A pane of facade glass is made carefully, tested and packed, and then it meets a construction site. Dust, moving plant, welding, rain and a tight programme all work against it. Many broken or scratched panes are not manufacturing faults but handling losses, and each one costs time as well as money because replacement can take weeks. Good site practice is not complicated, but it must be planned before the first delivery.
Plan delivery before the glass is made
Delivery should be agreed in the programme, not improvised. Confirm the date, the vehicle type, the access route, the unloading point and who receives the glass. Large panes need clear routes and enough space to turn, and they should not arrive before the facade frame is ready to receive them. Glass left waiting on site is glass at risk.
Mark each pane or rack with a reference that matches the drawings and the installation sequence. Inspect on arrival, with the delivery photographed and any damage recorded before the driver leaves. A damage claim made at the gate is far easier to settle than one made weeks later. Our article on facade installation sequence on site shows how delivery fits the wider programme.
Storage that keeps panes safe
Glass should be stored upright, in racks or on A-frames, at the angle recommended by the supplier. It should be off the ground on a firm, level base, with spacing material between panes so they cannot rub or stick together. Never stack flat unless the supplier specifically allows it, and never lean unprotected panes against a wall or column.
Protect the storage area from rain, because water trapped between panes can stain glass and attack edges and coatings. Shade matters too: direct sun on part of a stack can heat it unevenly and create stress. Keep the area fenced and away from vehicle traffic, and separate it from other trades whose work could damage or soil the glass.
Racks and crates should be opened only when the glass is needed, and only by people who know how the pack is built. Straps and frames can hold stored tension, and a rack that is released carelessly may let panes shift. Unpack one rack at a time, check each pane as it comes out, and re-pack or protect any pane that has to wait. A pane that is out of its protective packing for a week is at greater risk than one that stays inside it.
Handling and lifting
The edge is the weakest part of a pane. A chip or nick formed when a pane is set down hard on concrete may not show for days, then grow into a crack under thermal stress. Handling should use suction lifters or purpose-made lifting frames that are rated for the weight, with clean pads and regular checks of the vacuum. Panes should be set down on soft supports, never directly on hard ground.
Large panes are heavy and need planned lifting, with a clear exclusion zone below and trained operators. Wind can turn a big sheet into a sail, so lifting should stop when conditions are unsafe. Agree a method statement before the first lift and make sure everybody who handles glass has seen it. Our article on how facade glass thickness is chosen explains why thicker panes also mean heavier lifts.
Setting the glass in the frame
Once the pane reaches its opening, the way it is supported matters as much as how it was carried. Setting blocks sit under the lower edge, carry the weight and keep the glass off the metal. Their material, size and position come from the system supplier's instructions. They must not block drainage openings, and they must be placed where the frame is designed to take load.
Check that the glazing pocket is clean and free of debris before the pane goes in. A stone or burr under a pane can create a point load that cracks it hours or days later. Gaskets and beads should be fitted as the system instructions say, with compression that is even around the pane. Our article on sealants and gaskets in facades describes why those parts matter.
Do not use the glass as a working aid. A pane that is set in a frame is not a ladder rest, a handrail or a place to hang a lamp. Panes that look secure can be damaged at the edge by a load that would be trivial elsewhere. Ask installers to use the system's own temporary retention devices where a pane must be held before the beads and gaskets are complete, and never to leave an unretained pane overnight.
Protecting installed glass from other trades
Glass is often damaged after it is in place, by trades that work next to it. Welding sparks can fuse into the surface and leave permanent pits. Grinding dust, paint overspray, plaster and cement splashes leave marks that may not clean off. Alkaline cement runoff can etch glass if left to dry.
Protect installed panes with film, boards or screens, and put clear rules in place about hot work near the facade. Use bright markers or tape so people can see the glass, and keep scaffolding and materials from resting against it. If a pane is toughened, remember that its edges are still vulnerable, even though the centre is strong.
Write the protection plan into the site rules and the subcontract documents. Name who is responsible for protecting the glass at each stage, and who pays when a later trade damages it. Without that, every party assumes someone else is looking after it, and the damage is discovered at handover with no way to assign it. A short toolbox talk to each new trade before it starts near the facade costs little and prevents most of these arguments.
Thermal stress and shading
Glass can crack when one part is much hotter than another. This can happen if part of a pane is shaded by a canopy, scaffold or stored material while the rest sits in strong sun, or if a heater or hot air source is aimed at it. Dark coatings and tints absorb more heat and can increase the difference.
Avoid fixing temporary covers close to the glass in a way that traps heat. Avoid taping paper or board directly to the surface. When thermal risk is a concern, ask the glass supplier whether the specified type needs heat-soak testing or heat-strengthening. Our guide to laminated or toughened glass for facades gives a starting point.
Breakage on site: what to do
Even with good practice, some panes will break. The way the event is handled decides whether it becomes a minor delay or a recurring problem. Make the area safe first, because broken glass above head height is a hazard to anyone below. Then record the pane reference, the location, the time and the circumstances, and photograph the break pattern before anything is cleared away.
The break pattern can help show the cause. A crack that starts at an edge often points to handling or thermal stress, while a break from a corner or a hard impact point may suggest contact or an overloaded support. Keep the pieces if the cause is disputed, and tell the glass supplier promptly. Replacing the pane without asking why is a good way to break the next one for the same reason.
Where several panes fail in the same area, look at the setting, the frame alignment and the thermal conditions together, not one pane at a time. A pattern is a signal about the installation, not bad luck. Review the situation with the facade consultant before continuing with the same method.
Cleaning, inspection and handover
Clean the glass at the end of the work, not at the start. Use methods the supplier approves, and avoid blades or abrasive pads that can scratch a coating. Inspect each pane in good light for scratches, chips and stains, and record any that are found against the drawing. Agree an acceptance standard in advance so that a minor mark is judged on the same basis for the whole project.
Include a clear defect process in the handover. Panes can be tested at the end of the job, and some may have been cracked by earlier events. Our testing page explains what common facade tests measure, and our guide to facade warranty and defect liability explains how claims are usually handled.
A short site checklist
- Is delivery planned, with access, unloading point and receiver confirmed?
- Is storage upright, supported, off the ground and protected from weather and traffic?
- Are lifting devices rated and checked, with a method statement in place?
- Are setting blocks correct, and are drainage paths clear?
- Are installed panes protected from welding, grinding and wet trades?
- Is there a recorded inspection and a defect process before handover?
General guidance for orientation, not a specification. Applicable standards, values and details are confirmed per project with the facade consultant.
