There’s a reason why bathrooms on home renovation shows often deliver the most wow factor – a good reno can transform a damp, dated box into something beautiful and functional. That said, the process involves so many trades and know-how that it’s also one of the toughest renovations of all. “Bathrooms can serve up a lot of hidden costs,” says Paul Naylor, CEO of the NSW Master Plumbers Association. “As soon as you touch it, the unforeseen becomes an issue.”

Rebecca Senyard, Queensland-based plumber and blogger at ThePlumbette.com.au, agrees that problems easily pop up once tradies are on site. “Termites can be uncovered from a leaking shower pipe, or your house might not comply with current plumbing standards and needs fixing, so having a 20 per cent buffer in your budget is ideal,” she says.

Here, Rebecca and Paul give us their dos and don’ts when it comes to getting your bathroom renovation done right.

1. Do… hire a builder, not a plumber, to manage the project. Plumbers only run the pipework and install the fixtures, says Rebecca. “Engage a builder who can oversee the project from demolition to completion and organise the correct sequence of trades,” she says. “Project-managing the job yourself, if you have little to no experience, will be stressful, overwhelming and potentially costly if you make mistakes a builder would’ve known to avoid.”

2. Don’t… even think about DIY. Waterproofing, for example, should be done by someone licensed, warns Paul. “People spot waterproofing gear at their hardware store and do it themselves, but the costs for fixing a leak further down the line can be astronomical,” he says. Ditto for DIY plumbing, says Rebecca. “Doing it voids your house insurance – there are significant fines – and it can result in disaster if an appliance hasn’t been installed properly,” she says.

3. Do… buy products that comply with Australian standards. In other words, end your love affair with the imported Italian showerhead that plays Vivaldi while you’re beneath it. “All products installed in a bathroom need to be covered by an Australian Standards WaterMark,” says Paul. “If it doesn’t, the plumber isn’t legally allowed to install it.” Buying from specialist bathroom stores and choosing reputable brands will also mean less headaches down the track if you need a spare part.

4. Don’t… ignore antiquated pipework. Your eyes may glaze over when the plumber tells you to upgrade your pipes, but it’s crucial to do it – especially if you have ‘old gal’ water pipes in the floors and walls (used on houses in the 1960s), says Rebecca. “You’ll notice the water pressure is significantly reduced due to sediment formed in the pipes. I recommend replacing all water pipes and connections with copper or reputable plastic pipe.”

5. Do… avoid overcapitalising. It’s easy to go overboard, especially if you go to town on expensive taps, tiles and that heated toilet seat you’ve coveted ever since your trip to Japan. “If you plan to sell eventually, ask yourself, ‘Am I going to make this money back?’” says Paul. “Because what you’re doing is just making a decision for a new owner that may be to your taste but not theirs, which might be reflected in you not getting the price you want.”

6. Don’t… move pipework if you can help it. “Keeping the same layout for your bathroom means your plumber won’t need to touch the drainage pipes and that’s good news for your budget,” says Rebecca, “but be aware that water pipes will need to be reworked to suit new fixtures – like a mixer to replace taps, or a wall-hung vanity that’s replacing one on the floor.”

7. Do… consider the pros and cons of recessed cisterns. What’s not to love about a loo that hangs out of the wall, gives your bathroom a modern look and saves space? Well, the cost is a bit more, and you do need the space for the void behind it, warns Rebecca. “Let your builder and plumber know that you’re installing an in-duct cistern, as it has to be installed prior to the walls being sheeted and tiled,” she says. “The buttons are then installed after the tiling.”

8. Don’t… forget to nominate heights for things like benches and showers. If you don’t, the builder or plumber may abide by standard heights and it can be costly having to redo things, says Paul. “Discuss these issues at the start, because you might end up with your tradie saying, ‘Well, you didn’t raise it with me and it’s not in the contract so if I have to modify it, it’s your cost’,” he says.

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