Cross-Laminated Timber – CLT

Cross-laminated Timber Fire Protection

Keeping cross-laminated timber protected

CLT has some advantages as a building material, including:

  • Design flexibility – CLT has many applications. It can be used in walls, roofs or ceilings. The thickness of the panels can easily be increased by adding more layers and the length of the panels can be increased by joining panels together.
  • Eco-friendly – CLT is a renewable, green and sustainable material since it is made out of wood. It can sequester carbon, but differences in forest management practices translate into variations in the amount of carbon sequestered.
  • Prefabrication – Floors or walls made from CLT can be fully manufactured before reaching the job site, which decreases lead times and could potentially lower overall construction costs.
  • Thermal insulation – Being made out of multiple layers of wood, the thermal insulation of CLT can be high depending on the thickness of the panel.
  • CLT is a relatively light building material – Foundations do not need to be as large and the machinery required on-site are smaller than those needed to lift heavier buildings materials. These aspects also provide the additional capacity to erect CLT buildings on sites that might otherwise be incapable of supporting heavier projects and eases infilling projects where construction is especially tight or difficult to access due to the preexisting buildings around the site.

If you have a project where you need to protect CLT.

Please contact our team on 0330 094 9099 or

CLT Cross Laminated Timber ATOL
Cross Laminated Timber

CLT Fire Protection

One of the major advantages of Cross Laminated Timber is its inherent fire resistance. CLT can be designed to accommodate substantial fire resistance and unlike steel remains structurally stable when subjected to high temperatures. CLT panels can be produced with fire resistances of 30, 60 and 90 minutes.

It’s easy to see why any form of timber construction can pick-up a reputation for fire risk, but for solid wood and Cross Laminated Timber, performance in a fire is a long way from their timber frame cousins.

To understand how efficient CLT is in a fire, we should start with the understanding that fire resistance is the ability of a material to confine a fire or to continue to provide a structural function or both.

The measure of fire resistance is the time elapsed from the start of the fire up until the point where the material fails to function. Typically resistance is expressed in minutes eg FR 30, 45, 60 or 120.

CLT’s fire resistance is provided through ‘charring’. As the face of the timber panel is exposed to a fire that ramps up to a temperature in excess of 400 degrees C, the surface of the timber ignites and burns at a steady rate. As the timber burns it loses its strength and becomes a black layer of ‘char’. The char becomes an insulating layer preventing an excessive rise in temperature within the unburnt core of the panel. It is this unaffected core which continues to function for the period of the fire resistance.

To achieve the designed fire resistance period there must be sufficient virgin solid timber remaining behind the char layer to sustain the loads applied. Therefore each CLT panel within the building must be designed for the fire resistance period and the specific loadings applied to that panel.

Fire resistance testing of CLT panels is to ISO 834 – the same standard used for doorsets which most of us are familiar with.

Our Services

We Do More Than Just
Timber Fire Protection

Concrete Fire Protection

Timber Glulam Fire Protection

Steel Intumescent Paint Protection

Commercial Construction

Fire Compartmentation

Fire Doors

Fire Resistant Wall Covering

Fire Barriers & Curtains

Let’s talk

Got a project?

We use cookies to give you the best experience. Cookie Policy