Brisbane couple Karlie and Will are taking on the challenge of a lifetime on the new season of The Block.

They’re taking on a renovation of epic proportions, as they restore the derelict headquarters of a historic soap and candle factory to its former glory, and turn their space into a three-bedroom, two-and-a-half bathroom luxury apartment, complete with an expansive outdoor terrace and city views.

It’s a big job — but surely Karlie and Will have plenty of experience with renovations, right?

“Literally next to nothing,” Will laughs. “We bought our first house just recently in Rochedale, and all we’ve done so far is paint three bedroom walls. That’s it. We got some paint and a paint brush and that’s it, that’s the extent of our experience with renovations.

“I have to say, though, that since we started on The Block, we’ve gotten a lot better at painting. We’re probably going to get home and look at the walls and say, ‘Oh my god, that’s terrible, let’s start again’.”

Will and Karlie may be a little on the young side (they’re both 25), but their relationship is sturdier than you might assume.

“We’ve been together for nine years now,” Will says. “We’re high school sweethearts. We were best friends in high school, and we went from there. We started dating, and I proposed on our seven-year anniversary.

“I’m the romantic type — I took her on a surprise trip to the Whitsundays. We stayed at the beautiful One & Only Resort on Hayman Island, and we went on a helicopter ride over the Whitsundays and Heart Reef and all the beautiful reef systems there. We landed on Whitehaven Island, and we had a private little picnic with champagne. And then I popped the question, and she said yes!”

Plenty of people have asked the couple how they expect their relationship to survive the pressure cooker of The Block — but they don’t seem worried.

“Karlie and I have a motto that no matter what, we always go to bed happy,” Will says.

“No matter what was said, no matter what arguments we might have during the day, by the end of the day we’re sweet and we go from there. That helps a lot. You know, we’ve been together for such a long time, and we’ve had a lot of ups and downs before this, so I think we’ll be fine.

“I can understand how it would break up some couples, because you are under a lot of pressure. There’s a lack of sleep, the time frame you’re trying to produce a room in is just ridiculous, it’s just a very stressful environment, and there’s nobody else to take that frustration and that exhaustion out on other than your partner. So I can understand why some couples do fight.

“But we said from the start, we’ll try our hardest not to do that. It was pretty much as simple as that. As long as we try our hardest and we do our best, that’s all we can do.”

While they’re not exactly seasoned renovators, Karlie and Will both have plenty of experience in the construction industry. She’s a quantity surveyor, and he’s an electrician.

“We love seeing a finished product,” Will says. “I wouldn’t say that’s a big advantage for us, necessarily, but it does help, knowing how things work. The Block is more about project management, though, than it is about working with tools or knowing a trade.”

If anything, Will says his experience in the construction industry can make life on The Block seem more daunting.

“As an electrician, and from working in the construction industry, I know time frames and what things can realistically be done in a certain amount of time,” he says.

“But trying to finish some of these rooms… outdoors, the kitchen, the hallway, whatever, just trying to get those done in a week, it just seems impossible. You look at your build on a Thursday, two or three or even four days out from the reveal, and you just think there’s no way you’re going to finish.

“But you pull through and you actually do get it done. It’s a bit of a shock when it comes to room reveals, knowing you’ve actually pulled it off in that time frame. But in order to do that, there’s not much sleep happening at all.”

The lack of sleep shows. When I talk to Will, I’m actually supposed to be talking to both members of the team — but Karlie is fast asleep, and Will is clearly exhausted. But they’re not about to give up now.

“We always stick up for each other, and we’re a team,” Will says. “There might be some older couples here, but I don’t think either of us would ever back down from them when it comes to confrontation. Our biggest strength is that we’re hardworking, we like to get our hands dirty, and we’re determined to do the best we can.

“If it’s not perfect, we hate it. We want to do the best job we can and win each week.”

The couple’s biggest strength might be their determination, but Will admits that their biggest weakness is their indecisiveness.

“When we’re at home we can barely decide what we want to have for dinner,” he laughs. “So when we started on The Block, we really had to jump outside our comfort zone and make some quick decisions. We just made those quick decisions straight away. It might only be a decision to choose a cushion colour or something, but in this game, when you’re dealing with the judges on The Block, you can win or lose based on that cushion colour.”

Ultimately, Will says, a win on The Block would mean the world to the couple.

“It’d be unreal for us to win this competition,” he says. “Karlie and I have done some amazing stuff before — we’ve travelled the world and we’ve grown up together, and we’re getting married next year — but this would be a huge tick.

“That’s why we applied for The Block — we felt like we were ready to tackle it head-on. We had nothing tying us down, so we could just go for it and give it our best shot. I’d love for the other contestants to do well, because they’re all fantastic, but we want to win.

“It’d be proof that we actually know what we’re doing!”

The Block will return for its 12th series on Sunday 21 August at 7pm on Channel Nine.