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CLT panels for timber construction
CLT technology

CLT panels for timber construction

CLT panels enable solid timber load-bearing structures, hybrid solutions and multi-storey timber buildings — with precise factory production and ZTC experience.

ZTC experience and production facts

35+

years of experience

400+

completed projects

14

European countries

±1 mm

CNC precision

When CLT panels are appropriate

CLT panels are a solid timber structural element that must be reviewed together with architecture, loads and energy performance. ZTC helps compare CLT with timber frame panels and certified structures. See also CLT houses and completed projects.

CLT panel technical parameters

Indicative technical limits and capabilities to consider during design and production planning.

Maximum panel size

13,800 × 3,100 mm

Building height

up to 8 storeys

Fire resistance

up to EI 120

Acoustics

up to Rw 65 dB

CLT applications and typical scenarios

CLT may suit

  • Solid timber load-bearing structures and multi-storey timber buildings.
  • Hybrid solutions where CLT is used in specific zones.
  • Projects with exposed timber surfaces and higher structural demands.

Timber frame is often practical

  • Private homes up to around 3 storeys where timber frame is cost-effective.
  • When the priority is an insulated panel system with factory preparation.
  • When flexible scope and fast panel assembly matter most.

Brief CLT vs timber frame comparison

This comparison is indicative. Architecture, loads, energy performance and scope must be reviewed for the specific project.

CLTTimber frame
Structure typeSolid timber panels as the load-bearing structure.Frame system with an insulated panel solution.
HeightMore often multi-storey and hybrid projects.More often private homes up to around 3 storeys.
ProductionPanels are factory-made with ±1 mm CNC precision.Panels are factory-made with ±1 mm CNC precision.
AssemblyOn-site assembly typically around 3–5 days per floor.On-site assembly typically around 3–5 days per floor.

Frequently asked questions

Questions about CLT panels, technologies, comparisons and energy performance.

ZTC uses mineral wool, cellulose insulation and wood fibre insulation. The company has an industrial Isofloc system for blowing cellulose and wood fibre insulation.

ZTC uses mineral wool, cellulose insulation and wood fibre insulation. The company operates an industrial Isofloc system for blowing cellulose and wood fibre insulation.

Panels are connected with long screws or special timber connectors. A wind barrier is used externally, a vapour control layer internally, and membranes are carefully taped across the building.

Panels are connected with long screws or special timber connectors. A wind barrier is used externally and a vapour control layer internally, with membranes carefully taped across the building.

Airborne sound insulation in timber houses can be very good, especially with cellulose or wood fibre. Impact sound in intermediate floors should be addressed with appropriate floor and ceiling solutions.

Airborne sound performance in timber houses can be very good. Impact sound in intermediate floors is addressed with appropriate floor and ceiling solutions.

For houses up to around 3 storeys, timber frame is often more economical. CLT may suit load-bearing structures, hybrid solutions or where exposed solid timber walls are desired.

For houses up to around 3 storeys, timber frame is often more economical. CLT may suit load-bearing structures, hybrid solutions or exposed solid timber walls.

ZTC manufactures and assembles houses itself, has experience since 1991, CE and ETA-21/0014 certification, Hundegger CNC precision of ±1 mm and an industrial insulation installation system.

ZTC manufactures and assembles houses itself. The company has experience since 1991, CE marking and ETA-21/0014, Hundegger CNC precision of ±1 mm and an industrial Isofloc insulation system.

Standard wall U-values are Comfort 0.167, Premium 0.136 and Lux 0.100 W/m²K.

The specified U-value depends on the complete wall build-up agreed for the project, including layers installed on site. Whole-building energy performance also depends on windows, junctions, airtightness and building services. Your design team coordinates these with the project’s energy assessor.

The n50 value describes building airtightness. In quality constructions it is possible to achieve n50 below 0.6, which is important for energy-efficient buildings.

The final EPC rating depends on the complete building specification and is determined by an accredited assessor for the project.

Insulation, windows, airtightness, heating, ventilation and renewables all affect the result. The project’s accredited assessor determines the final EPC rating from the full specification. ZTC panels can support the agreed energy target, but a structural package alone cannot guarantee an EPC rating. Your design team should coordinate the full specification with the assessor.

Energy calculations are prepared during the design stage, before the panel specifications are finalised, and updated for the completed building.

The client or design team appoints a qualified assessor. Agree responsibility early so the calculations can guide the insulation, windows, airtightness, heating, ventilation and any renewables before manufacture.

Yes. ZTC manufactures timber frame panels in Latvia and provides transport and on-site assembly in the UK according to the agreed project scope. Your local architect or project team is responsible for architectural drawings, approvals, foundations and site readiness. The offer sets out the exact division of work.

Are CLT panels suitable for your project?

Send your project information and ZTC will help review CLT, timber frame or a hybrid solution.