Spandrel
In traditional building, the term 'spandrel' refers to the roughly triangular space or surface that is found between a curved figure and a rectangular boundary. It is thought to derive from from the Old French word 'spandre', meaning to spread.
Such spandrels can be found in a number of situations:
- The space between the curve of an arch and a rectilinear moulding.
- The space bounded by adjacent arches in an arcade and the horizontal moulding above.
- The space, where arches adjoin, between their crowns and springing lines. This is called a 'spandrel wall' if it is filled in.
- The space under a flight of stairs.
More recently, the term 'spandrel panel' has been used to refer to prefabricated triangular panels used in roof construction to separate spaces under the roof, or to complete the gable end of a roof. These panels can be installed quickly by crane, and mean that roofing contractors can complete wall elements under the roof rather than having to get brick or block layers to return to site.
![]() |
Carptrash at the English language Wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], from Wikimedia Commons |
The term spandrel panel may also be used to refer to cladding panels that fill the space above the head of a window on one floor and below the cill of the window on the next floor on high-rise buildings. These panels conceal the floor structure. If they are made from opaque or translucent glass, this may be referred to as spandrel glass.
Problems with spandrel panels were linked to the Lakanal House fire in 2009, and in October 2018, following the Grenfell Tower fire, the government published advice that building owners should test the combustibility of spandrel, window and infill panels if there is no documented evidence of their fire resistance and to remove them if they are considered unsafe.
It suggests that; "Spandrel panels can be provided for both aesthetic and functional purposes. Like the rest of the external wall, the panels are generally required to meet acoustic, thermal, moisture, and fire performance requirements. Such panels are not normally load bearing but are often designed to account for wind loading... The design and materials of panels varies between buildings; some are made of singular components such as cement particle board, other panels are composite products comprising outer facing materials bonded to an inner core."
The advice states; "Where the panel product type can be confirmed building owners should check the fire performance with the manufacturer by requesting test certification. Where there is no information about the panel or there is uncertainty, it will be necessary to investigate the panel composition by sample testing."
![]() |
Lakanal House |
PAS 9980:2022, Fire risk appraisal of external wall construction and cladding of existing blocks of flats – Code of practice, published by BSI Standards Limited in 2022, defines a spandrel panel as an: ‘infill panel that is located between the sill of a window and the head of the window below, or that spans the floor slab area in a curtain wall system… A spandrel panel commonly spans a compartment floor boundary and, therefore, is significant in terms of the scope for the fire to bypass fire barriers between floors.’
NB The term spandrel beam refers to an exterior beam that extends from one column to another, carrying an exterior wall load.
[edit] Related articles on Designing Buildings
Featured articles and news
Combating burnout.
The 5 elements of seiri, seiton, seiso, seiketsu and shitsuke.
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.