Over the last 3000 years it has been common practice in the construction of buildings to use materials that are abundant and locally sourced.
A large number of historical properties in Nottingham have been finished with a render coat, basically this consists of a lime and sand mixture which more often than not will contain some kinds if animal fiber e.
g.
horse hair, cow hair and possibly even pig hair.
These animal hair renders were mixed in the original composition to improve the overall strength of the plastering.
The animal fibers act in the same way as the glass fibers do to reinforce fiber glass in modern building materials.
An exterior render may have been applied by builders to cover degraded brick work, which due to ingress of water and actions of hard frost have caused so much damage to the bricks themselves that the only economic solution to tidy the appearance is to apply a render the whole exterior of the building.
Effectively giving the building a face lift and a new weather proof coating.
Traditional lime plaster has been used since the Romans first settled.
Lime plaster was used to cover the rough stone work on the interior walls of the building.
Also lime render was used to cover wooden laths, which are the earliest forms of stud walling.
When it comes to the restoration and repair of traditional lime mortar it is essential to examine the composition of the existing mortar, to ascertain exactly what it was that the original builders applied to the walls.
This will make it simple to match the existing plaster in both texture and color.
A general rule for applying horse hair based plasters, when the plastering trowel is struck against the mortar hawk and dragged along and lifted you should be able to count between 20-30 individual hair strands, protruding past the end of the trowel.
Lime renders take a long time to dry and should not be decorated until the drying process has completely ended.