Can You Use a Scaffold Tower on Uneven Ground?

Scaffold towers provide a practical and secure working platform for decorating, maintenance, construction and repair work. However, their stability depends heavily on the surface beneath them.

A tower that has been assembled correctly can still become unsafe if it is positioned on soft, sloping or uneven ground. Before erecting a scaffold tower, the condition of the ground must therefore be assessed carefully.

The Health and Safety Executive states that a tower should rest on firm, level ground, with its locked castors or base plates properly supported. The Work at Height Regulations also require any surface supporting a work-at-height structure to be stable, sufficiently strong and suitable for the loads placed upon it.

So, can you use a scaffold tower on uneven ground?

In some situations, a tower can be safely levelled using the correct adjustable legs and equipment. However, adjustable legs have limited travel and cannot make unsuitable ground safe. The tower must remain fully supported, level, vertical and configured according to the manufacturer’s instructions.

Why Ground Conditions Matter

A scaffold tower transfers its weight through a relatively small number of contact points. These normally include:

• Four castors or base plates
• The feet of any stabilisers
• The feet of any outriggers
• Additional supports included in the manufacturer’s configuration

Each contact point must be properly supported.

The surface must be capable of carrying the combined weight of the tower, users, tools and materials without sinking, moving or collapsing. If one castor or stabiliser moves, the tower can lean or become unstable.

PASMA guidance explains that each ground contact point needs a solid, strong and stable supporting surface. Loose gravel, mud, sand and similarly weak surfaces may not provide sufficient support because components can move or sink under load.

Uneven ground can also cause the tower to lean. Even a small incline becomes more significant as the tower increases in height, potentially moving the working platform away from the centre of its base.

You should never assume that a surface is suitable simply because it appears solid.

What Counts as Uneven Ground?

Uneven ground can include any surface that prevents all the tower’s castors, base plates and stabilisers from sitting at the correct level.

Common examples include:

• Sloping driveways
• Uneven concrete floors
• Paved areas with raised or sunken slabs
• Gardens and lawns
• Gravel surfaces
• Compacted soil
• Building sites
• Kerbs and changes in level
• Warehouse floors containing channels or drainage points
• Ground near excavations, trenches or manholes
• Steps and stairways

Some of these surfaces can be managed with the correct tower and accessories. Others may require a different access solution entirely.

A site-specific risk assessment should always determine whether the tower can be used safely.

Can Adjustable Legs Level a Scaffold Tower?

Adjustable legs are designed to level a scaffold tower when there are relatively small differences in the ground height.

Each leg can be extended independently, allowing the base of the tower to be brought level. The tower should then be checked in both directions, normally using a spirit level, before construction continues.

However, adjustable legs must only be used for levelling.

They must never be extended simply to increase the tower’s platform height. PASMA advises that at least one adjustable leg should remain at minimum extension and that additional tower height should only be achieved by using the correct frames and components.

Extending all four legs unnecessarily can increase the overall height of the tower’s base and may create a configuration that has not been approved by the manufacturer.

When using adjustable legs:

1. Begin with the legs at their lowest practical setting.
2. Position the tower base on the intended working area.
3. Extend only the legs required to correct the difference in ground level.
4. Use a spirit level to check the tower in both directions.
5. Confirm that each castor or base plate is fully supported.
6. Fit the required braces, platforms and stabilisers.
7. Recheck the tower after assembly and before use.

Never exceed the adjustment permitted by the tower’s instruction manual.

Can You Use a Scaffold Tower on a Slope?

Using a scaffold tower on a slope requires careful planning.

A very gentle slope may sometimes be accommodated using the tower’s adjustable legs, provided the required adjustment remains within the manufacturer’s limits and the resulting tower is stable, vertical and properly supported.

A steeper slope presents considerably more risk.

PASMA states that there is no universal answer because site conditions vary. A risk assessment must determine whether a tower can be assembled safely. Its guidance also indicates that base plates can sometimes be more suitable than castors on sloping ground and that additional measures, such as tying the structure, may be necessary in specialist configurations.

A standard mobile scaffold tower should not be improvised into a tied or specially supported tower without the appropriate design, components and competent supervision.

