Why you should leave your bathroom waterproofing up to an expert


Waterproofing is literally the foundation of any bathroom and while it’s invisible if it’s done properly, the result of an amateur’s effort will be only too obvious. If the job’s not done right, you’re looking at rising damp, mould, rotting plasterboard or peeling paintwork. Worse, water leaking into the floors and walls could cause structural damage. It could mean having to rip everything out and start all over again.   


So before you even start thinking about those sexy new taps and stunning tiles, that luxurious bath or spacious shower, you need an expert in bathroom waterproofing to make sure your space is watertight.


What is it?

Waterproofing is like a rubber skin forming a protective film to make sure water doesn’t escape from your bathroom. It’s a super flexible polyurethane product that’s applied like paint and dries to create an impenetrable membrane. The whole process takes two to three days, then up to five days to cure depending on your climate. 


This isn’t a job for DIY.

We DIY to save money but if you don’t get this one absolutely right, it could cost you thousands trying to undo the damage caused by leaking water.


Bathroom waterproofing is a specialist skill requiring meticulous attention to detail. The waterproofing fails if the area isn’t cleaned and sealed first. The surface must be primed and prepared properly and then the liquid rubber waterproofing membrane is applied but the coating can’t be too thin or too thick. It needs to cure and dry properly before a second coat and if it’s damaged in any way, if there’s even one tiny hole, it will leak. Extra care is needed for corners and edges, and where walls and floor join, to create a smooth surface so there’s no break in the membrane. These danger areas for leaks are sealed with silicon then a special bandage is applied to create a flexible bond breaker which is also used around drains and taps.


This is one job you definitely want to leave to the experts. 


It’s not optional

Bathroom waterproofing is not a choice - it’s mandatory for every bathroom by law. Building regulations require the floor and walls of a shower to be waterproofed up to 1.8 metres. Bathroom walls need to be waterproofed to a height of 1.5 metres. You’ll also be waterproofing your bathroom floor if it’s made of timber or if your bathroom is upstairs. That’s the minimum. But it’s smart to waterproof every bathroom floor as well as the areas around your toilet, wash basins and the bath.


Some councils require an inspection of the bathroom waterproofing, even if it’s done by an expert.


How much does it cost?

Bank on $35 to $60 a square metre, $600-800 for a typical bathroom, more if it’s upstairs. It will be cheaper if you’re waterproofing other wet areas too, like an ensuite, laundry or kitchen. This is not a job you want to skimp on though. Choosing an expert will save you thousands in the long term.


How do I find an expert?

You’re looking for an experienced waterproofer who has insurance and referees you can contact. Ask how long it will take, what product they use, what warranty applies and how much it will cost.


Some states require a waterproofer’s licence. There are specialists but tilers and other tradies may also be qualified. Most have a Certificate III in Construction Waterproofing.


Don’t pay the price for cutting corners. Their work might not be something you can see, but an expert in bathroom waterproofing will mean you won’t discover any nasty surprises later on.