Bolt-On vs. Cast-In Balconies: Key Differences & Best Use Cases

In modern construction, selecting the right balcony system is a critical decision. This choice directly impacts both your project timeline and your budget. As developers increasingly prioritize fast, cost-effective solutions, architects and contractors must decide between two primary methods: Bolt-on and Cast-in balconies.

Understanding the structural and logistical differences between these systems helps you select the most efficient solution, whether you are managing a new build or a complex high-rise retrofit.

At a Glance: Comparison Table

A technical comparison of Bolt-On and Cast-In balcony systems based on manufacturing, installation speed, structure, retrofit suitability, and fire compliance.

What is a Bolt-On Balcony?

Manufacturers build bolt-on balconies in a controlled factory environment before transporting them to the site. Once they arrive, installers secure them to the building frame via precision brackets. Furthermore, because the main structure is already complete, this method streamlines the final stages of construction.

• The Modular Advantage: Factory production ensures higher precision and stricter quality control.

• Minimal Disruption: Consequently, other trades can continue working on the building envelope uninterrupted.

• Lightweight Design: Engineers typically utilize aluminium to achieve a high strength-to-weight ratio.

What is a Cast-In Balcony?

A cast-in system integrates the balcony directly into the building’s concrete slab. Contractors embed the balcony components during the pouring process, making it a permanent part of the building’s core structure.

• Structural Integration: This method creates a seamless, rigid connection to the slab.

• Durability: While these systems are highly sound, they remain extremely difficult to modify once the concrete sets.

• Logistical Challenges: In contrast to modular systems, cast-in balconies require extensive on-site coordination, formwork, and curing time.

Key Differences:

1. Installation Speed

Cast-in systems demand precise coordination with concrete pours; consequently, any delay in curing can stall the entire project schedule. Conversely, bolt-on systems arrive ready for immediate attachment. Once you prepare the structural frame, teams can install multiple units in a single day, drastically reducing on-site labor costs.

2. Structural Impact & Flexibility

Because cast-in balconies are permanent, post-construction modifications are often expensive and complex. However, bolt-on balconies offer significantly more design flexibility. They distribute the load through bracket supports, which often allows you to design a lighter overall building structure.

3. Fire & Building Regs Compliance

With the introduction of the Building Safety Act, compliance is now the top priority for specifiers.

• Part B (Fire Safety): Bolt-on units simplify certification because factories use pre-tested, non-combustible materials like A2-rated aluminium.

• Thermal Bridging: Additionally, installers can include thermal breaks in bolt-on systems to minimize heat loss, helping you meet NHBC and RIBA energy standards.

Which System Should You Choose?

Opt for Bolt-On Balconies When:

• Managing High-Rise Developments: Where reducing structural weight and increasing installation speed are vital.

• Executing Retrofit Projects: These systems are ideal for upgrading older residential blocks with minimal disruption to residents.

• Prioritizing Quality: Modular construction ensures consistent, factory-grade finishes every time.

Opt for Cast-In Balconies When:

• Building Low-Rise Structures: Where traditional on-site construction methods are already in place.

• Designing for Specific Aesthetics: When the architectural vision requires a continuous, monolithic concrete slab.

Why Choose Neaco’s Balcony Systems?

Neaco provides high-performance balcony solutions that exceed the strictest UK fire safety and structural requirements. Whether you require a bolt-on cantilever balcony or a specialized integrated system, our products offer:

• A2-Rated Compliance: Ensuring your project meets the latest non-combustible standards.

• Rapid Installation: Helping you stay ahead of your construction schedule.

• 50 Years of Expertise: We remain a trusted partner for architects across iconic UK developments.

Ready to specify your system? Contact our technical team for custom specifications and BIM/CAD downloads.