Cross laminated timber

What is Cross laminated timber (CLT)?

Cross laminated timber (CLT) consists of at least 3 and a maximum of 9 layers of spruce lamellae laid crosswise and glued together flat, generally with a symmetrical structure. These large solid wood panels are especially used for wall, ceiling or roof elements in modern timber construction. Gluing is done with PUR adhesive made by Purbond, a formaldehyde and solvent-free glue approved for the production of load-bearing wooden components.

The solid wood elements are precisely cut to size on the latest CNC timber framing machines according to plan. These produce large components with a thickness of 63 to 292 mm and formats up to 3 m x 15 m. The ready-for-assembly, trimmed elements are ultimately delivered to the construction site just-in-time.

Cross laminated timber (CLT) is suitable for load-bearing, bracing and non-load-bearing wall, ceiling and roof elements. The elements can be individually adapted to the demands made on structural design, fire protection, noise and thermal insulation and are therefore very well suited for public buildings such as schools, children’s nurseries, as well as for detached single-family homes and apartment blocks, office and commercial buildings. Cross laminated timber is used in utilisation classes 1 and 2, i.e. it may not be exposed to direct weathering. Our own in-house monitoring and external checks by accredited testing and monitoring bodies guarantee the high product quality.

Advantages of Cross laminated timber (CLT)


  • Highly load-bearing building material
  • Multiple crossed and glued lamellae offer excellent dimensional stability and size accuracy
  • Outstanding static properties
  • Enables modern architectural shapes due to loads being transferred in two directions


  • Technically approved construction product ETA-12/0327
  • Quality-controlled production, continuous internal and external checks
  • Industrially prefabricated construction elements thanks to CNC timber framing according to plan
  • Ideal building material for adding storeys due to its specific weight


  • High dimensional accuracy due to CNC timber framing
  • Planning freedom and free floor plans
  • No restriction due to grid pattern
  • No limits on individual forms of expression in modern timber construction architecture


  • Ecological building material made of renewable raw material
  • Durable construction method that retains its value
  • Building product that stores CO2, hence climate-neutral construction
  • Highly efficient production with low primary energy demand

Building physics

  • Outstanding constructional properties
  • Very good thermal insulation and heat protection
  • Passive house and low-energy house standards can be optimally achieved
  • Healthy and comfortable indoor climate, optimal heat storage capacity and humidity regulation
  • Breathable wall elements, no vapour/moisture barrier necessary
  • Recommended in terms of building biology
  • The flat design with sealed surface layers achieves considerable benefits in relation to the thermal insulation, moisture, fire and sound protection, as airflows in the area of the component are prevented


  • Ready-to-assemble trimmed components are delivered directly to the construction site
  • Large format components minimise the assembly time and hence the construction costs
  • Dry construction method, hence rapid erection and soon ready for occupancy
  • Assembly-friendly

Cross laminated timber (CLT) panel structure

Dimension table
BSP panel structure type DL ceiling and roof element

Dimension table BSP panel structure type DL ceiling and roof elementBSP panel structure type DL ceiling and roof element" >

Dimension table BSP panel structure type DL fiber-parallel cover layers for ceiling and roof

Dimension table<br alt=BSP panel structure type DL fiber-parallel cover layers for ceiling and roof" title="Dimension table BSP panel structure type DL fiber-parallel cover layers for ceiling and roof" >

Dimension table
BSP panel structure type DQ for wall elements

Table BSP panel structure type DQ for wall elementsBSP panel structure type DQ for wall elements" >

Brochure: Cross laminated timber (CLT)

Would you like to find out more about our Cross laminated timber (CLT)?
You can find out everything about our cross laminated timber in our information brochure:

  • Advantages of cross laminated timber
  • Panel structure & surfaces
  • Ecology & building physics
  • Technical data
  • Planning
  • Timber framing and assembly
  • etc.

Cross laminated timber CLT

Cross laminated timber (CLT) surfaces

Cross laminated timber (CLT) statics & building physics

Statics TYPE L ceiling element

Statics TYPE L ceiling element

Statics TYPE W wall element

Statics TYPE W wall element

Building physics

Sound insulation

The sound insulation of the solid components is based on their mass and bending resistance. In order to achieve good sound insulation values even for components that separate living rooms belonging to different people from each other, double-shell structures are primarily used. In this case, facing formwork that can serve simultaneously as an installation level are used if necessary. To achieve the required footstep sound insulation, constructional measures minimise the direct structure-borne sound transmission through the solid component by decoupling the noise emission on the upper side of the ceiling from the emitting surface on the lower side.

By combining screeds and footstep sound insulation mats on the top side with ceiling panelling on the underneath as well, very good footstep sound insulation is achieved for ED BSP | cross laminated timber elements. To minimise flanking transmissions in the connection area, elastic bearings are used for the ceiling elements and special fasteners, which helps to improve sound insulation between the utilisation units even further. Last but not least, the constructional separation of components (e.g. preventing continuous walls and ceilings) also contributes to sound insulation.

Sound insulation example

Sound insulation example

Thermal insulation

Nowadays, rising energy costs and statutory energy savings provisions (ENEV) demand building materials with very good thermal insulation. With its low thermal conductivity (λ=0.13 W/mK) and high specific thermal capacity (c~2.10 kJ/kgK), cross laminated timber ideally meets these requirements.

The heat transmission coefficient (U value) provides information about the thermal insulation of the overall wall structure when there are different temperatures on both sides of the wall.

Example of external wall structure (from inside to outside):

Example of external wall structure

The high thermal capacity of ED BSP | cross laminated timber also ensures good summer heat protection. The solid ED BSP | cross laminated timber wall, ceiling and roof elements heat up only slowly and can store a lot of heat, so the temperature increase only becomes noticeable in the interior after 10 to 14 hours (phase shift).

