A Multi-Storey building in Peschiera del Garda made from CLT panels

Over the past two decades, the growing adoption of multi-storey timber buildings has highlighted the potential of timber as an alternative or complementary material to concrete and steel. 

The use of innovative materials, such as CLT (Cross Laminated Timber) panels, has delivered exceptional mechanical performance and design versatility, making engineered timber a preferred option in various contexts, including those with environmental constraints or stringent seismic requirements.

The new multi-storey timber building under construction on the shores of Lake Garda, in Peschiera del Garda, Verona, provides a particularly compelling case study. This project incorporates hybrid construction solutions and optimised technical details, specifically designed to address the unique challenges of building with CLT panels. 

The challenges of multi-storey CLT buildings 

From an engineering perspective, designing and constructing a multi-storey timber building involves a thorough analysis of numerous structural factors. 
Firstly, resistance to horizontal forces (wind and earthquakes) requires the implementation of effective bracing systems, often consisting of CLT load-bearing walls and certified steel connectors. These ensure box-like structural behaviour and the proper redistribution of forces. 
 
Additionally, the building's height and the substantial loads it must bear make accurate dimensioning of the vertical support elements essential, along with the careful definition of technical details at the points where CLT encounters other materials. 

In the case of Peschiera del Garda, additional variables need to be considered due to the geographical and landscape context. The structure is situated near a lakeside, potentially presenting challenges in terms of humidity and visual impact.  

This created the need for an integrated design approach, simultaneously addressing the structural response of the timber building, architectural requirements and environmental sustainability criteria. 

The importance of preliminary design in CLT buildings 

The preliminary design phase plays a critical role in correctly dimensioning the elements of a multi-storey CLT building.  

Key tasks such as identifying loads, selecting the CLT panels, positioning load-bearing walls and defining connection solutions must be carried out in close coordination between the architectural engineer, structural engineer and director of works. For the project in Peschiera del Garda, the structure was meticulously planned by a team of professionals: 

• Architectural Engineer and Director of Architectural Works: Arch. Corradi Michael 

• Structural Engineer for Timber Works: Eng. Montresor Claudio 

• Director of Timber Structural Works: Eng. Bonadiman Devis 

The defining feature of this project lies in the deliberate decision to adopt certified and standardised systems, which streamlined the work during both the calculation and modelling phases as well as during construction.  
In particular, static issues related to the lateral load from the glass and steel railings were resolved through a collaborative analysis involving all parties, from the definition of construction details to the verification of overall stability. 

The advantage of fast construction in CLT 

One of the most appreciated aspects of construction using CLT panels is the speed of installation, facilitated by prefabricating panels in the factory and the ability to move them using lightweight site machinery. This rapid construction process offers numerous benefits: 

1. Shorter construction times: The timber structural elements arrive ready for installation, minimising on-site cutting and adjustments. This simplifies logistics and shortens the overall timeline. 

2. Lower indirect costs: A shorter construction period translates to fewer costs related to equipment rental, safety measures and labour, optimising the overall budget. 

3. Lower environmental impact: Less dust, noise and waste contribute to a reduced impact on the surrounding area, particularly in sensitive landscapes and tourist areas like the shores of Lake Garda. 

In the specific case of Peschiera del Garda, the aim of constructing a multi-storey timber building on a tight schedule allowed the project to be planned for completion by spring 2025, minimising disruption in an area of high landscape and cultural significance. 

The Peschiera del Garda case study: collaboration and construction details for a multi-storey CLT building 

The timber building owned by Zaimi Laura features a multi-storey structure with load-bearing walls and most floors constructed using CLT panels.  

Part of the fourth floor will also be built with glulam, a design choice that optimises structural performance while fully leveraging the mechanical properties of different types of timber products. This combination of CLT and glulam showcases the construction flexibility offered by timber, particularly in complex, large-scale projects. 

The Peschiera del Garda project demonstrates how integrating multidisciplinary expertise and involving specialised companies can lead to exceptional results. 

