1.    Plaster decorations on facades in lime-, gypsum- and cement-mortar

Introduction

As part of a European research-project on Plaster Architecture in Europe from the XIX and XX Century, the RAADVAD-Centre for Restoration and Traditional Crafts in Denmark has been studying Working Techniques and Repair Methods for Plaster Decorations on Facades.
The RAADVAD-CENTRE  is the national Danish research- and Information Centre for Restoration and Crafts. The Centre is specialized in the restoration of buildings with traditional crafts, traditional materials and traditional constructions. The activities of the Centre are: Research, information, education and training courses, consul-tants work and practical restoration work.
The Raadvad-Centre has 5 superior aims:
1 To promote the preservation of the Danish architectural heritage, including its character, its authenticity end its appropriate use.
2  To promote the maintenance of the building crafts, connected to the Danish architectural heritage, including a number of small firms where only a few craftsmen are executing their profession.
3  To promote the continuous production and use of a number of traditional materials and craft skills as they form part of old buildings.
4 To promote the most appropriate economical methods of maintenance and restoration of old buildings.
5 To promote and develop the manufacture and applications of the most sustainable materials, constructions and methods within the building sector. 

The research carried out for this project has implied analysis of written sources, gathering of practice experiences from concrete restoration works on plaster decorations on facades, technical experiments with materials and methods, tools and utensils.
The working descriptions aim to be a practical tool for concrete restoration- and renewal work on plaster architecture all over Europe.
The author, architect Soeren Vadstrup, Head of the Raadvad-Centre has been in charge of the research project, and has for this purpose worked closely together with crafts firms, restoration architects, other researchers and historians.

The material are also available at the digital Crafts- and Restoration Database belonging to the Raadvad-Centre on www.raadvad.dk - both in the English and Danish version. 

Typical elements of plaster decorations on facades

In the XIX and XX Century, it was very common to set up plaster decorations on building facades. The plaster decorations might look exactly like decorations in natural stones, but was much cheaper to produce. The primary purpose and effect of the plaster decorations is therefore to imitate and look like natural stone decorations. Drawing no. 1 shows some of these typical elements: Pediments, vases, balustrades, main cornices, friezes, casings, festons, ashlar and stucco decorations. 
Later on, from about 1870, the facades became more and more decorated and overelaborated, which lead to the original, innovative and vigorous Art Nouveau Style  about 1900 - 1916. Also the successors of this style, Art Deco and Functionalism imply facades with more limited plaster decorations. 

Typical mould elements

The plaster decorations very often have their ideal from antique Greek and Roman temples and architecture. Therefore they imply a number of typical mould elements from these models, elements which also are repeated in joinery, masonry, wood- and stone carving as well as interior stucco work.
The mould elements have both a simple and a more detailed shaping. The names for the elements on the antique Greek temples are often used for these common facade details. 

Working techniques

In the authentic plaster works on facades it is possible to distinguish between 5 various working techniques, which are further described in the next chapters.
1. Ornamented flat plaster on facades
2. Sunken batten decorations in plaster on facades
3. Running mould decorations in plaster on facades
4. In-situ modelled decorations in plaster on facades
5. Cast decorations in plaster, gypsum or cement on facades

These working methods have their own special elements and characteristics, but  in certain cases the various techniques may produce the same element, for instance a half column.

Index