But miracles can happen – and no one was more surprised than Christopher, 61, who tells New Idea he was thrilled with the outcome, which has seen a fictional house become a real life home.
‘I just thought it couldn’t be done,’ Christopher says. ‘We had to retain the outside of the house, but if you’re going to do the inside, you have to do the stairway. I thought there was no way you could reconcile the two.
‘I was the Doubting Thomas, but I was happy to be proven wrong.
‘Ultimately you’ll see how they overcome the problem. It’s just amazing.’
The show has been a huge ratings success in the US, and has warmed the hearts of millions of Brady fans. Most reunions since the original sitcom went off air have been plagued with no-shows; Eve wisely stayed away from The Brady Bunch Variety Hour, and Maureen declined the ill-fated adult drama series, The Bradys.
But this new show was so fun, the original cast were all on board immediately. This surprised some fans, who feared recent reported tensions between Eve and Maureen might prove a problem.
According to Susan Olsen, who played Cindy, Eve ‘got tired of Maureen gaining attention for herself by regurgitating the tiresome and false insinuations that they had a lesbian affair.’ That was back in 2009, and it is believed the two women had not caught up since.
Christopher tells New Idea that while he perceived some mild awkwardness to begin with when the pair first got back together on the North Hollywood building site, that was quickly forgotten.
‘I think there might have been a little tension going in, because they hadn’t spent much time in each other’s company,’ he tells us.
‘Perhaps it was time to get back together, perhaps it was because this project was such a loving project, but that tension was soon dissipated.
‘And they got along well. There’s a certain unity and strength in being a group for all of us, that doesn’t allow any one-on-one tension to hold sway. It overwhelms that.
‘There’s no room for pettiness when you’re a Brady. It’s all about sharing, and there might be a lesson in that.’
Indeed, when questioned about talk of tensions recently, Eve seemed to indicate that it was all water under the bridge.
‘You know, we’re all grown-up now, obviously, and we all get along like real people. And HGTV just offered us an extended family reunion.
‘Just like any family reunion, having different memories of different events.’
Chris says that it was a real thrill to have the whole family back together, feeling that old Brady magic. And he says that’s due to a very real family atmosphere.
‘All six working together was a tremendous kick in the pants, there is a chemistry that exists between us, perhaps because we were raised together.
‘We spent those years, aged 10-to-16 around each other, and we’ve become family as a consequence, and you’ll see that in the show.
‘Other than my own family, there is nobody that I’ve maintained friendships with for as long as I have with Barry, Maureen, Mike, Susan and Eve.
‘They are my oldest friends, and I’m happy to call them friends. And I’m glad that it shows on screen, the love that we have - and the regard we have for each other.’
Christopher has some fun tasks in the Brady renovation, including resurrecting the iconic horse statue that once adorned the living room.
With the original piece missing, and the new version made for the Brady Bunch feature films apparently severely damaged in an earthquake, the actor was tasked with rebuilding it using cutting edge 3D technology.
‘The horse is the tenth cast member, the 11th if you want to count Oliver,’ he quips.
‘There’s not an episode where you don’t see the living room. And you can’t do this renovation truly without him.’
The kitchen, famous for its 70s orange and avocado green, was another fun project, and one that Christopher and Eve worked on together. So, when it was done, did he cook up some pork chops and apple sauce?
‘Of course I thought I should work on the kitchen because of all the rooms I’m attached to, there’s the pork chops thing,’ he laughs.
‘I needed to do the kitchen. I’m also a cook, I love kitchens, and I always thought the Brady kitchen needed improvement.
‘I didn’t realise that the whole idea was not to improve the kitchen, but to perfectly recreate the Brady kitchen!
‘I was flabbergasted to know that you could still get orange laminate!’
Amid all the amazing period detail that the Brady house now boasts, there’s one new feature that is definitely not in line with what we saw on TV – the kids’ bathroom now features a toilet.
‘The standards and practices department of the network ruled that you couldn’t show a toilet before 9PM,’ Christopher explains.
‘But this is a real house that has to have an occupancy permit, so ultimately it is built with a toilet.’
Other than the loo, the finished house is now so stunningly authentic that Christopher says it brought back some highly emotional memories – especially those involving TV parents Florence Henderson and Robert Reed, and Ann B Davis, who played housekeeper Alice – all of whom are no longer with us.
‘You can’t help but remember when you’re in a space that’s recreated to be an absolute duplicate of what we knew,’ he tells New Idea.
‘And that space was never experienced without Bob, Florence and Ann, and so there was sort of a feeling that they were there, because that’s the door that Robert would come through and say, “Hi honey I’m home”, and that’s the counter that Ann would work at, playing Alice.’
While A Very Brady Renovation is great TV, it’s also something deeper, says Chris – as fans relive something very special.
‘In a way the project is a tribute to Bob, Florence and Anne, and they are sorely missed,’ he says.
‘They would have had a gas working on this thing, and it’s too bad they weren’t physically around to enjoy it, but I have a feeling we might have had some guidance from afar.’
A Very Brady Renovation airs Mondays from 7 October at 8.30pm AEDT on TLC