Lime wash is mineral lime watered down so it can be easily applied to the surface with brushes. It gives the building a good waterproof covering and helps fill any imperfections in the lime plaster.
Lime wash is added to give the plaster added protection and is also designed to breathe along with the plaster. This allows the moisture to escape, leaving the timbers in perfect condition.
Lime wash is a better option than modern paint, which can often lead to moisture retention issues, plus has the advantage being the traditional finish expected of an old timber building giving it an authentic feel.
Some shy away from lime wash as it's not as durable as paint and will need to be re applied on a regular basis, possibly annually depending on the location of the building. It does however give your building a fresh crisp look and helps protect the building's future and avoid any nasty damp problems.