Key Points
- Perforated ribbed slabs (H-ONE) remove non-working concrete, cutting concrete and steel use and enabling longer spans.
- LCAs show up to ~40% lower embodied CO₂ versus conventional slabs, helped by fewer materials and integrated services (no suspended ceilings).
- Reusable ABS moulds and modular sizing reduce waste, speed casting, and adapt to many building types.
- Optional hybrids with CLT combine concrete’s compression with timber’s lightness; compatible with low-emission mixes.
- Biggest hurdles are code approval and habits; HOLEDECK targets both via engineering validation and standardised modules.
Full interview with HOLEDECK
1. HOLEDECK’s H-ONE system is touted as the most sustainable concrete structure in the world. Could you explain the key features of this system that contribute to its remarkable reduction in concrete and steel usage?
We base our approach on the "rule of the 4 optimals":
1/ The first goal is to comply with regulations, and what is the most demanding regulation? Fire safety. To ensure compartmentalisation, we dimension the compression layer based on the REI rating required for the building.
2/From there, we determine the maximum spacing between HOLEDECK beams that still allows this compression layer to function. This is our second optimal: minimising the number of secondary beams.
3/ The third optimal is intrinsic to the system itself: the H-ONE system stands out due to its innovative geometry, a perforated ribbed slab that removes non-essential concrete, minimising weight while maintaining structural performance.
4/ The fourth optimal is an optional enhancement: prestressing. H-ONE allows for increased spans by prestressing the ribs, reducing the concrete needed in intermediate vertical structures.
Other advantages also contribute to lowering the building's carbon footprint: by integrating the voids within the slab, H-ONE eliminates the need for additional suspended ceilings and raised floors, reducing both material use and total building height.
In short, these design optimisations enable up to a 40% reduction in concrete and steel consumption compared to conventional slabs.
2. You highlight a 40% reduction in CO2 emissions in the construction of buildings using HOLEDECK. How is this reduction measured, and what role do the design and materials play in achieving this sustainability milestone?
The reduction is measured through Life Cycle Assessments (LCAs) comparing HOLEDECK slabs with traditional slab systems. The H-ONE geometry reduces material volumes, directly lowering embodied carbon. Additionally, by reusing high-strength ABS moulds and integrating services within the structural system, we eliminate the need for secondary construction layers, further reducing emissions.
Design efficiency, particularly the optimisation of rib spacing and compression layer thickness, results in less cement and steel reinforcement, directly cutting the carbon footprint.
3. What specific structural efficiencies does HOLEDECK optimise to improve sustainability? How do these elements affect both performance and environmental impact?
H-ONE applies several structural optimisation strategies:
1/ Ribbed slab geometry: Enables longer spans using less material.
2/ Perforated voids: Decrease dead load and embodied carbon.
3/ Integrated services: Combine installations within the slab, eliminating suspended ceilings and increasing floor-to-floor height.
These structural improvements reduce construction costs, enhance architectural flexibility, and significantly lessen environmental impact.
4. In addition to reducing the weight and height of a building, HOLEDECK claims to improve sustainability in elements like enclosures and air conditioning. Could you elaborate on how this system leads to broader energy savings across the entire building infrastructure?
H-ONE embeds air ducts, electrical conduits, and even radiant heating/cooling systems within the slab itself. This integration eliminates the need for separate ceiling or floor systems, streamlining the thermal envelope and boosting energy performance.
Additionally, solutions like Plugdeck take advantage of these integrated voids to optimise HVAC distribution, reduce energy demand, and improve occupant comfort.
5. Given the versatility of the HOLEDECK system, how do you ensure that it remains adaptable to various construction types, from residential buildings to long-span projects? Could you walk us through how the system is tailored to different architectural requirements?
HOLEDECK offers three main modules with perforations (H-ONE with drop depths of 30, 45, and 68 cm) and three additional solid modules without perforations (H-FLAT with drop depths of 20, 25, and 50 cm, plus the previously mentioned sizes in the H-FLAT format), each tailored to different spans and load conditions.
Its modular nature enables customised rib spacing and mould sizing, making it adaptable to diverse architectural demands. Whether in low-rise residential developments or large-scale office buildings, H-ONE and H-FLAT systems can be configured to accommodate varying loads, ceiling heights, and service integration requirements.
6. How does the use of HOLEDECK’s customizable molds, which are reusable and made from high-strength ABS material, contribute to the overall sustainability of the construction process? Can you describe how these molds are integrated into the manufacturing and construction phases?
The moulds are lightweight and stackable, helping reduce shipping costs and transport emissions. They are ergonomic and designed for quick assembly and disassembly without fasteners. Made from high-strength ABS, the moulds are fully reusable, significantly reducing construction waste.
Their precision design ensures high-quality concrete casting and easy cleaning even after multiple uses, reducing resource consumption and maintaining excellent finish quality. All moulds are manufactured using recycled material and are 100% recyclable, forming a truly circular process.
7. The H-ONE system also integrates CLT (Cross-Laminated Timber) panels. How does the combination of concrete and wood improve structural efficiency, and what additional environmental benefits does this integration provide?
This integration is optional and varies depending on the design approach: from CLT to in-situ concrete, or even prefabricated slabs. Combining CLT panels with the H-ONE slab leverages the strengths of both materials: concrete’s compressive strength and timber’s tensile flexibility.
This hybrid approach reduces the required amount of concrete, lowering the structural carbon footprint. It also improves acoustic performance and indoor environmental quality, contributing to healthier, more sustainable buildings.
8. With the increasing demand for more sustainable construction practices, what are the biggest challenges HOLEDECK faces in scaling its system for large-scale projects, and how do you plan to overcome these obstacles?
The main challenge is shifting the traditional construction mindset and achieving regulatory approval for new slab geometries. Our strategy focuses on collaboration with engineers, architects, and certifying bodies to validate the H-ONE system’s performance and ease adoption across different markets.
We’re also investing in advanced digital modelling tools and expanding our modular product offerings to enhance scalability and economic viability.
9. Given that HOLEDECK claims to make a significant impact on CO2 reduction comparable to wood solutions, what do you see as the future of concrete in sustainable construction? Will systems like HOLEDECK push concrete towards becoming a more environmentally friendly material on a global scale?
We believe concrete will continue to play a central role in sustainable construction — but in smarter, lighter, and more integrated forms. Systems like HOLEDECK demonstrate how geometry and innovation can transform concrete into a low-impact, high-performance material, aligned with global carbon reduction targets.
Moreover, HOLEDECK is fully compatible with low-emission concrete mixes, which, combined with the system’s geometric efficiency, can further reduce the structure’s carbon emissions.
10. Looking at the future of sustainable construction, where do you see the next wave of innovation for materials like concrete? Do you foresee any breakthrough technologies or materials that could further improve the environmental impact of construction?
Beyond geometric and hybrid innovations, future developments will likely focus on: Low-carbon cements and alternative binders (such as LC3 or recycled aggregates); AI-driven design optimisation to reduce material usage; Circular economy strategies: Designing for disassembly and reuse.
Together with integrated structural systems like HOLEDECK, these advancements will pave the way for buildings that are not only low-carbon but also adaptable and regenerative.
