ARE UHPC BALCONIES SUITABLE FOR CLT BUILDINGS?

Why Ultra High Performance Concrete balconies are quickly becoming a go-to solution

THE MATERIAL CHOICE MATTERS

As Cross-Laminated Timber (CLT) becomes increasingly popular in modern construction, the practical structural challenges that come with it are becoming more apparent. Ultra High Performance Concrete (UHPC) balconies are emerging as a strong and reliable solution for CLT projects. With lower weight, high strength, long service life and great design flexibility, UHPC balconies effectively solve many of the typical challenges of incorporating balcony elements into lightweight timber structures.

WHY USE UHPC BALCONIES IN TIMBER CONSTRUCTION?

CLT is becoming more widespread thanks to its low weight and renewable qualities. But one of the key challenges in CLT projects is adding elements such as balconies without overstressing the timber structure. This is where UHPC stands out.

Hi-Con’s UHPC balconies tackle CLT’s weak points directly. Their slim profiles reduce weight and structural impact on CLT panels, simplifying connection design and reducing thermal bridging. Prefabricated off-site, these balconies arrive ready to install, minimizing on-site complexity and risk.

Because UHPC offers exceptional strength and durability, these balconies are fire-safe without the need for fire paint and meet strength requirements without bulky or heavy construction. They also resist weather and wear for over a century with no structural maintenance needed. That means fewer callbacks, longer service life and a compelling LCA profile - perfect for CLT projects.

Additionally, the flexibility and shapeability of UHPC allow us to design elements that fit your project’s requirements and needs, with endless design possibilities and surface structures.

Read more about UHPC and its benefits here

The CLT project ‘Bøgehøj’ in Denmark, for which Hi-Con delivered slim balcony galleries.

BENEFITS OF UHPC BALCONIES FOR CLT PROJECTS

Weight reduction: UHPC elements are significantly lighter than regular-strength concrete, making them suitable for wood construction.

Compact dimensions: Balconies can be cast as thin as 6 cm, with 3 cm leading edges, reducing visual bulk and structural stress.

Long service life: Hi-Con’s UHPC has a documented lifespan of over 100 years with no structural maintenance.

Fire-resistant: UHPC meets high fire safety requirements without additional coatings or treatments.

Low maintenance: No corrosion protection is needed, unlike steel balconies.

Thermal compatibility: UHPC reduces the need for thermal breaks and insulation challenges.

The SAWA project in The Netherlands, for which Hi-Con delivered balconies. ©Ossip

HOW UHPC BALCONIES SUPPORT MODERN TIMBER ARCHITECTURE

The slim geometry and clean lines of UHPC balconies align well with the aesthetic goals of CLT projects. The material allows architects to realize floating designs, minimal detailing and high precision that would otherwise be difficult.

Additionally, UHPC’s flexibility in shape and surface finish opens up design possibilities without compromising durability or strength. This enables seamless architectural integration between timber facades and balcony elements.

PROVEN IN AWARD-WINNING PROJECTS

A clear example of UHPC’s compatibility with CLT construction is the SAWA building in Rotterdam, The Netherlands. The project, developed by Mei Architects, combines a CLT structure with UHPC balconies and access galleries supplied by Hi-Con. According to the architects, the use of UHPC aligned with their ambition to reduce raw material use and resulted in a design using around 50% less concrete compared to the other balcony solutions considered.

This combination helped SAWA meet its ambitious design and performance goals, while contributing to the building’s recognition as “the healthiest building in the Netherlands,” even before completion. The project has since completion won many awards and much recognition.

HOW TO GET THE BEST RESULTS WHEN USING UHPC FOR CLT STRUCTURES

To get the most out of this hybrid approach:

Engage early: Include Hi-Con in initial design discussions with your consultants. This gives our experts the opportunity to help find the best UHPC solution for your project and lets your team align on design from the start.
Focus on detailing: Specify balconies with integrated waterproofing, thermal breaks and clear interface tolerances. Prefab UHPC allows for consistent, reliable construction details.
Support sustainability goals: CLT’s low emissions combined with Hi-Con’s CRC i3 deliver strong environmental performance. Include them in your project’s LCA calculations and documentation.
Minimize site challenges: Precision off-site production cuts installation time, reduces weather exposure and ensures predictable delivery—even in complex urban sites.

LEARN MORE OR START A CONVERSATION

Curious about whether UHPC balconies could strengthen your CLT project? We’re happy to walk you through the possibilities. Whether you need early design advice, technical clarification or a tailored balcony solution, our specialists are ready to support you from concept to installation.

Reach out for a conversation or explore how UHPC can help you design smarter, lighter and more durable timber buildings.

FAQS: UHPC AND TIMBER CONSTRUCTION

A: Yes. UHPC balconies from Hi-Con are designed to be light enough for CLT and timber buildings, making them a suitable and proven option.
A: UHPC is corrosion-resistant, requires no surface treatment, offers fire safety and provides a longer service life with less maintenance.
A: Hi-Con’s UHPC balconies are backed by EPDs and LCA documentation, enabling precise climate calculations in early-stage design.