Lath and plaster
Lath and plaster is a technique which was used to finish interior walls and ceilings from the early-18th until the early-to-mid-20th century. It was then generally superseded by drywall techniques and plasterboard.
The process involved laths (thin strips of timber) nailed to timber joists or posts and then covered with built-up layers of plaster. Laths typically measure 25 mm x 6 mm, and are positioned about 6 mm apart from each other to allow the plaster to penetrate into the gaps between them.
Typically three coats of plaster would then be applied:
- A ‘render’ layer about 6 mm thick to bond to and fill the gaps between the laths.
- A ‘floating’ layer about 6 mm thick to provide a relatively smooth surface for the third layer.
- A ‘setting’ layer about 3 mm thick to provide a completely smooth finish for decoration.
The first and second layers typically used a 1:3 lime putty to clean, sharp sand mixture. Animal hair was often added to assist with binding. The mixture for the third layer was usually a 3:1 lime putty to fine sand mixture or lime putty on its own.
As time went on, gypsum or cement was added which helped to reduce the setting time between layers.
The advantage of using lath was that it allowed for ornamental or decorative shapes, and could provide sound insulation and fire resistant properties.
However, it was a skilled craft and was a time-consuming activity and so was largely replaced by the use of pre-manufactured plasterboard towards the middle of the 20th century.
[edit] Related articles on Designing Buildings
Featured articles and news
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.
The emancipation of women in art.
Call for independent National Grenfell oversight mechanism
MHCLG share findings of Building Safety Inquiry in letter to Secretary of State and Minister for Building Safety.
The Architectural Technology Awards
AT Awards now open for this the sixth decade of CIAT.
50th Golden anniversary ECA Edmundson awards
Deadline for submissions Friday 30 May 2025.
The benefits of precast, off-site foundation systems
Top ten benefits of this notable innovation.
Encouraging individuals to take action saving water at home, work, and in their communities.
Takes a community to support mental health and wellbeing
The why of becoming a Mental Health Instructor explained.
Mental health awareness week 13-18 May
The theme is communities, they can provide a sense of belonging, safety, support in hard times, and a sense purpose.
Mental health support on the rise but workers still struggling
CIOB Understanding Mental Health in the Built Environment 2025 shows.
Design and construction material libraries
Material, sample, product or detail libraries a key component of any architectural design practice.