Can You Tile Over Joists? Here’s What You Must Know


When it comes to finding the best way to put a floor in your home or replace the floor, tile is a good option. But tiling can be a delicate material that needs proper care and it can be difficult to know the best way to tile onto the floor of your home.

You cannot tile over joists directly when putting tile into your home. Joists act as support for the floor of a home, but because they are made of wood should not be tiled over. The tile needs a greater surface for adhesion to be successful. The best thing to tile onto is rendering.

This article will look into why you cannot tile over joists, and will further explore other surfaces that are good to tile over when adding a nice tile floor to your home.

What Are Joists?

This main question of tiling over joists stems from a lack of understanding as to what a joist is. It is important to recognize exactly what a joist is and how it pertains to the topic at hand.

Joists are the supporting wooden structures that carry the weight of a floor. They act as dispersing points for that weight, allowing distribution of that weight to be put into the more solid beams. Then furthermore putting the weight into the supporting columns and walls of the building you are putting a floor into.

This makes it difficult to tile directly onto joists as they aren’t the actual floor itself, but pieces of wood that give support. Usually, plywood is placed over joists and beams to create a floor that can actually be walked on. From there the option of tiling becomes more plausible but could still prove problematic.

The reason being that tiling over wood can create damage to both the wood as well as the tiles themselves. Wood expands and stretches with a change in temperature and weather and this can cause tile to break as it is not as flexible as the wood. Furthermore, applying a wet adhesive to the plywood may cause damage, in the long run, can result in rotting of the wood.

Cement Backer Board

It is a good thing that with the progression of humans and our society we have many technological advancements that create a solution to such things as tiling over plywood. That tile still needs to be laid, but it can’t be applied to the plywood itself.

The cement backer board is a sub-surface for flooring. It is applied over plywood which is laid over the joists. This cement backer board acts as an in-between, giving the wood the ability to still move while keeping the tile in place and allowing it to stay firm without any cracking.

The cement backer board is easy to install and will usually have instructions to make installation even easier. Cutting it to the right dimensions may be the most difficult part of the process. That and the extra labor that it takes to put the board in. But it will keep your tile safe from damage and allow your floor to be secure and safe while looking good.

The Best Surface To Tile On

Even though a cement backer board is a great solution to tiling over that plywood that would cause problems for your tile, there is an even better surface to tile onto. It is called render.

Render is a surface that is a cement and sand mix and is applied to durable yet rugged materials such as brick to smooth out a surface. This mix is much like plaster as it is applied in similar manners, but is meant more for exterior projects.

The one catch for render is that it shouldn’t be applied to wood as that will cause problems to your floor. So the cement backer board is a better option for flooring itself, but it can be good to know about rendering for further projects dealing with tile. If you can render rather than use a different material then use render.

How To Tile: A Brief Guide

Because tiles can be delicate and fragile, it is good to know how to tile before diving into the project. The tile needs to be treated carefully so this will help those who have never tiled know where to start and how to begin.

First, you are going to need to clean the surface you are tiling. If this is a fresh cement backer board then most likely it is already pretty clean. But this is important as the tile needs to sit flat and if it isn’t then it will crack and break.

Then you will need to mix your tile adhesive. The adhesive should be a thick soupy consistency, almost like clay, so that it can be applied, but not make a mess. There will be instructions on tile adhesive products to properly mix this. The adhesive needs to be the correct consistency for it to work properly for the tile.

Start to cover a small area that you want to tile and use a notched trowel to spread the adhesive. Once again, only cover a small area as the adhesive will dry quickly. This gives you time to place the tile properly and let it set. If the tile is placed on adhesive that is already drying then it will not set properly and the project will be ruined. It is also a good idea to use tile spacers to create an even space between each tile. These spacers can easily be removed afterward and will let your tile look professionally done.

Once all of the tiles are in place it is time to grout the tile. This means filling in the small spaces between each tile piece. The spacers can be taken out at the point and the grout mixture can be mixed. Grout is basically just a softer mix of sand and cement that will hold the project together better. The grout can be placed over the tile and then using a large sponge that is damp and clean, spread the grout into the spaces, creating an even look to the tile finish.

Once clean-up is done and the tile has officially set you will have a clean-looking tile look added to your home that will make you feel proud of what you did. The tile is not too difficult to put into a home and can look really nice when complete.

Ricky Kesler

With all of the projects I've done over the years, you'd think that I work on my house full-time. But I actually enjoy other things like spending time outdoors and time with my family.

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