Ashlar
Ashlar is a type of masonry which is finely cut and/or worked, and is characterised by its smooth, even faces and square edges. It can also be used to refer to an individual stone that has been finely cut and worked until squared.
Ashlar has been used in construction as an alternative to brick or other materials dating back to classical architecture, where it was often used to contrast with rustication (masonry with a purposefully rough or patterned surface).
Courses of ashlar can be horizontal, with blocks laid in parallel, or may be random with deliberately discontinuous vertical and horizontal joints.
Since ashlar blocks are precisely cut on all faces which are adjacent to other masonry, very thin joints can be achieved. The face of the block away from joints may be left rough and unpolished (known as quarry-faced), or may be polished or rendered decoratively. Mason’s drag is a form of decoration used on softer stone ashlar which involves small grooves applied by a metal comb-like device.
Mortar, or another joining material, is used to bind ashlar blocks together. Other methods of assembly such as metal ties can be used, in a process known as dry ashlar. Such a technique can be seen in the Inca architecture of Cusco and Machu Picchu.
In the UK, ashlar walling can be found in many historic buildings; one notable example being the Royal Crescent in Bath. It is also becoming more popular as a form of exterior cladding in urban commercial developments.
Society for the Protection of Ancient Buildings (SPAB) definition from their online Glossary : 'Finely dressed stone laid in regular courses with thin joints.'
[edit] Related articles on Designing Buildings
Featured articles and news
A now architectural practice looks back at its concept project for a sustainable oceanic settlement 25 years on.
Copyright and Artificial Intelligence
Government report and back track on copyright opt out for AI training but no clear preferred alternative as yet.
Embedding AI tools into architectural education
Beyond the render: LMU share how student led research is shaping the future of visualisation workflows.
Why document control still fails UK construction projects
A Chartered Quantity Surveyor explains what needs to change and how.
Inspiration for a new 2026 wave of Irish construction professionals.
New planning reforms and Warm Homes Bill
Take centre stage at UK Construction Week London.
A brief run down of changes intentions from April in an onwards.
Reslating an ancient water mill
A rare opportunity to record, study and repair early vernacular roofs.
CIOB Apprentice of the Year 2025/26
Construction apprentice from Lincoln Mia Owen wins this years title.
Insulation solutions with less waste for a circular economy
Rob Firman, Technical and Specification Manager, Polyfoam XPS explains.
Recycled waste plastic in construction
Hierarchy, prevention to disposal, plastic types and approaches.
UK Net Zero Carbon Buildings Standard V1 published
Free-to-access technical standard to enable robust proof of a decarbonising built environment.
Prostate Cancer Awareness Month
Why talking about prostate cancer matters in construction.
The Architectural Technology podcast: Where it's AT
Catch up for free, subscribe and share with your network.
The Association of Consultant Architects recap
A reintroduction and recap of ACA President; Patrick Inglis' Autumn update.
The Home Energy Model and its wrappers
From SAP to HEM, EPC for MEES and FHS assessment wrappers.
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.