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  • Writer's pictureZack Jurkowski

How to Prepare Your Floor for Tiles (Without Losing Your Mind)

As a licensed general contractor specializing in bathroom and kitchen renovations in Montreal, I've seen my fair share of DIY tile projects gone wrong. And while tiling can be a fun and rewarding project, it's important to start with a solid foundation - literally.

Assuming your subfloor has just been redone, here's what you need to know to prepare your floor for tiles without losing your mind.

Deflection Limits: Don't Let Your Tiles Crack Up

First things first: you need to make sure your floor is structurally sound. When it comes to tiling, this means making sure your floor meets deflection limits.

Deflection limits measure the amount of flex in your floor when you walk on it. If your floor deflects too much, your tiles will crack - and no one wants that.

Generally, deflection limits are measured in terms of L/360. This means that your floor should not deflect more than 1/360th of its span when you walk on it. If this sounds like gibberish to you, don't worry - your contractor will know what it means.

Leveling Your Floor: It's Not Rocket Science, But It's Close

Once you've ensured that your floor meets deflection limits, it's time to level it. And let me tell you, this is where things can get tricky.

Your floor needs to be level within a certain tolerance in order for your tiles to sit properly. This tolerance varies depending on the size of your tiles. Generally, the larger the tiles, the more level your floor needs to be.

I'm saying level because having your floor both level and flat is ideal. But in some cases, it can be slightly off level to avoid having a large step at the doorway. The important part is that it is very flat.

Uncoupling Membrane: What Is It?

An uncoupling membrane is a type of underlayment material used in tile installations to help prevent cracks and other types of damage that can occur when a tiled surface is subjected to stress, movement, or other types of force.

Essentially, an uncoupling membrane creates a separation layer between the tile and the subfloor or substrate, which allows for independent movement between the two surfaces. This means that if the subfloor expands, contracts, or moves for any reason, the tile will be able to move independently of the subfloor, which helps to prevent cracking and other types of damage.

Overall, the purpose of an uncoupling membrane is to provide a stable, long-lasting base for tiled surfaces, while also helping to prevent damage and protect against moisture. By creating a separation layer between the tile and the subfloor, an uncoupling membrane can help to ensure that your tile installation lasts for years to come, even in high-stress or high-moisture environments.

Schluter Ditra and DitraHeat are tile underlayments that can be used to uncouple your floor. The main difference between the two is that DitraHeat is designed to accept electric heating cables, which can be a game-changer if you're looking to add some warmth to your bathroom or kitchen.

Wrapping Up: Take Your Time, and Don't Be Afraid to Ask for Help

Preparing your floor for tiles can be a daunting task, but it doesn't have to be. Just remember to take your time, follow the manufacturer's instructions, and don't be afraid to ask for help if you need it.

At the end of the day, tiling is a skill that takes time to master. But with a little patience and a whole lot of elbow grease, you can create a beautiful, functional space that you'll be proud to call your own.

If this sounds like a foreign language, you might want to hire a licensed contractor to get involved with your project.


Montreal Contractors is a qualified company, holding an active bonded license as a General Contractor and Specialized Contractor with the Régie du Bâtiment du Québec (RBQ License: 5767-5480-01), ASP Health & Safety Certification and a $2M liability policy. Our employees have all passed background checks, are registered with CNESST and have their ASP Health and Safety certification.

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