Where the slope exceeds the available adjustment of the legs, stop and choose another solution. This may include:

• Preparing a properly levelled base
• Using an approved stepped configuration
• Selecting a specialist tower designed for changes in level
• Using a tied tower designed for the location
• Choosing another form of access equipment

Do not force the tower to fit an unsuitable surface.

Can You Use a Tower on Grass or Soil?

Grass and soil can be deceptive. The surface may look firm while the ground underneath remains soft, wet or uneven.

The tower may appear stable when it is first erected but begin to sink after users, tools and materials are added. Rain can also soften previously firm ground and change the tower’s stability during the working period.

Before using a tower on grass or soil, consider:

• Whether the ground has been recently disturbed
• Recent and forecast rainfall
• Underground services
• Voids, drains or inspection chambers
• The weight of the assembled tower
• The number of users
• The weight of tools and materials
• Whether stabiliser feet can be properly supported
• Whether the ground could become softer during use

A tower should not be used when the ground cannot reliably support every contact point.

Placing random boards beneath the tower does not automatically make soft ground safe. Any load-distribution solution must be suitable for the tower, appropriately sized and assessed by a competent person.

Can You Use a Scaffold Tower on Gravel?

Loose gravel is generally a poor surface for a mobile tower because castors and stabiliser feet can move, twist or sink.

The surface may also prevent the castor brakes from working effectively. A wheel can be locked against rotation while still sliding across loose material.

Small decorative stones are particularly unsuitable because they can shift as the tower is loaded or as users climb it.

A properly prepared and compacted area may be required before a tower can be erected. The prepared surface must support every castor, base plate and stabiliser rather than only the main tower legs.

Can You Place Bricks Under a Scaffold Tower?

No. Bricks, concrete blocks and similar improvised packing must not be used to level or support a scaffold tower.

The HSE specifically advises against using bricks or building blocks to carry the weight of any part of a tower.

Improvised packing can:

• Crack under load
• Slide out of position
• Create an unstable stack
• Concentrate loads incorrectly
• Prevent castors or base plates from sitting properly
• Make the tower difficult to level accurately

Use only the tower’s approved adjustable legs, castors, base plates and manufacturer-authorised components.

Timber offcuts, pallets, paving blocks and pieces of scaffold board should not be treated as substitutes for the correct equipment.

Castors or Base Plates?

Most mobile scaffold towers are fitted with locking castors, allowing them to be repositioned when the tower is not occupied.

Castors are suitable only when they are:

• Compatible with the tower
• Undamaged
• Properly attached
• Fully supported
• Locked before the tower is climbed or used

Base plates may be used with certain tower systems and configurations where mobility is not required. On sloping or difficult surfaces, they can sometimes provide a more appropriate contact point than wheels, but only where permitted by the tower manufacturer.

A tower must never be used with the bottom of its frames resting directly on the ground. PASMA guidance states that castors or base plates must be fitted to the base of every upright.

Do not remove the wheels from a standard tower and place the frames on timber or packing materials.

The Importance of Stabilisers and Outriggers

Stabilisers increase the effective footprint of the tower and help resist overturning. They must be fitted in the positions and configuration specified in the instruction manual.

The stabiliser feet must also sit on firm, secure ground. It is not enough for the tower’s four main castors to be supported if a stabiliser is positioned over loose soil, a drain cover or an unsupported edge.

PASMA advises that stabilisers are an essential part of a freestanding EN 1004 tower configuration rather than an optional extra.

When working on uneven ground:

• Check the position of all stabiliser feet
• Ensure each foot is carrying load correctly
• Keep stabilisers clear of openings and edges
• Use the correct size for the tower height
• Do not alter the stabilisers
• Do not substitute a different model
• Recheck them if the tower is moved

Stabilisers do not compensate for weak or unstable ground. They require secure support themselves.

Using a Scaffold Tower Near Kerbs and Steps

A conventional mobile tower should not be balanced across a kerb or change in level unless the manufacturer provides a suitable approved configuration.

Where one pair of castors sits on the pavement and the other pair sits on the road, the difference may exceed the safe adjustment of the legs. The lower side may also be exposed to passing vehicles.

