Interlocking Concrete Blocks
Build faster with interlocking concrete blocks that adapt to your site
Engineered for speed, flexibility, and long-term performance
Interlocking concrete blocks are a modular, precast system that allows you to build strong, stable walls quickly – with no fixings or reinforcement. The nib-and-recess connection secures units together, ensuring walls are stable from day one, and layouts can be reconfigured as your project develops.
From material storage bays and earth retention to waste & recycling sites, our Allegro® ranges (1.5m, 1.6m, 1.8m) offer the ideal combination of block size, weight, and shape options to suit your design needs. Made from a durable C40 mix with a design life of up to 100 years, and featuring Class A1 fire performance – these precast interlocking blocks enable fast installation without compromising safety or durability.
Explore Our Interlocking Block Range
Each product in the Allegro® system is designed to address specific site challenges – whether it’s reducing handling, building taller walls, or creating complex multi-bay layouts.
Here’s an overview of what we offer:
Best for: Easier handling and fast installation
Our most compact Allegro® system. Lighter blocks and shorter lengths make this range ideal for low-level retaining walls and smaller storage bays.
- Sizes: 1,500 × 600 × 600mm, plus smaller blocks
- Weight: 1,270kg (full block)
- Concrete strength: C40
- Common applications: Low retaining walls, grain storage, fire separation
Best for: Heavy-duty use, taller walls, and complex layouts
The most versatile range in the system. Larger and heavier blocks, plus seven different block types, allow for stronger, higher, and more complex wall layouts.
- Sizes: 1,600 × 800 × 800mm, plus 6 additional block types
Weight: 2,460kg (full block)
Concrete strength: C40
Common applications: Waste & recycling, multi-bay storage, fire and blast walls
Best for: Long, continuous wall runs with fewer joints
Designed for longer walls with fewer lifts, the 1.8m range reduces installation time while maintaining strength and durability.
- Sizes: 1,800 × 600 × 600mm, plus part blocks
Weight: 1,522kg (full block)
Concrete strength: C40
Common applications: Large storage bays, earth retention, bulk recycling
Why Choose Our Interlocking Blocks?
Modular system – strong, stable walls with no fixings required
Multiple block sizes – part blocks for neat corners and tidy layouts
Fire resistant – Class A1 rated, with up to 120 minutes fire resistance (up to 4 hours with sealed joints)
Long design life – up to 100 years with unreinforced construction
Quick installation – fewer joints and faster build times
Versatile – suitable for storage, civils, waste management, and separation walls
Typical applications for Interlocking Concrete Blocks
Storage Bays
Earth Retaining Walls
Waste & Recycling
Handling & Installation
Delivered with cast-in lifting pins
Supplied with 2 × 2.5T spherical head lifting clutches
Offloaded and positioned with telehandler, forklift, or 360 excavator
Installed on a reinforced concrete slab or existing yard base
No fixings required – stability comes from the block weight and interlocking design
Jason Carroll - Essex Highways
Interlocking Block Comparison
| Range | Size (full block) | Weight | Block types | Best for |
|---|---|---|---|---|
| 1.5m Allegro® | 1,500 × 600 × 600mm | 1,270kg | 3 | Low walls, faster handling |
| 1.6m Allegro® | 1,600 × 800 × 800mm | 2,460kg | 7 | Heavy-duty, complex layouts |
| 1.8m Allegro® | 1,800 × 600 × 600mm | 1,522kg | 4 | Long, continuous wall runs |
Questions We Often Get Asked
No, the nib-and-recess design locks blocks securely without bolts or reinforcement.
The 1.5m is lighter and easier to handle, the 1.6m offers the widest range of block types for taller or more complex layouts, and the 1.8m is best for long, continuous wall runs.
Yes, interlocking concrete blocks are Class A1 non-combustible. They provide up to 120 minutes fire resistance, and up to 4 hours if joints are sealed with a fire-rated mastic.
Yes, their mass and fire performance make them suitable for fire separation or blast resistance applications.
Yes, blocks must be installed on a reinforced concrete slab or stable yard surface to ensure safety and performance.
Most orders can be delivered within 2–4 weeks, with nationwide coverage.
Yes, full technical information, datasheets, and CAD drawings are available to support your project.
