Damp (or dampness) in a material usually refers to its content of free moisture (i.e. non-chemically bound), often to the state of a material when it is in a condition between being dry and being wet. Damp is an often misunderstood term. It tends to have a rather negative connotation, i.e. that if a material is damp there is an element of risk of material degradation or threat to health, whereas in reality all porous materials subject to the UK climate will contain some moisture from the air. Each porous building material used in house construction generally functions satisfactorily within its own particular safe range of moisture content, dependent on the location of the material in the construction and the function it is required to carry out. In construction, dampness is unwanted moisture or moisture that should not be there.