What Is a Spandrel Beam?
A spandrel beam is the perimeter beam at each floor level that carries the exterior wall and the edge of the floor slab — the beam you see as the band between windows on a concrete or steel building's facade. It handles gravity loads from the wall and slab edge plus wind loads collected from the cladding, and it is a key element of the lateral system in many frame buildings.
Best price · Quotes back fast · PE stamps backed by Apex Grid Engineering
Structural role
Spandrels collect floor-edge loads and deliver them to columns, and in moment-frame buildings they are the beams that form the rigid frame with the columns — their stiffness directly sets the building's lateral drift. Deep spandrels also serve as the primary fire-protection challenge on the facade: the beam must maintain its rating while supporting the curtain wall anchors.
Coordination with the envelope
The curtain wall or cladding anchors to the spandrel, so the structural engineer and facade consultant coordinate anchor loads, embed locations, and deflection limits — cladding tolerates far less movement than the structure wants to allow. Slab edge and spandrel deflection under live load is limited specifically to protect the facade; this serviceability check often sizes the beam more than strength does.
Common detailing issues
Thermal bridging at exposed concrete spandrels (a continuous insulation and thermal break detail is needed for energy compliance), waterproofing at the slab-edge-to-wall interface, and fireproofing continuity where the spandrel passes behind the curtain wall. On renovations, cored holes through spandrels for new services need engineering review — spandrels in moment frames cannot be notched casually.
The bottom line
Spandrel beams carry the facade and floor edges and often form the moment frame. Coordinate cladding anchors and deflection limits early, detail the thermal break, and never core them without engineering review.
Torch Engineering PLLC · (480) 490-0064 · info@torchengineering.com — PE stamping backed by Apex Grid Engineering.