Introduction

The substrate of a floor or wall includes the setting bed and any other layers beneath the tile surface. Even if tile adheres firmly to its setting bed, it won't last long if that setting bed isn't part of a completely sound and sturdy substrate.

The structural needs of your substrate may change when you add a new type of surface. For example, if you are planning to install ceramic tile on a floor that currently is covered with resilient sheet flooring, you will be adding a lot of weight to the underlying framing. If you doubt that the joists and subfloor are strong enough, consult a professional.