This series of The Block might be the toughest ever (cold-water showers and all), but we're not leaving everything up to our couples.

Before they moved in, we were hard at work on The Block, ensuring that not only were the properties ready for renovation, but they were actually safe.

That meant dealing with asbestos, which is the hard reality of renovating houses as old as our Victorian terraces.

"Asbestos is an absolute killer and if you're thinking of renovating, make sure you get your place checked out by professionals," Scott Cam says. "If you do find something, make sure those professionals remove it."

On The Block, each house was thoroughly audited for hazardous materials by an independent hazardous material and monitoring contractor.

"The individual results varied from house to house, with each one having minor asbestos installations present, as is normal and expected for any older house," The Block's architect, Julian Brenchley says.

"Following the results of those audits, a process of identification, encapsulation, removal and disposal was undertaken by licensed hazardous material contractors."

Now that our 150-year-old Block has been given the big tick for safety, the stage is set for our four couples to create their masterpieces.