The facade is a load that hangs off the building’s edge, and edge beams live their whole lives carrying it: a line load equal to the cladding’s weight times the storey height it supports, applied not on the beam’s centreline but outboard of it, with wind pushing and pulling through the same connections. StructLoads treats the facade as the perimeter line load it is, at its real weight and its real eccentricity, which is what keeps the edge members honest, because the edge of the floor plate is where three understatements meet: cladding weights that vary by a factor of ten between systems, an eccentricity that turns weight into torsion, and deflection limits far stricter than the beam would need for itself.
What a facade weighs, per metre of edge
Cladding weights per square metre of wall span an order of magnitude, and the edge beam’s line load is that number times the supported height. Glazed curtain walling runs 0.4 to 1.0 kPa of wall: light, hung storey by storey, the gentlest case. Insulated metal panels and rainscreen systems sit near 0.3 to 0.8 kPa plus their framing. Brick veneer is the traditional heavyweight: a 100 mm clay brickwork skin weighs about 1.8 to 2.2 kPa of wall, so a 3.5 m storey of it delivers 6 to 8 kN/m along the shelf angle. And architectural precast panels top the range: 150 to 200 mm of concrete is 3.6 to 4.8 kPa, a full storey of it 12 to 17 kN/m, with individual panels of several tonnes arriving as pairs of point loads at their bearing brackets rather than as a smooth line.
The wall line load arithmetic is the same as for any wall, with one facade-specific decision attached: which storey’s edge carries which band of wall. Storey-hung systems, curtain walls, most rainscreens, load each floor with one storey height. Ground-supported veneer stacks its whole height onto the foundation with the floors only restraining it laterally, until a shelf angle interrupts the stack and hands everything above back to the edge beam. Mixed systems change hands at movement joints, and the takedown must follow the actual support diagram, not a habit: a brick facade with shelf angles at every second floor loads alternate edge beams with two storeys of veneer each, 12 to 16 kN/m, and the beams between with none.
| Cladding system | Weight per m² of wall | Line load per 3.5 m storey |
|---|---|---|
| Curtain wall, glazed | 0.4-1.0 kPa | 1.4-3.5 kN/m |
| Metal panel / rainscreen | 0.3-0.8 kPa | 1-3 kN/m |
| Brick veneer, 100 mm | 1.8-2.2 kPa | 6-8 kN/m |
| Architectural precast, 150-200 mm | 3.6-4.8 kPa | 12-17 kN/m |
Eccentricity: the weight arrives with a twist
No facade hangs on the beam’s centreline. Brick sits on a shelf angle bolted to the slab edge, its bearing 100 to 200 mm outboard; precast bears on corbels or brackets with similar offsets; curtain wall brackets stand the mullion line off the structure by whatever the detail drew. Weight times offset is a torque per metre of edge: 8 kN/m of brick at 150 mm eccentricity is 1.2 kNm/m of torsion trying to rotate the edge beam outward, continuously, for the life of the building. Spandrel beams resolve it in torsion, a limit state concrete beams meet with closed stirrups and steel beams meet reluctantly; slabs at their edges resolve it as a local moment; and the honest alternative, where details allow, is a couple, the bracket designed to push and pull two fixing levels so the structure sees paired horizontal forces instead of a twist. Either way, the eccentricity is part of the load, and a takedown that records 8 kN/m while dropping the 150 mm has recorded half the problem, the same lever-arm honesty that cantilever edges demand.
Wind arrives through the same connections, both ways. The facade collects the wind pressure over its tributary band and delivers it to the floor edges as horizontal line or point loads: a 1.0 kPa design pressure on a 3.5 m band is 3.5 kN/m pushing or, on suction faces and at corners where cladding pressures peak, pulling the connections outward. The edge member carries this into the diaphragm; the brackets carry tension; and the corner regions, where local cladding coefficients run highest, load the corner columns and their edge beams with the worst of both ledgers, most facade weight per support and most wind per area.
Deflection: the strictest master the edge beam serves
Facade support is usually the edge beam’s governing serviceability case, because cladding tolerates far less movement than structure does. Brick veneer cracks over a sagging shelf angle; stick curtain walls rack when floor edges deflect differentially; precast joints open and close with the structure’s breathing; and sealant joints have finite travel. Typical project criteria hold facade-supporting edges to span/500 or an absolute few millimetres under the loads applied after cladding installation, several times stricter than the span/250 the beam would owe a plastered ceiling. The phrase after installation is the operative subtlety: the cladding never feels the deflection that happened before it arrived, so the design ledger splits the beam’s history at the day the panels hang, and only the increments after that day, live load, creep, the neighbouring bays’ fit-out, count against the facade’s allowance. Long-term creep on concrete edges and the timing of the superimposed dead loads therefore sit inside what looks like a simple stiffness check.
The same logic runs vertically: a curtain wall hung at each floor must absorb the relative shortening of the columns it passes, elastic, creep, and shrinkage in concrete towers, through its stack joints, and the facade engineer’s movement schedule is downstream of the structural engineer’s predicted column load history. Facade and structure are one system with two designers, and the interface document, loads one way, movements the other, is where the system either works or leaks.
