The use of appropriate conservation and refurbishment techniques is critical to the preservation of buildings. This major Digest gives advice on how to apply safe, effective, appropriate and enduring conservation techniques to renders, plasters and stucco. It outlines how to identify plaster and render constituents and associated mortars, and how to diagnose the causes of deterioration. It advocates avoidance of cleaning to optimise the life of masonry but outlines its use where appropriate. The first part of the Digest (published in 2008) dealt with conservation of stonework, and the second part (published in 2009) covered brickwork, blockwork and terracotta. The companion Digest 502 explains the principles of the conservation of masonry in historic buildings.

Illustrations

4 line drawings, 18 photos

Pages

24pp

Contents

Terminology
History of the use of internal and external plaster
-Lime and cement-based materials
 Binder development
-Gypsum-based plasters used largely for internal finishes
Identifying and reporting plaster and render constituents, their specification and condition
-Determining and reporting of condition
Constitution, sources of raw materials, manufacturing, varieties and how plasters and renders work
-Gypsum plaster wall coatings and polymer-bound fillers
-Mortar-based wall coatings
Specification and application techniques for both new work and repairs
-Background preparation for all plaster systems
-Plastering techniques for all taditional plaster or render systems
High-technology application-specific finishes
Causes of deterioration
-Staining and discoloration of renders
  Smoke deposition
  Leaching of lime
  Water staining
  Biological growths
  Transition metal oxides
  Internal damp staining
  Internal pattern staining
Remedial work
-Cleaning techniques
-Deterioration, decay and repair of renders and plasters
  Map cracking
  Crazing
  Curling and peeling
  Acid rain erosion
  Sulfate attack
  Sulfation
  Frost damage
  Salt crystallisation
  Hollow areas, detachment and spalling
  Incorrect materials and techniques for patch repairs
  Paint finishes
  Deterioration of gypsum plasters due to persistent dampness
Conclusion
References and Further reading
Appendix A: European and other test standards for renders and plasters
Appendix B: Test methods for cube and adhesive strength of plasters, total mortar and plaster shrinkage, water vapour permeability