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Stepoc Blocks: Complete Guide

Stepoc Blocks: Complete Guide to Retaining Walls, Basements, Flood Defences, Design and Prices

Executive Summary

The Stepoc block guide: Stepoc blocks are a reinforced concrete walling system widely used for retaining walls, basements, flood defence structures, and other load-bearing applications. Their dry-stack construction and concrete-filled core allow for faster installation compared to traditional reinforced concrete walls while maintaining high structural strength.

Key benefits include:

• Reduced need for temporary formwork
• Faster construction and labour savings
• High load-bearing capacity when reinforced
• Suitable for restricted-access sites
• Flexible design for a wide range of structural applications

Typical uses:

• Retaining walls
• Basements
• Flood defence and water-retaining walls
• Industrial and agricultural buildings

What Are Stepoc Blocks?

Stepoc blocks are specially designed hollow concrete blocks that create strong reinforced concrete walls without the need for traditional timber or steel formwork.

The blocks are stacked dry, reinforced with steel bars and then filled with concrete, creating a solid structural wall. They are widely used for retaining walls, basements, flood defence structures and other projects where strength and durability are essential.

Because the blocks act as permanent formwork, construction is often faster and more economical than conventional reinforced concrete, making Stepoc a popular choice for engineers, contractors and developers across the UK.

How Does a Stepoc Retaining Wall Work?

A Stepoc retaining wall works by combining concrete blocks, reinforcing steel and structural concrete into one reinforced structure.

The blocks are laid onto a reinforced foundation before steel reinforcement is installed vertically and horizontally through the hollow cores. Once everything is in position, the wall is filled with concrete to create a solid reinforced concrete core capable of resisting the pressure from the retained ground.

To ensure long-term performance, the wall also requires a correctly designed foundation and an effective drainage system to prevent water pressure building up behind the structure.

Stepoc Flood Defence Walls

Stepoc blocks are an excellent choice for flood defence walls because they form a strong, reinforced-concrete barrier capable of withstanding high water pressure.

Once reinforced and filled with concrete, the wall becomes a robust structure suitable for protecting homes, commercial buildings, industrial sites and critical infrastructure from flooding.

Every flood defence wall should be individually designed to suit the site, taking into account expected flood levels, hydrostatic pressure, foundation design and waterproofing requirements. When properly engineered and constructed, Stepoc walls provide a durable, low-maintenance solution that can protect properties for decades. Learn more about Stepoc flood defence walls.

Stepoc Basement Construction

Stepoc blocks are widely used in basement construction because they provide a quick and efficient way of building reinforced concrete basement walls.

After the blocks have been stacked and reinforced, they are filled with concrete to create a strong structural wall capable of resisting both soil and groundwater pressures.

Compared with traditional shuttered concrete walls, Stepoc can reduce construction time while maintaining excellent structural performance.

Every basement should be designed by a structural engineer and include an appropriate waterproofing system, drainage strategy and reinforced foundation to ensure the structure remains dry, safe and durable throughout its design life. Learn more about Stepoc Basement Construction.

Stepoc Retaining Wall Design

Every Stepoc retaining wall should be designed by a qualified structural engineer.

The design is based on much more than simply deciding how high the wall will be. Factors such as:

• Soil conditions
• Retained height
• Surcharge loads and
• Foundation bearing capacity

From these calculations, the engineer determines the correct block width, reinforcement, concrete strength and foundation dimensions.

A properly designed Stepoc retaining wall will safely resist sliding, overturning and structural bending while providing a durable and cost-effective retaining wall solution. More on retaining wall structural design.

Stepoc 200 Block Installation Guide

Stepoc 200 blocks are designed to accommodate a single layer of reinforcement and are laid in a half-bond pattern. The first course should always be laid on a mortar bed to ensure the wall starts level and accurately aligned.

The wall should be designed in accordance with the relevant structural design standards, ensuring the reinforcement is positioned exactly as specified by the structural engineer.

Construction Guidance

• Construct all corners and end details first before building the main wall.
• Position any cut blocks towards the centre of the wall wherever possible.
• Provide movement joints at maximum 20-metre centres, using end detail blocks to terminate and restart the wall.
• Maintain a minimum 40mm concrete cover to all vertical reinforcement.

Concrete Specification

The concrete infill should comply with the structural engineer’s specification and should be no less than:

• Concrete strength: C32/40
• Workability: Minimum 150mm slump (S4)
• Maximum aggregate size: 10mm

Maximum Concrete Pour Height

To maintain the stability of the dry-stacked blocks during construction, concrete should be placed in controlled lifts.

• Maximum pour height: 8 courses (approximately 1.8 metres)

Stepoc 256 Block Installation Guide

 

Stepoc 256 blocks have a modified internal web design that allows two layers of reinforcement to be installed. However, for most retaining wall applications, a single layer of reinforcement is usually sufficient, depending on the structural design.

