How Not to Use Mud Mortar in Ceramic Tile Floor Installation
Floor Tiles Installed
Beneath the beauty of a finished ceramic floor is a layer of mud. The mud evens out imperfections in the subfloor -- be it concrete or wood -- and it adds additional strength to the integrity of a wood subfloor, which expands, contracts and sometimes gives to weight and weather. The proper use of mud makes a smooth, level base for the additional of a ceramic tile floor to a room, but improper uses of this material can lead to disasters waiting to happen.
Required Tools and Materials
Bucket of water
Do not mix the mud with ingredients not recommended on the package. The manufacturer's instructions ensures that the product works at peak performance for the flooring job. If the manufacturer produces an additive, do not use water as its substitute -- perhaps the additive has strong bonding agents within its formula that renders the mud layer extremely resistant to cracking.
Do not self-measure the ingredients of the mud. Too much additive or liquid makes the mud product too thin to be a supportive foundation for the floor, while too little additive or liquid makes the mud too thick and clumpy to spread over the floor. Too little liquid may also prevent the necessary reactions that make the mud product into a solid flooring base from taking place. Always follow the manufacturer's recommended ratios of dry to liquid product in each batch.
Do not use mixed mud right away. Always allow the mud mix time to sit, for as long as the instructions recommends, to activate its bonding components that makes it the solid mud base for the floor. Sitting also allows air bubbles time to surface that would otherwise remain trapped in the mud mortar.
Do not use the mud mortar in uneven patches. The purpose of the mud is to make a subfloor sturdy and level enough for a tile installation. Every area -- from a small patch to the entire floor's surface -- must be smooth and level. If the mud is unleveled, so too will be the finished floor.
Do not use the mud as the thin-set mortar. While the mud is a mortar in itself, it is a mortar designed to bond to the subfloor and not directly to tile. A mud-mortared floor is not limited to a tile-floor installation -- it can form the foundation to other types of flooring solutions, including rubber and metal. Every floor requires a level base.
Apply a layer of thin-set mortar over the floor with a trowel, after the mud mortar sets and dries. Then comb through the thin-set mortar with the toothed side of the trowel, and then level and set each tile into its place on the floor.
Do not use the mud as grout. Grout is specifically formulated to bind tiles to tiles. The mud may not have as much added adhesive to its product as grout would, and unless the tile's tones are dark and earthen in color, mud may not go.
Mix the grout according to its instructions. Apply grout to the tile's grout lines with a rubber float and wipe away the excess with a damp sponge.
A Tip for the Job
Add wire mesh to the mud mortar for floors requiring a thick layer of mud, several inches thick. The mesh reinforces the floor and prevents large cracks from forming under pressure.
Resources and References
- HOMETIME HOW TO, Ceramic Tile - Floor Underlayment
Hometime explains the different underlayments used with ceramic tile including concrete backerboard (aka WonderBoard and Durock) and fiber cement (aka Hardieboard).
- Ceramic Floor Tile Installation
AsktheBuilder.com: Ceramic floor tile is not all the same. Many ceramic tiles have different hardness and wear characteristics. It is best to pick the right tile before you start installing ceramic tile.
- Mud work, A Dying Art - Archives - Floor Covering Installer