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
Moisture, fire safety and emerging trends in living walls
How wet is your wall?
Current policy explained and newly published consultation by the UK and Welsh Governments.
British architecture 1919–39. Book review.
Conservation of listed prefabs in Moseley.
Energy industry calls for urgent reform.
Heritage staff wellbeing at work survey.
A five minute introduction.
50th Golden anniversary ECA Edmundson apprentice award
Showcasing the very best electrotechnical and engineering services for half a century.
Welsh government consults on HRBs and reg changes
Seeking feedback on a new regulatory regime and a broad range of issues.
CIOB Client Guide (2nd edition) March 2025
Free download covering statutory dutyholder roles under the Building Safety Act and much more.
AI and automation in 3D modelling and spatial design
Can almost half of design development tasks be automated?
Minister quizzed, as responsibility transfers to MHCLG and BSR publishes new building control guidance.
UK environmental regulations reform 2025
Amid wider new approaches to ensure regulators and regulation support growth.
The maintenance challenge of tenements.
BSRIA Statutory Compliance Inspection Checklist
BG80/2025 now significantly updated to include requirements related to important changes in legislation.
Shortlist for the 2025 Roofscape Design Awards
Talent and innovation showcase announcement from the trussed rafter industry.