Building conservation masterclass

Conservation and Repair of Plasters and Renders with David Odgers

Ref: B3D09128

Contact us

Places available

About this course

This course will provide an understanding of, and basic skills in, the conservation and replication of traditional internal and external plaster.

Rendered and plastered masonry and timber-framed buildings with rendered infill panels form a very important part of our historic and traditional building stock. Repair and maintenance can be a major problem and remedial work and specification are often of poor quality. This unique course covers history, documentation, condition survey, repair options, specifications, execution and quality control of remedial works to lime, gypsum and cement-based internal and external wall plasters and renders, from roughcast to stucco, including plain, moulded, modelled and cast work, with practical workshop exercises.

Course Description

Day 1

Introductions and a short presentation showing some examples of plasters and renders and the principles that underpin their use and repair

Day 2

Introduction to plasters and renders: an overview of the wide range of materials and methods of application used for rendering and plastering in the past, from earthen plaster to early cement stucco

History of plastering

Identification and description of mouldings and enrichments: examples of mouldings and demonstration of how the mould is made and used

Applying base coat plaster to moulding

Preparation of lath panel; applying first coat of plaster to lath; setting up and running the mould in situ

Deterioration of external renderings and walls and ceiling plasters, symptoms and cause

Day 3

Introduction to and preparation of non-hydraulic lime plasters including hot lime; use of hair and synthetic fibres. Mixing different mixes incorporating different binders, additives, etc.

Setting up and running the mould (finish coat)

Placing external plaster on rubble walls; wall preparation; placing techniques; single and multiple coat; opportunity for participants to apply single coat render using different mixes

Case studies of plasters and renders - failures and application. Introduction to cob and earth plasters

Day 4

Plaster and render conservation techniques; supporting, grouting, pinning and filling

Applying finish coat; fresco techniques; repairs to decayed plaster

The role of plaster analysis; techniques of sampling and study; uses and limitations.

Specifications for plaster and renders.

Review, discussion, questions and summary.

15.30 Issue of certificates and depart.


Arrival Day - this is the first date listed above

Courses start early evening. Residential students to arrive from 4pm, non-residential students to arrive by 6.45pm.

6.45pm: Welcome, followed by dinner (included).

8 - 9pm: First teaching session, attendance is essential.

Daily timetable

Classes 9.15 - 5pm, lunch is included.

From 6.30pm: Dinner (included for residential students).

Evening working - students may have access to workshops, but only with their tutor's permission and provided any health and safety guidelines are observed.

Last day

Classes 9.15am - 3pm, lunch is included.

Residential students are to vacate their rooms by 10am please.

(This timetable is for courses of more than one day in length. The tutor may make slight variations)

Course Materials

What students need to bring

  • Please remember to bring work clothes/overalls and shoes/boots for practical sessions. A torch and umbrella may be useful on the short walk to the Auditorium and Ruinette.

"I gained an excellent overall appreciation of the challenges involved in traditional plasters and renders. A good balance of practical and theoretical sessions."

Andrew, 2019


David Odgers

BCM Course Leader

David is Director of Odgers Conservation Consultants who provide support, advice and training for clients, architects, surveyors, local authorities and others involved in the conservation of historic structures.


Residential option available. Find out accommodation costs and how to book here.

Courses of interest

Sign-up to be the first to know

Sign up to our Short Course enews to hear about new courses, late availability and get creative inspiration delivered straight to your inbox.