4 tips for the best bathroom renovation

If you’re planning a bathroom renovation, or you will be creating a new one as part of a home building project, take note. When it comes to bathrooms, there are many chances to mess up in ways that aren’t obvious until it’s too late.

Abundant moisture, lots of traffic and small floor areas mean a new bathroom renovation often ages poorly if you don’t have the correct hidden features in place. And by hidden features I mostly mean systems that waterproof things from behind the scenes.

Whatever you do, remember the four details you’ll find here. They make all the difference.


#1: Choose a good toilet

toilet label
Not all new toilets actually work well. Independent testing is how I found the Toto brand that works so well.

Toilets are one of the few consumer products where some brands and models come new from the factory unable to perform as they’re supposed to. The low-flow revolution is why.

Toilet manufacturers launched new water-saving models with insufficient testing, resulting in a surprising number of toilets that can’t flush properly. You can identify effective models before you buy at a free website:

I installed two bad toilets in my house when I built it in the late 1980s before this list came out. A few years later I changed them for two lab-tested Toto Drake models and they perform flawlessly in our household of seven people.


#2: Opt for a powerful fan

ceiling fan
This ceiling fan moves twice as much air as standard bathroom exhaust fans and this is a huge advantage. This fan is also remarkably quiet.

Shower moisture is highly destructive to paint (especially painted ceilings), spawns mould growth and damages window frames. That’s why you need a powerful exhaust fan in your bathroom. And by powerful, I mean something more energetic than is usually installed.

Standard bathroom exhaust fans typically move 80 to 90 cubic feet per minute but, in my experience, that’s not nearly enough. Aim for a fan that moves at least 120 cubic feet of air per minute, and one that does it quietly.

“Sones” are a unit of noise output used by the ventilation industry, and a 1.0 sone fan is very quiet indeed. This level is usually only achieved by the smallest fans. The best you can probably find in the larger models is 1.2 to 1.4 sones, but that’s still very quiet.

insulated duct bathroom renovation
When a bathroom exhaust installation travels through unheated areas on its way outdoors, be sure to use insulated ducting. It prevents condensation and frost build-up during winter.

It’s also vital that if the duct leading from your exhaust fan passes through any kind of unheated space the duct be factory insulated to prevent condensation of the outgoing air. If the warm, moist air is allowed to cool, it will form liquid water in the duct, typically running back down into the fan and into your bathroom. The duct below is an example of an insulated one.

#3: Waterproof before tiling

schulter kerdi bathroom renovation
This waterproof fabric is called KERDI, and it’s part of a waterproofing system made for use under ceramic tiles. This KERDI cone is holding water with nothing more than an overlapping seam — no glue and goop. You wouldn’t use KERDI like this normally, but it does show how effectively it holds water back.

Ceramic tiles might seem waterproof, but they’re not — at least not entire tile installations. Grout joints are the reason why. Even sealed grout is porous, and spilled, splashed and dripped water is a given in any bathroom. Even if you’re reasonably diligent, this water will soak through grout and into wooden floor and wall structures, causing unseen mildew, mould and rot. The trick is to create a waterproof membrane underneath the tiles that doesn’t interfere with the solid and durable attachment of those tiles.

Schluter is a tile accessory company that pioneered the most advanced moisture control products I’ve seen so far for tiled installations. Their KERDI product is a cloth-like material that goes down on walls and tub surrounds, protecting them from all water contact.


Schluter’s DITRA is a dimpled plastic membrane that goes down on floors, boosting the crack-resistance of tile installations while also waterproofing the surface underneath. You can see a version of DITRA below that’s made to accept in-floor heating cables.

bathroom renovation tile installation
This cross section shows the orange DITRA membrane that helps prevent tile cracking, the grey in-floor heating cables, thinset tile mortar and then, finally, tiles.


Tile installation

See a professional tiling installer in action, using an uncoupling membrane to boost reliability when tiles go down on plywood.


#4: Durable caulking

Caulking is a simple and secure way to anchor new countertops to a bathroom vanity and polyurethane caulking is substantially better than any other formulation I’ve used as an adhesive and for sealing. Polyurethane caulking used to be more common on store shelves than it is now, but I currently buy a brand called Sikaflex. You can order it online and it sure does work.

Bathroom durability usually comes down to a few key details applied where they count. And like most things in life, the details of a great bathroom renovation aren’t obvious and aren’t automatically done. Insist that they’re completed right and you’ll enjoy many extra years of trouble-free service from your new bathroom.


About the Author

Steve Maxwell

Steve Maxwell

Steve Maxwell has been helping Canadians with home improvement, gardening and hands-on living since 1988. Visit for videos, stories and inspiration.



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