Scaffold Technical Guide • Gantries • Public Access
What Is a Gantry Scaffold?
A gantry scaffold is a scaffold structure arranged to create a clear opening, protected route or support zone beneath a scaffold deck, beam arrangement or working platform. It is commonly associated with pavement gantries, pedestrian routes, shopfront works, access over obstructions, temporary support openings and scaffold arrangements where loads must be carried around or over a route below.
Gantry scaffold arrangement
Definition
What is a gantry scaffold?
A gantry scaffold is a scaffold arrangement designed to form a clear opening, supported deck or protected access route beneath or through the scaffold. The term is commonly used where a scaffold has to span over a footway, entrance, driveway, loading area, access road, shopfront, obstruction or working route that must remain usable during the works.
It is not the same as a standard independent scaffold. A normal independent scaffold usually rises from ground level along the face of a building. A gantry scaffold has to deal with an opening, span, protected route, support point or public interface below the scaffold, so the beam arrangement, support towers, bases, bracing, tie positions, loading and clearance all become more important.
Technical Arrangement
How a gantry scaffold is built
A gantry scaffold is set out around the opening or route below. Standards or support towers carry load down to base plates, sole boards or designed supports. Beams or bridging members span the clear opening. Ledgers and transoms form the scaffold frame, scaffold boards form the working deck where required, and guardrails, toe boards, bracing and ties control the safe working area.
Vertical support points carry loads down to the ground, slab or supporting structure and must suit the imposed loads.
Scaffold beams, bridging beams or other designed members may be used to span the clear opening below.
The deck may form a working platform, protection deck or support level, depending on the purpose of the gantry.
Open edges need suitable guardrails, intermediate protection and toe boards where people or materials could fall.
Bracing, tying, returns or buttressing may be needed to control movement and maintain scaffold stability.
The opening below must be considered for headroom, width, pedestrian movement, vehicle movement or access requirements.
Use Cases
When is a gantry scaffold used?
Gantry scaffolds are used where scaffold access is needed but a route, entrance, shopfront, driveway, footway or obstruction cannot simply be blocked. They are common on public-facing works, high street premises, commercial frontages, refurbishment sites and areas where pedestrians, residents, operatives or vehicles still need a managed route beneath the scaffold.
Used where scaffold work has to be arranged over or beside a pedestrian route, subject to licensing and design requirements.
Can maintain controlled access beneath scaffold works for shops, offices, blocks or managed premises.
Useful where the scaffold must bridge over lower roofs, lightwells, basement openings, plant, entrances or other obstructions.
May be used with protection fans, debris protection or a protective deck where people or property below must be separated from the work above.
Planning
What needs to be checked before installing one?
A gantry scaffold should be planned around span, load path, clearance, public interface, supporting ground, tie positions, working platform duty and any requirement to protect the route below. It should never be treated as a simple name change from a standard elevation scaffold.
- Clear opening: the width, height and route below must be confirmed before the scaffold is set out.
- Span and beams: beam size, support points and the span between supports must suit the scaffold arrangement.
- Load path: imposed loads must transfer safely through beams, standards, bases, sole boards and supporting surfaces.
- Working platform duty: the required load class, boarded lifts, platform width and number of users must be specified.
- Public interface: pedestrians, residents, trading frontages, entrances, vehicles and deliveries may need segregation.
- Headroom and width: the route beneath the gantry must provide the clearance required for the intended use.
- Falling material risk: toe boards, brick guards, fans, debris netting or other protection may be required where appropriate.
- Stability: bracing, ties, returns, buttressing, kentledge or design input may be required depending on the arrangement.
- Highway matters: scaffolds over or beside a highway, including pavements, may require local authority licensing and traffic or pedestrian controls.
Technical References
Gantry scaffold guidance references
A gantry scaffold can fall into a more complex scaffold category because it may involve spans, public access, protection decks, beam work, pedestrian routes, support points or loading above a route below. The correct reference depends on the exact scaffold arrangement, the materials used and whether the arrangement is covered by a recognised standard configuration.
Relevant where the scaffold arrangement falls within recognised tube-and-fitting guidance or a compliant configuration generated for the scaffold type.
Relevant as a working scaffold performance reference for temporary works equipment, working platforms and loading principles.
Relevant where the gantry scaffold sits outside standard arrangements because of span, loading, support, geometry or public interface.
Relevant to safe methods of erecting, altering and dismantling scaffold structures while controlling fall risk.
Relevant where the gantry scaffold depends on ties, anchors or anchorage systems to maintain stability.
Relevant where a scaffold encroaches over or beside a pavement, road or other highway-controlled area.
Difference
Gantry scaffold, pavement scaffold and loading bay: what is the difference?
These terms can overlap on site, but they do not describe exactly the same thing. A gantry scaffold is normally about creating a clear opening, protected route or supported span. A pavement scaffold is usually a scaffold associated with pavement or public footway access. A loading bay is a scaffold platform built to receive and hold materials at a working level.
- Gantry scaffold: focuses on spanning, supporting or protecting a route or opening below.
- Pavement scaffold: focuses on scaffold work beside or over a pavement or public footway.
- Loading bay: focuses on receiving, storing and transferring materials safely at height.
- Protection fan: focuses on deflecting or containing falling material risk where appropriate.
Limitations
When does a gantry scaffold need design input?
Many gantry-type arrangements should be reviewed carefully because they may involve unusual spans, public routes, large openings, protection decks, heavy loading, highway controls, beam work or restricted support points. Outside recognised standard configurations, competent design and calculations are required.
- Public routes: pedestrian routes, highways and shopfront access usually need additional planning and controls.
- Large spans: longer clear openings can require beam design, support checks and leg load review.
- Heavy loading: stored materials, equipment and deck loading can change the scaffold duty requirement.
- Unsupported openings: basements, lightwells, lower roofs, voids and weak slabs may affect base support.
- Sheeting or netting: wind loading can alter the stability requirement of the scaffold.
- Alterations: removing ties, changing beams or changing access routes can affect stability and may need further review.
FAQ
Gantry scaffold questions
Is a gantry scaffold the same as a loading bay?
No. A loading bay is mainly for receiving and holding materials at height. A gantry scaffold is normally about spanning over a route, maintaining clearance below or forming a protected route or support arrangement.
Is a pavement gantry likely to need design?
Normally, yes. HSE identifies pavement gantries as structures normally requiring bespoke design.
Can a gantry scaffold be used over a shop entrance?
It can be considered where a clear route or protected access is needed below the scaffold, but the arrangement must be planned around loading, headroom, public interface, protection and stability.
What information is needed before planning one?
Useful information includes the span, clearance required, intended use, loading, scaffold height, route below, ground conditions, building tie options, highway restrictions and whether the scaffold needs sheeting, fans or debris protection.
Need a gantry scaffold assessed?
BlackFox Scaffolding can review whether a gantry scaffold is the right method for public-facing works, shopfronts, access routes, covered walkways, obstructions, temporary support openings and contractor scaffold access.