Crizzling
Archaeological Evidence for Glassworking, Guidelines for Recovering, Analysing and Interpreting Evidence, published by Historic England in 2018, defines crizzling as: ‘A network of fine cracks that forms in unstable glass, particularly post-medieval lead glass.’
"The phenomenon often referred to as ‘crizzling’ is usually associated with vessel glass, and its occurrence in stained glass has not been studied extensively to date. Historically, it was thought that in windows the problem only occurred with green glass, leading to the name ‘green glass disease’, but we now know that is also occurs in other forms of glass. Purple crizzled glass is found in the windows of the nineteenth-century church of St John the Evangelist in the small North Yorkshire hamlet of Howsham." Merlyn Griffiths (York Glaziers Trust)
In the publication 'Conservation and Care of Glass Objects', by Stephen Koob (London, 2006) the process of deterioration is described in a number of stages: Firstly ‘sweating’ or ‘weeping’ caused by the appearance of alkali on the surface as droplets (in higher relative humidity) or as crystals (in lower relative humidity). The glass then becomes cloudy and opaque, as it develops a fine silvery network of cracks, known as ‘incipient crizzling’. The cracks become deeper and the surface of the glass begins to spall away, eventually leading to the fragmenting and disintegrating.
[edit] Related articles on Designing Buildings
Featured articles and news
Level 6 Design, Construction and Management BSc
CIOB launches first-ever degree programme to develop the next generation of construction leaders.
Open for business as of April, with its 2026 prospectus and new pipeline of housing schemes.
The operational value of workforce health
Keeping projects moving. Incorporating unplanned absence and the importance of health, in operations.
A carbon case for indigenous slate
UK slate can offer clear embodied carbon advantages.
Costs and insolvencies mount for SMEs, despite growth
Construction sector under insolvency and wage bill pressure in part linked to National Insurance, says report.
The place for vitrified clay pipes in modern infrastructure
Why vitrified clay pipes are reclaiming their role in built projects.
Research by construction PR consultancy LMC published.
Roles and responsibilities of domestic clients
ACA Safety in Construction guide for domestic clients.
Fire door compliance in UK commercial buildings
Architect and manufacturer gives their low down.
Plumbing and heating for sustainability in new properties
Technical Engineer runs through changes in regulations, innovations in materials, and product systems.
Awareness of the Carbon Border Adjustment Mechanism
What CBAM is and what to do about it.
The new towns and strategic environmental assessments
12 locations of the New Towns Taskforce reduced to 7 within the new towns draft programme and open consultation.
Buildings that changed the future of architecture. Book review.
The Sustainability Pathfinder© Handbook
Built environment agency launches free Pathfinder© tool to help businesses progress sustainability strategies.
Government outcome to the late payment consultation, ECA reacts.
IHBC 2025 Gus Astley Student Award winners
Work on the role of hewing in UK historic conservation a win for Jack Parker of Oxford Brookes University.