Brackets, panels, and the points inside the line
The line load is a convenient fiction over a truer picture: most facades reach the structure at discrete brackets, and the heavier the system, the less the fiction holds. A four-tonne precast spandrel panel bears on two corbels, 20 kN each, placed wherever the panel joints fell relative to the beam’s span, and a panel joint landing mid-span puts both neighbouring panels’ bearings there, 40 kN at the worst point rather than 10 kN/m everywhere. Curtain wall brackets at 1.5 m centres blur back toward a line; precast at 6 m centres does not, and the cladding system’s setting-out drawing is therefore a structural load document, worth reading before the edge beam is sized rather than after the panels are cast.
Openings repeat the same lesson at the next scale down: where the facade band is interrupted by a storefront or a ribbon window, the wall above the opening arrives through a lintel as two end reactions on the flanking structure, and the edge member’s line load develops gaps and spikes accordingly. The takedown habit that absorbs all of this: model the facade at line-load resolution for the perimeter totals and the column accumulation, then check the specific edge members against the actual bracket and bearing positions once the setting-out exists, the two-pass rhythm that catches the mid-span corbel before it becomes a site query.
A worked example: one spandrel, brick over a showroom
Take an edge beam, illustrative round numbers throughout: an 8 m spandrel supporting one 3.5 m storey of brick veneer at 2.0 kPa on a shelf angle 150 mm outboard, plus its 2.4 m tributary strip of floor at 5 kPa dead and 3 kPa live. The facade contributes 7 kN/m of permanent line load and 1.05 kNm/m of torsion; the floor strip contributes 12 kN/m dead and 7.2 kN/m live on the centreline. The beam’s bending design barely notices which system the architect chose; its torsion design exists entirely because of the brick, 8.4 kNm of accumulated twist to each support, demanding closed stirrups and a torsion-capable connection detail.
Now the serviceability split. Under floor live load alone, the beam deflects, say, 9 mm at mid-span: acceptable against span/250 for the structure, but the brick’s allowance is span/500 = 16 mm minus what creep will add after installation, so the timeline matters: if the veneer goes up before the screeds and fit-out, those permanent increments spend the brick’s budget too, and the beam that passed every strength check needs stiffening for a wall that was not yet there when it was poured. Multiply the lesson across the perimeter and down the multi-storey takedown: the facade is 5 to 15 percent of a tower’s gravity, all of it on the edge members, all of it eccentric, all of it deflection-critical, and StructLoads carrying it as an explicit perimeter load per storey is what makes the edge columns’ premium and the spandrels’ twin masters visible in one place.
Key takeaways: facade and cladding loads on edge beams
Facade weight spans a factor of ten, curtain wall at 1.4 to 3.5 kN/m per storey, brick at 6 to 8, precast at 12 to 17, and it lands where the support diagram says, storey-hung, ground-stacked, or handed over at shelf angles, not where habit assumes. The weight arrives eccentric, 100 to 200 mm outboard, making torsion or force couples part of the permanent load, and wind returns through the same brackets in both directions. Deflection after installation, typically span/500, governs edge stiffness more often than strength, so carry the facade as an explicit, eccentric, per-storey perimeter load in the takedown.
Quick answers
How do facade and cladding loads act on edge beams?
As a permanent line load equal to the cladding weight times the supported storey height, curtain wall 1.4 to 3.5 kN/m, brick veneer 6 to 8, architectural precast 12 to 17, applied 100 to 200 mm outboard of the beam, so torsion or a resolving force couple accompanies the weight, and wind pushes and pulls horizontally through the same connections. StructLoads carries it as an explicit eccentric perimeter load per storey, following the actual support diagram of shelf angles and brackets.
Which floor carries the facade’s weight?
Whichever the support diagram says: storey-hung systems like curtain walls load each floor with one storey band; ground-supported brick stacks to the foundation with floors only restraining it, until a shelf angle hands everything above back to an edge beam; and precast bears where its brackets sit, sometimes skipping floors. A facade with shelf angles every second storey loads alternate beams with double bands and the others with none, and the takedown must follow the detail, not an assumption.
Why does cladding cause torsion in edge beams?
Because it hangs outboard: brick shelf angles and precast corbels bear 100 to 200 mm beyond the beam’s centreline, and weight times that offset is a continuous torque, 8 kN/m at 150 mm is 1.2 kNm per metre, twisting the spandrel outward permanently. Concrete answers with closed stirrups, steel reluctantly, and good details convert the twist into a push-pull couple across two fixing levels. Dropping the eccentricity from the record halves the problem on paper only.
What deflection limit applies to facade-supporting beams?
Commonly span/500 or an absolute limit of a few millimetres, measured only over deflections occurring after cladding installation, since the wall never feels earlier movement. That is roughly twice as strict as ordinary finishes demand, and it is evaluated including creep and every permanent increment added after the panels hang, which makes construction sequence part of the stiffness check. Vertically, hung facades must also absorb predicted column shortening through their stack joints.
When should you not treat the facade as a minor allowance?
Almost always on heavy systems and always at the edges: brick and precast put 6 to 17 kN/m of eccentric permanent load on members that also collect peak local wind, and the facade totals 5 to 15 percent of a tower’s gravity, concentrated entirely on the perimeter. An allowance smeared into the floor rate misses the torsion, the deflection timing, and the edge columns’ premium. Carry it as what it is: an eccentric perimeter line load with its own serviceability contract.