Balconies, bay windows, canopies: getting the scaffold past obstacles
On a drawing, a facade scaffold is a straight row of identical bays. On site, there is a canopy over the shop door, a balcony projecting 1.60 m on the first floor, a bay window at the corner and a garage entrance that must stay usable. Each of these interrupts the direct path of load from deck to ground. The skill lies in rerouting that load without making the scaffold less stiff or opening a dangerous gap to the wall.
Survey first: list every obstacle
Walk round the building before planning and note everything that projects from the wall or blocks the ground. Measure projection, width and height above ground, and put it on a sketch of each elevation.
| Obstacle | The difficulty | Usual solution |
|---|---|---|
| Canopy over an entrance | No room for standards; doorway must stay open | Lattice girder over one or two bays, fan or covered walkway below |
| Balcony on an upper floor | Scaffold must stand in front of, beside or on the slab | Scaffold in front of the balcony edge, gap to wall closed with inside brackets |
| Bay window, oriel, projecting stair core | Facade steps forward; one deck cannot reach both faces | Scaffold follows the outline, or stays straight with brackets |
| Driveway, garage door | Vehicles must pass | Passage frame or lattice girder with enough headroom |
| Extension, conservatory, garage | Scaffold would have to stand on a roof | Standards in front, girders over the extension |
| Steps, ramps, lightwells | Different ground levels | Base jacks, compensation frames, bridging onto firm edges |
Three answers to every obstacle
Each deck passes its load to ledgers or frame heads, then down the standards to the ground. If a standard is missing, the load has to take another route:
- Move it: the standard shifts sideways or outwards. Simplest, but it changes bay lengths or the wall gap.
- Bridge it: a lattice girder spans the gap and hands its load to the two neighbouring standards, which then carry the lifts above the bridged bay as well.
- Support it from above: the scaffold starts above the obstacle and is carried on brackets, beams or outriggers that transfer forces to adjacent scaffold or the building.
A modular scaffold handles this well, because ledgers and braces connect in several directions at every node. Frame scaffolds manage the same solutions, but need more extras such as girders, tubes and couplers.
Entrances and canopies: the lattice girder
Example: a corner shop has a 4.2 m wide entrance canopy in a 14 m frontage. With 2.57 m bays, one frame line would land right on the canopy. Instead, that frame line stops beneath the girder level. A girder over two bays, about 5.1 m, is fitted at the first lift and carries the frames above. The two frame lines either side of the entrance stand on the ground and each takes part of the load of the missing one.
- Connect both chords. A girder works as a truss only if top and bottom chords are fixed to the scaffold, with the couplers or claws the system specifies.
- Restrain it sideways. The compressed chord must be braced against buckling, for example by plan bracing or a second girder on the inner line.
- Strengthen the neighbours. Check base jacks and their extension; use larger sole boards on soft ground.
- Add ties. Many instructions require extra ties beside a bridged bay.
- Protect the doorway. People pass beneath. A protective fan or close-boarded lift above stops tools and mortar falling on them.
Where only pedestrians need to get through, some systems offer a passage frame with a wider clear opening in the bottom lift. For vehicles, a girder is almost always needed. Girders in various lengths are in our lattice girder section.
Balconies and bay windows
A first-floor balcony typically projects 1.20–2.00 m. There are three options:
- Scaffold in front of the balcony edge along the whole elevation. Good for the balustrade and slab, but elsewhere the deck is far from the wall. Close the gap with inside brackets and extra boards; see widening the scaffold.
- Step the scaffold out at the balcony. Close to the wall elsewhere, offset forward at the balcony. Saves brackets but adds two corners to brace and tie.
- Stand on the balcony. Tempting but risky: a cantilevered slab is designed for people and furniture, not for concentrated loads from several lifts, and waterproofing and tiles suffer. Only after an engineer has approved it, with load-spreading boards.
A bay window can be followed, with short runs returning to the main wall at each side and properly connected corners so no gap opens. Or the scaffold stays straight in front and the set-back wall is reached with inside brackets, which is quicker where the projection is no more than one bracket width. If an oriel starts on the first floor above the pavement, the scaffold either stands forward from the start with inside brackets on the lower lifts, or is widened outwards with brackets at oriel level.
Extensions, garages and level changes
Standing the scaffold on a garage roof usually fails on capacity: light flat roofs, profiled sheet or glass carry no scaffold load. A solid concrete slab may work after checking, with boards that protect the waterproofing. The better route is often to place standards in front of the extension and bridge over it with girders to the house wall. Small level differences are taken up with base jacks, larger steps with compensation frames or staggered standards. Never stand a standard on a lightwell grating; bridge onto firm edges.
When an engineer has to be involved
The manufacturer's instructions usually cover girders over one or two bays and brackets in certain lifts. Anything beyond that leaves the standard configuration: girders over more bays or with more lifts above, a whole scaffold supported over an extension, projections over a pavement with a fan added, or scaffolds on balconies, roofs or cellar slabs. Such cases require a structural calculation for the specific situation, prepared by a competent person and kept on site with the scaffold plan. Allow a few days for it and supply photos, dimensions and the instructions for your system.
Mistakes to avoid
- A frame stood briefly on a canopy that was never designed for point loads.
- Girder fixed by the top chord only, so it does not act as a truss.
- A 50 cm gap left at the corner between bay window and main wall.
- The standard next to a driveway carrying almost double load on the same small base plate in a lawn.
- Outside brackets strung together to reach an oriel, without braces or design.