Possible hazards include:

• Traffic striking the tower
• Castors moving from the kerb
• Insufficient leg adjustment
• Stabiliser feet extending into the road
• Restricted pedestrian access
• Unequal loading across the tower
• Underground drains close to the kerb

Work near roads and public areas may require barriers, permits, traffic management or a different access method.

For staircases and stepped areas, use a tower specifically designed and configured for stairwell work. Do not try to adapt a conventional freestanding tower using blocks, boxes or improvised supports.

Always Follow the Instruction Manual

The instruction manual determines how the tower must be assembled and used.

It should identify:

• The permitted tower configurations
• Maximum platform heights
• Required components
• Bracing patterns
• Stabiliser requirements
• Safe working loads
• Permitted adjustable-leg settings
• Assembly and dismantling methods
• Indoor and outdoor limitations
• Wind restrictions
• Inspection requirements

PASMA provides access to manufacturer-issued tower instruction manuals and emphasises that users should follow the instructions for their particular system.

Components from different manufacturers should not be combined unless compatibility has been formally established. Parts that look similar may have different dimensions, connection systems or structural capabilities.

Inspecting a Tower on Uneven Ground

A scaffold tower must be inspected after assembly and before first use by a competent person.

It should also be inspected at suitable intervals and whenever something occurs that could affect its safety or stability. For construction work where a person could fall two metres or more, HSE guidance states that inspection is required after assembly and then every seven days.

When the tower is being used outside or on challenging ground, additional checks may be needed following:

• Heavy rain
• Strong winds
• Ground disturbance
• Vehicle movement nearby
• Impact with the tower
• Repositioning
• Alteration
• Changes in load
• Signs of sinking or movement

The inspection should include the ground beneath every castor, base plate and stabiliser.

Stop using the tower immediately if:

• A leg has sunk
• A castor has moved
• The tower is leaning
• A stabiliser has become loose
• The ground has softened
• A component is damaged
• The tower no longer feels stable

The problem must be corrected before anyone climbs the tower again.

Should a Scaffold Tower Be Moved Over Uneven Ground?

A mobile tower should only be moved in accordance with the manufacturer’s instructions.

Before moving it:

• Remove all people
• Remove or secure tools and materials
• Check the intended route
• Look for slopes, holes, kerbs and obstructions
• Check for overhead hazards
• Release the castor brakes
• Apply force close to the base
• Move it slowly and under control
• Relock all castors after repositioning
• Relevel and reinspect the tower

Never move a tower while someone remains on the platform.

If the ground is too rough or uneven for the tower to roll smoothly, dismantling and rebuilding it in the new location is generally safer than attempting to force it across the surface.

A Simple Ground-Condition Checklist

Before assembling a scaffold tower, ask:

• Is the ground firm?
• Is it sufficiently level?
• Can it support the complete loaded tower?
• Are all four castors or base plates fully supported?
• Can every stabiliser foot be positioned securely?
• Is the ground dry and unlikely to soften?
• Are there drains, voids or excavations nearby?
• Is the tower clear of traffic and pedestrians?
• Can the tower be made level within the leg-adjustment limit?
• Does the proposed configuration follow the manual?
• Has a competent person assessed the location?
• Can the tower remain stable for the full duration of the work?

When any of these questions cannot be answered confidently, do not proceed until the site or access method has been changed.

Final Advice

A scaffold tower may be used on slightly uneven ground when the difference can be safely corrected using the tower’s approved adjustable legs and when every part of the structure remains properly supported.

However, adjustable legs cannot make soft, unstable or excessively sloping ground suitable. They are intended to level the tower, not to add working height or compensate for poor site preparation.

Always ensure that:

• The ground is firm and capable of carrying the load
• The tower is level and vertical
• Castors are locked before use
• Stabilisers are correctly fitted and supported
• No bricks, blocks or improvised packing are used
• The manufacturer’s instruction manual is followed
• The completed tower is inspected by a competent person

When there is any doubt about the ground conditions, stop and seek advice from the tower manufacturer, supplier or a competent access specialist. Choosing a different access solution is always preferable to using a scaffold tower in an unsafe configuration.