It is one of the most repeated sights on site: the scaffold is up, the platforms are boarded, the guardrails are fitted, and the crew is climbing to the top by standing on the braces. The erection is not finished: the way up is part of the scaffold.
What is a stair tower?
It is a vertical access unit built against or inside the scaffold, with its own platforms, stair flights and guardrails. It rises lift by lift, with a landing at each level, so the route up is not one steep ladder but a stairway with places to stop.
Why not a brace or a leaning ladder?
- A brace is a structural member, not a step. Standing on it strains the connection and disturbs how the system carries lateral load.
- A leaning ladder is for short, one-off tasks; on a façade where material is carried all day, fatigue and loss of balance are only a matter of time.
- You need both hands free. On a stair tower you can reach a guarded landing and set the material down; on a brace you cannot.
Where does it go?
The general rule is that work positions should be within walking distance of an access point. On a long façade one tower is not enough; if the crew has to walk to the far end of the scaffold every time, they will start taking the short way down, which means the braces.
Positioning follows the façade length, the number of lifts, how many people are working and where material is delivered from. The tower is set on a bay that does not block the route the material travels.
What to watch during erection
- Ground and base: the tower carries its own load; base plates, and timber packing where needed, spread it.
- Ties: a stair tower is tied to the structure too. A free-standing tower does not meet overturning safety on its own.
- Guardrails and toe boards: main guardrail, intermediate rail and toe board at every landing.
- Gaps at landings: no gap wide enough for a foot between the stair flight and the platform.
- The opening: the exit point needs a trapdoor or a side-entry arrangement; the opening is never left unguarded.
All of this forms part of the access and safety requirements in TS EN 12811. In the flanged system a stair tower is not a separate product: it is built from the same standards, ledgers and braces, with the stair flights and landing units added.
When you take delivery
Add the stair tower to your check list: are all the landings in place, are the guardrails fitted, is the tower tied to the structure, is there any movement in the flights? We listed ten checks before accepting a scaffold in a separate article.
Send us the façade length and the number of storeys, and we will work out how many access points the site needs along with the take-off.