All calculations should be completed using the correct reinforcement positions and in accordance with the relevant structural design standards.

Construction Guidance

• Construct corner and end details first before building the remaining wall.
• Locate any cut blocks towards the centre of the wall.
• Install movement joints at maximum 20-metre centres, using end detail blocks to finish and restart the wall.
• Reinforcement shown on standard details is at the minimum practical spacing. The structural engineer may increase the spacing where appropriate, provided centres remain multiples of 133mm.
• Maintain a minimum 40mm concrete cover to all vertical reinforcement.

Concrete Specification

Concrete should comply with the structural engineer’s specification and should be no less than:

• Concrete strength: C32/40
• Workability: Minimum 150mm slump (S4)
• Maximum aggregate size: 10mm

Maximum Concrete Pour Height

Concrete should be placed in controlled lifts to minimise pressure on the dry-stacked blocks.

• Maximum pour height: 10 courses (approximately 2.25 metres)

Stepoc 325 Block Installation Guide

Stepoc 325 blocks are designed to accommodate two layers of reinforcement and are laid in a half-bond pattern. In most retaining wall applications, a single layer of reinforcement is typically installed on the retained face, although the final reinforcement arrangement should always follow the structural engineer’s design.

All structural calculations should use the correct reinforcement positions and comply with the relevant design standards. The characteristic compressive strength of the masonry is fk = 18 N/mm².

Construction Guidance

• Build all corner and end details first before constructing the main wall.
• Position any cut blocks towards the centre of the wall.
• During construction, temporarily prop free-standing corners before placing concrete to improve stability.
• Install movement joints at maximum 20-metre centres, using end detail blocks to terminate and restart the wall.

Concrete Specification

Concrete should meet the structural engineer’s specification and should be no less than:

• Concrete strength: C35/40
• Workability: Minimum 150mm slump
• Maximum aggregate size: 10mm

The typical concrete infill requirement is approximately 0.19m³ of concrete per square metre of wall.

Maximum Concrete Pour Height

To prevent excessive pressure on the dry-stacked wall during construction:

• Maximum pour height: 10 courses (approximately 2.25 metres)

Stepoc Block Sizes and Dimensions

Stepoc blocks are manufactured in three standard widths, 200mm, 256mm and 325mm, to suit different structural applications. The 200mm and 256mm ranges are typically 400mm long by 225mm high, while the 325mm range uses a square 325mm by 325mm format.

Each range includes standard blocks together with matching end, corner and bonding units to maintain the correct bond throughout the wall. The size of Stepoc block required should always be determined by the structural design, taking into account the loads acting on the finished wall.

Stepoc Block Supply Prices and Stepoc Block Built Price per m²

Stepoc Block Prices

The cost of Stepoc blocks depends on the block size, supplier, quantity ordered and delivery location. As a guide, the blocks themselves typically cost between:

• 200mm blocks £70 – £85 per m2
• 256 mm blocks £75 -£90 per m2
• 325mm blocks £80 – £95 per m2

The price difference is between delivery prices from ex works to being delivered and merchant margins.

Stepoc Retaining Wall Prices

The prices for constructed retaining walls and flood defence wall ranges from £450 to £700 per m2 depending on the height of the wall, ground conditions and surcharge loads. The rates include excavation, building the wall, back drainage and filling behind the wall on completion.

Where to Buy Stepoc Blocks in the UK

Stepoc blocks are available across the UK through selected builders’ merchants, specialist retaining wall suppliers and authorised distributors of Ibstock’s Anderton products. Before placing an order, check that your structural drawings specify the correct block widths, end blocks and bonding units, as these all affect the final quantity required.

Most suppliers can arrange nationwide delivery and provide technical advice, quantity calculations and lead times. For larger projects, it is worth comparing quotations from several suppliers to secure the best combination of price, availability and delivery.

How to ORDER Stepoc Blocks

Retaining Wall Solutions are an Ibstock Merchant. We can give you prices and organise deliveries.

To give you a accurate price including special end and corner blocks we need to know:

• Wall length
• Wall Height
• Number of corners
• Number of ends
• If wall length is more than 20m number of expansion joint
• Full delivery address
• Your contact details

Complete the form below giving the above information within the notes section for a detailed quotation.

Delivery Options for Stepoc Blocks

Stepoc blocks can be delivered using a variety of vehicles depending on the size of the order and the access available on site. Smaller deliveries are typically made using:

• Rigid curtain side lorries – Standard loads
• Articulated vehicles – Large loads up to 27 ton
• Moffett vehicles – Where no site off loading is available

Before ordering, it is important to check access restrictions such as narrow roads, low bridges, overhead cables and turning space to ensure the delivery arrives safely and on schedule.

A moffett is a small forklift truck that is carried on the transport lorry to off load block pallets. Be aware delivery time may take longer as the moffett is in high demand, and is a little more expensive.

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