Frequently Asked Questions

This page contains answers to the most frequently asked questions.

Cellulose insulation is a blown-in thermal insulation material produced from newspapers or cardboard by fiberizing, with more than a hundred years of history behind it.

The insulation can be installed by dry blowing or by spray-on application (Sidox™). When dry blown, the product can be installed either by free blowing, in which case the product has a settlement value of < 10% that should be taken into account; or by dense blowing, in which case the density of the product is high enough that no  settlement occurs. Spray-on application installations do not settle.

An indisputable advantage of blow-in cellulose insulation is the freedom of shape. It seamlessly fills the insulated space – there are no batt installation errors. The fibre size of Termex Cellulose insulation is 0–4 mm, so it penetrates even the smallest gaps when blown, completely filling the space to be insulated. As a sufficiently airtight material, it also reduces natural convection, meaning the movement of air inside the insulation material due to temperature differences, which saves heating energy.

The price of blowing insulation installation is affected by the space to be insulated, the amount of insulation material, freight, and the difficulty of the installation work. That’s why we always give site-specific offers. Blow-in installation is often cheaper and easier than batt installation because the price always includes the work. Request an offer using the offer form.

Termex is a fire-safe thermal insulation material for three reasons:

1) The insulation material does not melt; it burns slowly by smouldering without losing its volume, even at high temperatures. Its ignition temperature is close to 300 degrees, when the water of crystallisation contained in the fire retardant is activated, binding the fire energy. The charring speed of the insulation material in a fire is 1–2 mm/minute.

2) The insulation material has a high airflow resistance (cf. airtightness), meaning that combustion gases cannot spread uncontrollably in the insulation space.

3) When charring, the fire retardants of the insulation material form ceramic ash that slows down the advance of fire. The European fire class of Termex Cellulose insulation is B-s2,d0. Even demanding REI 90-structures can be realised with it.

Termex Cellulose insulation is a non-hazardous product that can be recycled, converted into energy, or reused. When installing the product, the workers protect themselves from dust with overalls, P2 class dust protection, and work gloves. Normal occupational safety is observed during the installation work.


Termex is a hygroscopic, breathable material that binds and releases moisture with its wood cells, always equalising itself in relation to the humidity of the surrounding air. The insulation acts like wood in terms of moisture. Indoor air humidity under normal conditions does not condense into the insulation material as long as the structure’s airtightness has been taken care of in accordance with good construction practices.

A breathable structure is one that is able to bind and release moisture without the humidity of the indoor air condensing at the dew point. Breathable structures are realised with hygroscopic materials, examples of which are natural fibres and lightweight concrete. We recommend Termex air barrier products for breathable structures.

As a general rule, Termex Cellulose insulation is suitable as additional insulation on top of any thermal insulation. The moisture functions and fire safety functions of the work site must be ensured before retrofit insulation, however.

Check out our Vintit Kuntoon® retrofit insulation service and order a free inspection > to the site