Sustainability, strength and speed – what is Cross-Laminated Timber (CLT) and why is it becoming increasingly more popular in modern construction?

Cross-Laminated Timber (CLT) has quickly become one of the most talked about topics in the construction industry. However, there’s often confusion and misinterpretations of its benefits, limitations and costs.

In this article, we will explain what CLT is, how it’s used in construction, its potential in future design, and its advantages and limitations.

What is CLT?

CLT is an engineered product constructed by stacking timber into perpendicular layers that are then pressed together and glued as shown in the image below:

Advantages

– Environmentally-friendly

Sustainably sourced timber is generally used by CLT manufacturers and timber building components have been found to use only half the energy to produce than their concrete counterparts.

– Lightweight

Being lightweight, CLT reduces load on foundations so there’s less need for materials with high embodied energy – such as concrete.

– Durable and Strong

CLT possesses great robustness and can be used in both wall and floor aspects of a structure.

– Modular construction

Constructed can be done off-site inside a factory before being transported to site. This enables construction to continue during periods of bad weather.

– Fast on-site construction

Because CLT panels can be constructed off-site, it enables quicker on-site construction ultimately reducing the overall construction timeline.

Limitations

– Fire

The biggest concern with CLT is its vulnerability to fire. However, in the event of a fire, the outer laminated layer melts to form a barrier resistant to fire for 30-40mins.

– Requires accurately set out groundworks

Due to CLT panels being constructed in a factory, there is no room for error when it comes to the design and layout of groundworks.

– Requires external cladding

CLT is wood, so it’s not fully weatherproof. To achieve a weatherproof solution, external cladding or render is required.

How CLT is used in construction

Cross-Laminated Timber (CLT) is typically manufactured in panels. The size of the panels can vary; however, the width is determined by the scope of the manufacturing machinery and the length is determined by the method of transportation to site. Once manufactured, the CLT panels are then transported and erected on-site.

Traditionally, on-site construction is affected by variations in weather – for example, storms, heavy rain and strong wind – and has a greater environmental impact. CLT’s popularity primarily comes from it’s low-environmental impact and ability to continue production during bad weather.

The future of construction and CLT design

Around the world CLT is currently being used for a variety of projects – from small residential houses, to commercial and industrial towers of up to ten storeys. CLT is becoming increasingly more popular due to the shorter construction timeframes achievable and its off-site construction capabilities.

The future of CLT will most likely see a further innovation push, enabling quicker production, increased durability and easier transportation.

Is CLT right for my project?

Every project is different and will have different implications and design requirements. Check BRANZ for the latest information and reports on CLT.

Contact us today to see if CLT is a right fit for your project!