Scaffold Towers

Static and mobile

Towers come in two flavours. Static towers stand on base plates and stay put for the duration; mobile towers swap the base plates for braked castors so the whole structure can be repositioned. Both are free-standing structures which are self-supporting and do not depend totally on other structures for their rigidity and stability – which makes their own geometry and bracing critical.

Dimensions vary according to need, but standards should never be less than 1.2 m or more than 2.7 m apart, with foot ties fixed approximately 150 mm from the bottom of the standards. Except for the working platform, ledgers and transoms are fixed to the standards with right angle couplers.

The platform and access

Guard rails and toe boards are necessary on all four sides of a tower platform – there’s no “wall side” to lean on. Toe boards must rise at least 150 mm above platform level, and guard rails must be at least 910 mm above the platform, with the gap between toe board and guard rail not exceeding 470 mm. Any ladder should be fixed to the narrowest side of the tower, preferably inside the base area – climbing the outside of a tower is how towers get pulled over.

Height, base and stability

A tower’s stability is a straight contest between its height and its base dimensions. Proprietary aluminium towers state their maximum platform heights for indoor and outdoor use, and going higher means outriggers, ties, or choosing a different structure altogether. Wind is the great underestimated enemy: a sheeted or boarded tower left standing overnight in weather has featured in more than a few morning-after photographs.

Proprietary systems or tube and fittings?

Most towers on site today are proprietary aluminium systems: prefabricated frames that clip together in a fixed sequence, with the manufacturer’s instruction manual effectively serving as the structural design. They’re light, fast and hard to assemble wrongly if the method is followed. Towers built from traditional tube and fittings still have their place – odd heights, awkward footprints, integration with a larger scaffold – but they’re scaffolders’ work, demanding the same competence as any bespoke structure. Joints in the standards of either type should only be made with sleeve or parallel couplers, never a load-bearing coupler doing an end-to-end job it wasn’t designed for.

When a tower is the wrong answer

A tower suits one working position at height, or a handful of positions with clear ground between them. It stops being the right answer when the work runs along a whole elevation – that’s an access scaffold; when the work is overhead across a large area – that’s a birdcage; or when the loading outgrows a small platform. Forcing a tower to do a scaffold’s job is how towers end up overloaded, over-height and over on their side. The honest question at planning stage – how many positions, how much load, how long – picks the right structure before anyone orders the wrong one.

The insurance angle

Towers sit in an awkward middle ground – light enough that non-scaffolders erect them, tall enough that the consequences of getting it wrong are serious. Whether your teams build them from tube and fittings or assemble proprietary systems, make sure the activity is declared on your policy and that whoever puts them up can demonstrate competence to do so. The safety rules – inspection after erection and alteration, guarded platforms, trained users – apply at tower scale exactly as they do at street scale.

Scaffold tower FAQs