Steam is generally safe to use on most surfaces but there are some exceptions to this. As you’re using water, using a steam cleaner on an unsealed surface isn’t recommended. And, surfaces that may react badly to a lot of water, such as solid wood flooring, may not be suitable, as you could get swelling. The situation is worse if you apply steam directly to the surface but also applies with steam mops. Although mop heads will absorb most of the heat of the steam, they can still get very wet, which is no good for many surfaces. For dealing with hard floors, we recommend that you buy one of our best hard floor cleaners, instead.