focus has been on securing new building work to make the most of the housing boom, but he said it had been a struggle sourcing materials such as screws and timber.

"Insulation is another one. We're hearing reports they're even talking about importing insulation into Australia because we just can't get enough of it," Mr Wehmeier said.

Master Builders central Queensland manager Michelle Traill said some businesses had reported waiting weeks for materials for roofing and faced skyrocketing costs.

"There's a real supply issue in timber, which affects trusses for roofs. There's a boom in the United States where we used to get a lot of timber imported as well," she said.

Businesses flocking to capitalise

Tradespeople from across Australia have flocked to the region to cash in on repair jobs.

Ms Traill said there was still up to two years of roof repair work from the hailstorm in the pipeline.

"In the long run, we do need outside contractors to support our local contractors as well, otherwise people could be waiting an extended period of time."

Mr Wehmeier said he was still fielding calls about new insurance claims 18 months after the storm hit.

"Everybody has to have some patience. It's a very difficult, very trying time."

Insurance industry surprised

International organisation Swiss Re Institute measures insurance risk, and in its report from April this year, it said the Rockhampton hailstorm caught the industry off guard.

The final estimated industry loss was $839 million, and Swiss Re Institute said insurers were hit with higher than average claims.

The institute said factors such as solar panels, the older age of homes, and new requirements for cyclone building codes added to the cost.