What Actually Holds a Facade Up

A self-supporting masonry veneer stands on a support at its base and is restrained sideways by anchors reaching back to the frame. Its weight runs down through itself to that bearing, and where its weight is picked up again higher in the building, an angle or ledge takes it back into the structure.

A brick slip facade inverts that. There is no continuous bearing line; each facing hangs from its connection to the carrier, and the carrier hangs from its fixings, so the weight is distributed into fixings all the way up the elevation. A bonded facade distributes it differently again, through a continuous adhesive layer over the whole back of every unit. A precast or sheeted facade concentrates it into a small number of support points, with everything else restraining only.

The records give tests that can be made without opening anything. At the bottom of the wall, a veneer stands on something — a footing, a plinth or a supporting angle — while a slip facade has no continuous bearing. At corners and reveals, a veneer turns with a whole brick and shows a genuine return; a slip facade turns with a purpose-made angle piece, and the reveal is a facing applied to a lining.

At a floor, a hung precast cladding panel shows a movement joint at every storey precisely so the structure can move without the panel following it, and a bracket rather than a bearing. A loadbearing panel continues the load path, with floors bearing on it. On a sheeted metal wall the sheets lap over one another and are fixed through to rails, rather than being jointed at intervals like panels.

A veneer's anchors are invisible and the leaf will stand until it is loaded, so a veneer that appears sound can be inadequately anchored. The support line is its other weak point: the junction record describes a horizontal crack with spalled brick faces immediately beneath a support as the movement question, arising where the joint under the angle has been mortared solid and the release the design relied on never happened.

A slip facade fails at the connection between facing and carrier, and a displaced facing is not like a spalled brick: it exposes a carrier that was never intended to be seen or weathered. A bonded facade's defining condition is loss of adhesion at height, where a hard unit on a vertical surface is retained only by its grout, and a facade whose grout is sound tells nobody anything about the bond behind it.

A panel facade fails where restraint becomes support. Hold a panel rigidly at more than one bearing point and the structure's shortening and deflection are transmitted into a stiff cast unit, which responds by cracking, usually at its weakest section around an opening. On a rainscreen, the same problem reads at one panel rather than across a run: a single panel sitting proud or dropped, joints around it gone uneven, fixing heads showing at the face.

Several of these facades depend on keeping two duties apart. On a precast facade a small number of points take the weight while others hold the panel in plane without adding a second load path, and slotted holes and sliding connections exist to keep those duties separate — but only while their clearances remain free. On a veneer, an anchor has to restrain the leaf outward and inward while yielding along the face of the wall.

The record names the instinct that defeats this: adding fixings to a hung panel to make it feel more secure removes the freedom the design relied on to absorb structural movement. The same logic applies along a rainscreen rail run, where some connections deliberately carry weight and others restrain the rail without preventing it sliding, and which is which is invisible once the panels are on.

A factory product arrives accurate; a frame built on site arrives within a range. That difference has to be taken up somewhere, and if adjustment was not designed into the fixings it will be taken up in the joints instead. On a precast facade that makes a setting-out problem into a water problem, because the joint is also the weathering element.

On a rainscreen the same failure reads differently. Where the setting-out was not recovered at the bracket-to-rail connection, the joint lines taper across the elevation and the error accumulates toward one end rather than appearing at the panel where it started.

All of these records converge on one warning. Fixing back to cladding panels rather than to a nominated backing element loads a component designed only to carry itself. On a slip facade, fixing anything into it later means fixing into a carrier rather than into a wall. On a curtain wall, fixing to a mullion after completion loads a member designed for wind and may cross the isolating component within its section.

That is why the shading record describes the question as what the arm actually reaches, rather than what it appears to be fixed to, and treats cladding fixings quietly becoming structural as a change nobody records and no one inspects.