
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.
| CLT | Timber frame | |
|---|---|---|
| Structure type | Solid timber panels as the load-bearing structure. | Frame system with an insulated panel solution. |
| Height | More often multi-storey and hybrid projects. | More often private homes up to around 3 storeys. |
| Production | Panels are factory-made with ±1 mm CNC precision. | Panels are factory-made with ±1 mm CNC precision. |
| Assembly | On-site assembly typically around 3–5 days per floor. | On-site assembly typically around 3–5 days per floor. |
Related ZTC projects

Private residence
Modular House in Iceland
, Iceland
View project
Developer project
Industrial Facility Facade with CLT and Infill Panels
, Latvia
View project
Private residence
Material Harmony: The Interplay of Metal, Ash, and CLT
Nijmegen, the Netherlands
View project
Private residence
Authentic-Style Two-Storey House
Amsterdam, Netherlands
View project
Private residence
Modern Coastal House with Curved Timber Structures
Akershus, Norway
View project
Private residence
Sustainable Engineering: The CLT & SiOO:X Home
Leinster, Ireland
View projectRelated topics
- CLT housesCLT houses and hybrid timber structures reviewed together with ZTC factory-made timber solutions.
- Hybrid timber constructionHybrid timber construction for complex projects — combinations of timber frame, CLT, steel and concrete.
- Multi-storey timber buildingsTimber construction systems for multi-storey buildings — CLT up to 8 storeys, hybrid options and factory precision.
- CE and ETA certified timber structuresCE marking and ETA-21/0014 European Technical Assessment for the ZTC timber construction system.
- Timber engineering for architectsTimber structure technical coordination for architects — system options, interfaces and manufacturing solutions.
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.