CG Edilservice SRL and Wood Technology SRL were responsible for supplying and installing the CLT panels, as well as providing all "turnkey" services for the timber construction. 
Rothoblaas supplied metal connectors, airtight tapes and inter-floor acoustic profiles, essential components in ensuring the structure’s sturdiness, performance and long-term durability. 

The collaboration between these companies enabled the in-house development of individual construction details, drawing on the expertise of specialised personnel in both structural calculations and on-site installation.  

The adoption of a "golden rule" – “every step must be simultaneously analysed, designed, engineered and executed” – promoted a disciplined approach, ensuring superior quality control and adherence to project timelines.

Performance, reliability and attention to detail: 
multi-storey timber buildings pave the way for a greener future. 

The proper selection of metal connectors, anchor systems and acoustic solutions plays a crucial role in the performance of a multi-storey timber building. In this project, Rothoblaas provided tested and certified devices specifically designed to withstand loads and minimise acoustic bridging between floors. The use of standardised elements simplified the design process and enhanced on-site efficiency, minimising the risk of assembly errors. 

A critical factor for the stability of the structure is the proper sizing of angle brackets and connectors to ensure shear resistance.  

Products like those in the TITAN range by Rothoblaas, including TITAN N, are designed to deliver high performance in terms of stiffness and strength, ensuring optimal load transfer between the CLT elements.   

Beyond the structural aspects, energy performance and indoor comfort are essential considerations. To this end, proper taping and airtightness are crucial in preventing infiltration, thermal dispersion and premature degradation of the timber material. Solutions such as FLEXI BAND by Rothoblaas, available here, provide excellent elasticity and adhesion, perfectly adapting to joints and ensuring the continuity of the building envelope. This approach ensures that the building maintains its energy efficiency and living comfort standards over time. 

This balance between structural effectiveness and construction efficiency is crucial in ensuring the competitiveness of CLT compared to traditional building systems. 

Inter-floor acoustics and the use of XYLOFON 

Worthy of mention is the decision to invest in acoustic insulation between floors, a critical factor in ensuring residential comfort. 
 
With this in mind, XYLOFON by Rothoblaas was selected, a resilient profile specifically designed to reduce impact noise transmission and improve sound absorption. Thanks to its elasticity and material composition, XYLOFON effectively absorbs vibrations caused by impact sound or furniture movement, significantly improving the overall acoustic performance of the building. In the Peschiera del Garda project, this choice complements other measures implemented in terms of connections and insulation materials, ensuring a more comfortable living environment.

Reaching new heights: hybridisation and future prospects for multi-story CLT buildings 

CLT construction is evolving along two main paths. On one hand, there is a move towards hybridisation with other materials, such as steel and concrete, to combine the strengths of each one. This hybrid solution is often used in lower floors (for example, reinforced concrete podiums) or vertical cores (stairwells and lift shafts), where stresses tend to be most severe.  
On the other hand, there is a growing focus on standardisation and modularity, aimed at creating tall buildings using mass-produced timber elements. 

These trends open up exciting opportunities for the increased adoption of timber buildings on an international scale. Ongoing research into cutting-edge solutions, combined with the development of more flexible regulations and the growing availability of certified products, is paving the way for the construction of increasingly taller multi-storey buildings.  
Projects such as Mjøstårnet in Norway or TREET in Sweden demonstrate how timber can reach for the realm of skyscrapers, thanks to established engineering expertise and a specialised supply chain capable of ensuring construction quality. 

In Italy, the CLT multi-storey project in Peschiera del Garda stands as a striking example of the structural possibilities offered by this material. An integrated approach, collaboration among professionals and the selection of certified systems provide the foundation for overcoming the technical challenges associated with great heights and specific environmental conditions.  

Our catalogue, “Plates and connectors for timber”, available for download here, is based on this same promise.  

Architectural Engineer and Director of Architectural Works: Arch. Corradi Michael   

Structural Engineer for Timber Works: Eng. Montresor Claudio   

Director of Timber Structural Works: Eng. Bonadiman Devis   

CLT panels: CG Edilservice SRL and Wood Technology SRL   

Owner: Zaimi Laura 

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