Jamb
The term 'jamb' typically refers to the vertical up-right components that form the sides or of door or window frames.
In relation to doors, on one side, the jamb bears the weight of the door through the hinges (the hinge jamb), whilst on the opposite side, the door latches, deadbolts and so on, when engaged, will usually extend into a recess in the jamb (the lock jamb). It is therefore important to ensure accuracy of the jamb’s plumb (verticality).
The joint between the door jamb and the surrounding walls will typically be concealed by a casing sometimes referred to as a door surround or architrave.
Window frames are typically formed by two side jambs, a horizontal cill across the bottom and a horizontal member across the top sometimes referred to as the head jamb or headjamb. On a window, the jambs can be fitted with jamb liners to improve air tightness. As with doors, a casing will generally be used to conceal the joint between the frame and the walls.
NB Short Guide, Fabric Improvements for Energy Efficiency in Traditional Buildings, published on 1 March 2013 by Historic Scotland, defines jamb as: ‘The vertical side posts used in the framing of a doorway or window. The outer part of the jamb, which is visible, is called the reveal.’
[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. ECA on better incorporation of 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.