It is an age-old renovation dilemma: how to give a period home a modern makeover without losing its heritage appeal.

This is the major challenge facing the contestants on the new season of The Block, set in Melbourne’s bayside suburb of Elsternwick.

The renovation series has returned to houses this year, a welcome change from apartments for the show’s host Scott Cam.

“For the last five years we’ve had to go up eight flights of stairs because we don’t have a lift,” he said. “So that was a nice change to be on ground level.”

Five tired, old houses from around Victoria were saved from the wrecking ball and transported to a huge vacant site purchased by Channel Nine for an eye-watering $10.3 million.

The contestants not only have to completely renovate a dilapidated weatherboard cottage, but incorporate a two-storey extension at the rear of the house.

The five couples were encouraged to retain the heritage facade of each house, but strike a balance between historical and contemporary elements.

“It was a transition from old to new and that was a challenge for them … to get it flowing without too much of a jarring point,” Cam said.

Judge Neale Whitaker said he would be looking at the relationship between the heritage part of the house and the contemporary extension.

“I think it’s nice to have some kind of continuity; some kind of thread between the two very distinct parts of the house,” he said.

Asked whether any of the couples had surprised him, Cam said an inexperienced pair had proven to be the competition’s dark horses.

“We have some reno rookies who have never renovated before, and I thought were going to be in all sorts,” he said. “They actually did it tough at the beginning and then they improved along the way and ended up delivering a really fantastic house.”

Cam said all of the couples delivered a nice home. “But some did it the hard way, and some did it the easy way and some did it the very hard way.”

“In the end, they got there. But there’s a massive twist in the middle of the series that will shock a lot of people.”

Host of the popular reno series since 2010, Cam said he still gets nervous come auction time.

“It’s the only day I ever get nervous on The Block, I wake up with the jitters,” he said.

“We’re the only show in Australia that has no control over our grand finale.”

The Block premieres this Sunday at 7pm on Channel Nine.