Answers
to frequently asked questions

It has been proven by a whole range of tests and practical reports that no insulation material - except for very hard insulation board materials (e.g. foam glass) – is immune from rodent destruction or infestation. The borate additives in our insulation are not classed as contact poisons but as ingestible poisons and therefore we can not offer a prognosis as to whether isofloc insulation will be subject to rodent infestation or not. This fact does not however represent any disadvantage for isofloc compared with other insulation materials. This position is supported by years of practical experience.

American experiments on rats have demonstrated that borates are an effective poison. The most secure method to inhibit rodent infestation is, and remains, the careful cladding of void spaces with robust boarding materials; the avoidance of sources of nourishment is in the vicinity and of course keeping a cat in the house. That isofloc is “more attractive” to rodents can not be proven. The positive telephone feedback we received from the developer of an old house reported that after insulating the loft floor with isofloc using the open blow method, the previously existing marten infestation had ceased.

In any case, it can not be the function of an insulation material to repel rodents. The same applies to insects. This would only be possible through the use of (contact) poisons which would severely impair the ecological quality of the insulation material.

Further documentation on the subject:

• Only available in German: Mice destroy almost every form of insulation material – published in Landtechnik (a specialist journal for agricultural technology and rural building). Edition 2, February 1982, Pages 81-83.
• Laboratory report No. 13110 from the Applied Biological Sciences Laboratory in Glendale, California / USA on the food intake of rodents – also applies to cellulose insulation.

Building materials in Germany are rigorously proofed and classified according to standardised tests to establish their flammability. Generally, the materials are designated as either flammable (B class materials) or non-flammable building materials (A class materials). One of the criteria for this classification is the assessment of the fire origination phase - the combustion point when applying a naked flame to the unprotected material.

Due to the high proportion of organic material within isofloc insulation it is naturally a flammable building material (Fire resistance class B2, flammable as per DIN 4102-1), just like solid timber, most wood-based sheeting and many other insulation materials aswell. This situation will not be changed by any future European standards. Therefore under current regulations, isofloc is suitable for installation in most types of buildings. Exceptions which require “non-flammable insulation materials” include very tall buildings, special-use buildings and industrial buildings. Due to the borate salt impregnation and the carbonisation of the material, the application of flames to the surface of the isofloc cellulose insulation leads to surface charring which is similar to that of charred wood.

The surface of the insulation material smoulders to ash. The ash has an extremely high melting point which means that, in itself, the development of the ash restricts melting even at very high temperatures. The surface smouldering of the insulation helps to preserve the structure of the material and therefore its insulating function at high temperatures. This slows the smoulder process within the material and reduces the burning rate. What seems at first glance as an advantage i.e. the protective function of the carbonised layer, is still regarded by the fire inspector as destruction. Therefore the fire classification awarded to isofloc insulation does not properly reflect its fire resistant properties.

The positive fire resistant properties - from fire resistance classes F30 to F90 - have been extensively documented in tested isofloc constructions. The cladding required for the corresponding F-classes are not more complicated than, for example, those of inflammable glass fibre insulation materials which melt at around 600°C leaving the timber construction unprotected. isofloc does not melt and dependent upon the construction actively increases the effective duration of the F-class. A diverse range of types of fires have proved the positive fire resistant behaviour of isofloc. Some of these are documented in a special issue of the journal "Insulation technology" 3/98 (Natural building materials and fire protection. The fire resistant behaviour of cellulose convinces developers, authorities and the fire services). Original title: Isoliertechnik 3/98 (Naturbaustoffe und Brandschutz, Brandverhalten von Zellulose überzeugt Bauherren, Behörden und Feuerwehr).  

