Dry rot is the most serious, it can cause significant damage to buildings, it can spread and destroy large timber.
The wood can also crumble if touched and if exposed to light it can be yellow in colour.
Wet rot and dry rot are forms of fungal decay that can cause structural damage to builidings.
Wet rot is confined to the area of timber that is damp.
Wood may feel soft and spongy when touched and look black in colour.