ED BSP | cross laminated timber can be combined with the most varied insulating materials (wooden, mineral, or glass fibre insulating materials, cellulose, hemp, thermal insulation composite system). to achieve insulation values all the way to the passive house standard. Additionally arranged room-side installation levels lead to a further improvement of the insulation standard. Here, attention must be paid to execution without thermal bridges and airtight connections.

Wood protection

Cross laminated timber elements may only be used in utilisation classes 1 and 2 in accordance with DIN EN 1995-1-1. Thus, the application areas are fully enclosed and heated structures or covered open structures, for example, whose components are not exposed to the weather. Preventive constructional measures and professional, detailed execution usually make chemical wood protection in utilisation classes 1 and 2 unnecessary.


Solid ED BSP | cross laminated timber panels are airtight from the 5-layer structure upwards. The component connections (butt joints, window, door and base connections as well as penetrations, etc.) must be professionally sealed with compression tapes and the suitable adhesive tapes. to create flow-tight building shells that minimise heat loss and optimise sound insulation.

Fire protection

In case of fire, wood has the property of forming a protective carbon layer. This reduces the supply of oxygen and heat, thereby significantly delaying combustion. The fire behaviour of wood can be calculated. According to their European technical approval, cross laminated timber elements are assigned to building material class B2 acc. to DIN 4102-1 or fire behaviour class D-s2,d0 acc. to EN 13501-1. With an increasing wall thickness or number of layers, the fire resistance rating of the cross-section can be increased, meaning that a fire resistance period of 60 or 90 minutes is even possible.

By means of the corresponding panelling (e.g. fire protection panel made of plaster) or surface coatings, it is possible to achieve flame-resistant component surfaces. Component connections require particular attention from a fire safety point of view. If demands are made on the fire resistance of coated or uncoated ED BSP| cross laminated timber elements, proof of the necessary component properties takes place as part of the structural analysis by the structural engineer. This is done with the mathematical proof for each component in accordance with DIN EN 1995-1-2 taking the combustion rate into account.

Moisture protection

ED BSP | cross laminated timber is a breathable building material with vapour barrier properties. Depending on moisture content, its water vapour diffusion resistance coefficient μ lies between 20 and 50. When creating a breathable external insulation and façade, films that act as a vapour or moisture barrier are unnecessary.

The property of ED BSP | cross laminated timber to absorb indoor moisture without damage (sorption property) promotes a comfortable and balanced indoor climate.

Dimensioning programme

Dimensioning programme for BSP

The free-of-charge dimensioning programme for ED-BSP cross laminated timber supports you when planning your cross laminated timber projects. This programme can be used to dimension the cross laminated timber elements according to static loading. The basis for the CLT designer is the Eurocode 5 with the national appendices for Germany and Austria as well as the Tymoshenko method and the research results of the Technical University of Graz.

Simply use the form below to register so you can immediately gain access to the CLT designer via email. The programme requires the installation of Java SE Runtime Environment (JRE 8).

Register now

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Cross laminated timber (CLT) planning & timber framing

3D CAD planning

Planning and work preparation

The planning and work preparation is carried out by our own employees at the company. Since they worked previously as carpenters, they also have the professional knowledge for assembly work.

  • Professional planning
  • Individual project development by having direct contact to a designated contact person, short information channels
  • Designing with Dietrich’s timber construction software
  • Optimal and practical detailed solutions, technical project advice
  • Basis for 3D CAD planning may be plans in paper form and pdf files, or for direct data import: dwg, dxf, sat and ifc files
  • Structural pre-calculations with the DC-Statik design software
  • Visualisation in the planning phase, 3D tour through planned building, 3D pdf
  • Flexible scheduling

CNC timber framing

CNC timber framing according to planning file in our portal processing centres. Computer-aided manufacturing (CAM) with high precision according to 3D CAD planning. Individual panel dimensions, no standard widths.

  • Format cut
  • Window and door openings
  • Recesses
  • Rebates, jaggings and milled cut-outs for the element joint
  • Bevel cuts
  • Round cuts, round milling
  • Drill holes
  • Milled cut-outs for electrical installations
  • Cut-outs for ceiling beams
  • Special timber framing

Cross laminated timber (CLT) - Assembly

Assembling cross laminated timber

The ED BSP | structural elements cut to size according to plan are delivered at the construction site on the requested date and according to the assembly sequence, and a construction crane is used to unload and move them. An experienced timber construction company or carpentry firm takes care of the professional screwing of the external and internal wall elements and ceilings according to the information supplied by the structural engineer. As early as on the 2nd day, the building of a detached house can be completed with the roof. The exterior insulation is ideally done with wood fibre insulation boards. Whether plaster base boards and plaster or timber formwork is used, the builder can design the façade as he wishes. For the interior construction, plasterboard or gypsum fibreboards are recommended, but the timber surface can also remain visible. There are no limits externally or internally to architectural creativity.

  • ED BSP | structural elements must be protected against the weather, moisture and dirt on the construction site with suitable means
  • The large format components enable a fast assembly and ensure the building is well braced
  • Component connections are facilitated by guiding grooves in inner walls, interlocking joints in external walls and damper cover strips in ceilings and roofs
  • The component connections must be sealed according to recognised engineering standards.
  • ED BSP | cross laminated timber is breathable. If the insulation and façade are also designed to be breathable, films acting as a vapour barrier are not necessary

Are you interested in Cross laminated timber (CLT)?

Eugen Decker is your cross laminated timber manufacturer in Hunsrück / Germany.
We look forward to hearing from you!