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Cellulose insulation in timber houses
Insulation and comfort

Cellulose insulation in timber houses

ZTC installs industrial Isofloc cellulose and wood fibre insulation in controlled factory conditions, reducing the risk of gaps in the insulation layer.

ZTC experience and production facts

35+

years of experience

400+

completed projects

14

European countries

±1 mm

CNC precision

Insulation, indoor climate and sound

Cellulose and wood fibre insulation can positively affect indoor climate. Denser materials compared with mineral wool may help with sound damping, but the final result depends on the project and execution. A+ class depends on the whole building — see also energy-efficient timber houses and A+ solutions.

Insulation performance indicators

ZTC installs insulation in the factory, but final energy performance and comfort depend on the whole building solution and precise execution.

Factory installation
Controlled conditions

Insulation is installed in the factory, reducing the risk of unfilled cavities.

Materials
Cellulose / wood fibre

Industrial Isofloc system for cellulose and wood fibre insulation.

Sound damping
Project-dependent

Denser materials compared with mineral wool may help with sound damping, but results depend on construction.

What affects the final result

  • Insulation layer and structural solution.
  • Membranes, airtightness and on-site assembly quality.
  • Windows, ventilation and building form — beyond wall thickness alone.

An energy audit is usually carried out at design stage to determine the appropriate solution before production.

What clients say about ZTC quality

Google reviews highlight ZTC’s precision, organised process and professional communication.

Google review

ZTC built my house in 2012, and they have done some reclamation work in two periods since then. Only positive experiences with ZTC! Good quality of workmanship and customer support.

Review

We are the small clients of ZTC (because of small house for small kids) but that didn't change the amazing attitude to us and our deal from this amazing company! Even with the smallest business deals ZTC works with perfect attitude with all of clients. Professional, fast, with amazing surprises (!!!) which made us and our clients see and welcome the product with sparkling eyes! We just want to say you - THANK YOU! We wish you all the best! And the quality of kids house is really amazing!

Linda B.

What to consider about insulation

Industrial installation

Isofloc system in controlled factory conditions.

Material choice

Cellulose and wood fibre insulation according to the project.

Energy performance

U-value 0.12–0.15 W/m²K possible depending on construction.

Whole building

A+ class is not wall thickness alone — windows, ventilation and airtightness matter.

Frequently asked questions

Questions about cellulose insulation, technologies 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.

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.

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.

Would you like to discuss an insulation solution?

Send project information to review scope and construction.