These facts combined with the results of extensive tests on various building components have proven that the principle thermal load (the amount of energy released through the proportion of cellulose) resulting  from isofloc insulation does not represent a problem! The fire inhibiting effects of the surface carbonisation is regarded by many as an extremely important protective factor which, after practical demonstrations in front of developers, authorities and fire services, has led to a number of special approvals. This has meant that isofloc has been employed in a number of construction projects in which the official requirements relating to the class of building would normally demand the use of non-flammable insulation (A-class building materials). For example, in Kurhaus Bad Elster in Germany - where during a subsequent fire isofloc was able to prove its positive characteristics and which also convinced the owners to insulate the new roof with isofloc (documented in the above mentioned article). Another example is the insulation of over 15 public-sector owned, multi-residential houses in Rüsselsheim, Germany.    

Further documentation on the subject: (only available in German)

• Assessment of the fire resistance class B2 for isofloc L (T-B-A02)
• Test certifications for the F-classes – F30 to F90 – for various building components. A special issue of the journal Insulation technology 3/98. (Natural building materials and fire protection. The fire resistant behaviour of cellulose convinces developers, authorities and the fire services).

We are not aware of any test results in Germany relating to the resistance of isofloc or any other cellulose insulation materials to insect infestation. We have also never commissioned such an assessment. The reason being is that we have never received any claims for damages/compensation in this area and therefore we suspect a certain level of resistance to such infestations. We believe that this is due to the addition of borates to our products.   

We are sure that you already know that borates are the most commonly used chemical, timber protection additives to resist the growth of mould and the effects of insect damage. Thereby it is important to know that borates are not contact poisons but ingestible poisons. This ensures that isofloc is not suitable as food source for insects and will therefore not attract them. This is supported by the absence of any claims for damages/compensation. In addition, insects do not possess any mechanisms to neutralise or dispose of toxins (liver, kidneys etc) as humans and most mammals do.

Insects negatively react to the smallest amounts of ingested borates, which underlines their effectiveness as chemical, timber protective agents.

First of all it is important to differentiate between the absorption of liquid water (structural damage or in areas where condensation collects) and the adjustment to the moisture balance based upon local climatic conditions (temperature and relative humidity). In the latter case, the moisture level of isofloc insulation depends upon the amount moisture contained within the air. Due to its physical properties, there is a maximum level for solid timber that can not be exceeded. So, for example, at a room air temperature of 20°C and a relative humidity of 50% (the air has reached half of its maximum possible moisture absorption level), isofloc contains a moisture level of only 9%. At the same air temperature and 80% relative humidity isofloc contains a moisture level of 17%.  Solid timber under the same climatic conditions exhibits a level of approximately 1-2 % more.  A “saturation” of solid timber is unknown and cellulose insulation behaves just like wood.

It is important to know that a certain level of moisture is perfectly normal, is conform with the regulations contained within the technical approvals and does not detract from the thermal insulating properties of the product. That isofloc products have been installed for over 15 years right up to under the roof tiles has shown that liquid water absorbability is not necessarily detrimental.  

Further documentation on the subject: (only available in German)

• Moisture balance isotherms for wood and isofloc at 20°C

It is true that isofloc exhibits a certain natural level of liquid absorbability. In the case of structural damage – and only in this case is this characteristic relevant – one should make a differentiation: If there is only a small amount of water ingress, it must be possible that within a reasonable period of time it will dry out again naturally. This may be achieved through structural means, such as vapour-diffusible constructions supported by technical drying measures, where necessary. If a large amount of water has flown into the insulation, then as a rule this results in an imbalance in the distribution of the borate salts. The material must be removed. It should not be reused, even when dry, as this redistribution of the borates may mean that in certain areas it may no longer conform with the proscribed quality levels (mould growth protection and fire resistance). A sample of the removed insulation can be returned to isofloc for assessment at a small cost.  

Further documentation on the subject: (only available in German)

• Fraunhofer Institute for building physics, Stuttgart (1990). Drying behaviour of CSO-spray-on method applied thermal insulation layers from isofloc (T-F-W01).
• Fraunhofer Institute for building physics, Stuttgart (1996). The influence of an insulation material on the drying-out of lightweight building components (T-F-D03).