What is perlite? The mineral alternative

Perlite is a natural, non-flammable, non-toxic volcanic rock, which is created when liquid lava comes together with water when oxygen is not present. The original form of perlite sand is the natural glass obsidian. Though it is found worldwide, there are differences in its quality. Vital to good quality is the combined water of crystallisation, of which between 2 and 6% is combined in perlite sand. The higher this percentage is, the more the raw material expands when heated. As the water is released, countless small bubbles form in the liquid rock, these cause the volume to increase by between 10 and 20 times – a process creating light granules with a well-defined capillary structure. For Klimasan-Perlit plaster we primarily use raw perlite from the Greek island of Milos. Containing 2 to 5% water of crystallisation, this perlite sand has the ability to expand enormously. In our special ovens, the raw perlite is expanded at over 1000 degrees Celsius. This expanded perlite is composed of 70% silicon dioxide and is therefore a natural glass (Si2O3). By evaporating the water, cavities (capillaries) are created, which allow the material to offer high quality insulation as well as regulating dampness and noise. This granulated perlite is proven to contain no toxic materials. It is frost resistant, odourless, capillary active and does not burn.

In conclusion, Klimasan-Perlit is a natural insulation material with outstanding features:

  • A comfortable and healthy indoor climate
  • Natural drainage of damp walls
  • Extremely good insulation against heat and cold
  • Easy to apply
  • High load bearing capacity
  • Environmentally friendly
  • Pure mineral raw material
  • Sustainable as it is created from volcanic activity


Wall construction

Klimasan-Perlit, a top grade plaster, and very easy to apply


Uses of the Klimasan products
Interior plaster
Refurbishment plaster
Exterior plaster (render)

Fire safety plaster

  1. Prepare the area you wish to plaster
    -Chip lose plaster away from the wall, exposing the brickwork. Remove any loose plaster and any old mortar
    -Spray apply a level and substantial layer of a mortar from group CSIII (strength 3.5 – 7.5 N/mm2)
    In the case of newly built and brick walls spray the whole area, for old buildings of natural stones spray in dollops covering 50 – 70 percent of the surface
  2. Mix the plaster
    Applying by hand: mix the entire contents of a sack with around 15 litres of clean water in a compulsory mixer or a cement mixer. Mix for a maximum of around five minutes. Do not exceed this mixing time
    Applying mechanically: Commercially available plaster machines with a setting for insulation plaster, or a special Klimasan mixer coil are suitable.
    Get the required mixing coils from manufacturers or ask us
  3. Ensure the correct consistency has been achieved
    Klimasan-Perlit is at the right consistency if the mixed plaster is creamy and sticks to your trowel.
    It often appears to be too dry. Do not, under any circumstances, blend too much water into it – as with traditional mortars or plasters
  4. Trowel up the plaster
    – First, dampen the area you wish to plaster well
    Apply Klimasan Perlit in the same way as traditional plasters – in a creamy state, at least 20 mm thick, from top to bottom.
    – With plaster of over 30mm total thickness apply Klimasan-Perlit in wet layers (max 30mm every layer) in multiple passes. Let every layer set before you apply the next
    – The entire application time amounts to around 4 hours
  5. Level the plaster
    – Smooth over the Klimasan-Perlit plaster with a well dampened aluminium plaster trowel
    -Plaster trowels made from synthetic materials are not as suitable. Under no circumstances use a dry plasterer’s float
  6. Respect the minimum setting time before continuing to work
    Depending on base:

    – For a brick wall background around 1 hour
    Natural stone around 1 to 2/3 hours
    Concrete around 5 hours
    Klimasan-Perlit must dry out slowly. Therefore, spray the plastered surface lightly with water under intensive sun or wind which dries it out quickly
  7. Level the final layer
    – Smooth over the top coat evenly and sand this flat with a lattice plane after it has set
    -You can also carefully rub down (but do not try to rub it completely smooth as you would with a conventional plaster and a sponge plane) Klimasan-Perlit under running water with a sponge8. Select the right finishing plaster
    -As a finishing plaster for Klimasan-Perlit use a breathable pure mineral plaster
    -Preferably with a chalk base in any desired grain size
    -Take note of requirements of regulation EN998-1 (European specification regarding masonry mortars)
    -Use for example lime plaster indoors to create flat surfaces
    – Generally applies to Klimasan-Perlit T1-CS, I, W0
    – Outdoor top coat CS, I
    – Inner layer CS, I

Optimising energy consumption with purely mineral heat insulation plaster

The energy related requirements for the comprehensive renovation of an already existing or historically important building are fundamentally governed in Germany by the EnEV (German energy conservation regulations), which are among the most efficient of such laws in the EU. A deviation from the demands on the existing parts of the building is of course possible in the case of a historically protected building (Section 24, EnEV). Against the background of climate change and scarcity of raw materials, however, we certainly have a moral obligation to take care of energy related concerns with a building of historic importance. Therefore, it is especially important to take the new structural conditions into consideration. In conjunction with restoration there is generally also a change of its use. Mainly the change of purpose or restoration of a historically important building means indoor renovation and insulation, while the outside appearance must continue to look the same as its present condition. This indoor renovation presents a few risks, but also many more chances to open the building up to meeting new demands. One of the big “scares” is the anticipated damp. Most importantly, the dew point – the point in the wall where condensation forms. The indoor insulation causes the old construction to cool, and therefore partially causes a higher level of damp. Added to this there is also rising damp, invasive damp in traditional German “Fachwerk” style timber framed houses, driving rain, condensation, water collecting in the joints of the house, groundwater and percolating water. But all this is just water and not a technical or chemical challenge which cannot be solved. Instead of sealing the walls, insulating them and locking the water out, a popular alternative method of solving the damp problem, it is generally important to choose a construction material which can use its capillary structure to get around this “water” issue. It is therefore of enormous importance, what the applied materials do with the water. This is controlled by the water absorption coefficients. In terms of valuable properties of plaster – along with the λ-value (thermal conductivity) and the u-value (rate of heat loss) resulting from it, the water absorption (w-value) is of at least the same if not even larger importance. Water absorption and water release are only made possible by the capillary action of the construction materials used. Dry building components are the foundation for the sustainable use of every building. Even the professional sphere of the ecologically oriented planner and user offers the view that: “insulation materials must show good insulation values, so that only a little warmth can escape in the winter, and in the summer the heat does not reach the room too quickly. The insulating material must be able to desiccate water well by itself, as even low levels of moisture (2%) can reduce the insulation ability by 50% and result in the danger of damage to the building (Source: ECOworld)”. This requirement cannot however be fulfilled by thermal conductivity (the U-value), a vapour barrier or a vapour retarder. The application of synthetic or alleged “ecologically organic” insulation materials compels the industry to make the rate of water vapour escaping the walls (μ-value) the measure of things, in order not to have to bring attention to the problem of the actual damp. It is much easier to satisfy the market and the one-sided heat loss measurement (U-value) specification by calculating a thermal conductivity value, than by examining sustainability over a long time.  With this there are a range of further advantages for the application of a pure mineral capillary insulating plaster. Compared with the solution of boards, plaster alternatives offer the advantage of the material being able to malleably fit every situation. Especially in such important areas, like window reveals, a thermal insulating plaster can be applied so that the theme of insulation is only of secondary importance. However, the real problem of the damp will be outstandingly solved. It also similarly appears on ceilings and balcony supports. All condensation that arises is taken in by capillaries and diverted by the positive and frictional bonds in these areas. This is especially substantially important with organic building materials such as wood or timber beams. The hygiene and health aspect is well recognised as a huge problem due to the settlement of fungi and other microorganisms. Additionally, there is a further sociological aspect. What happens to all the insulating material if a building one day is demolished, converted or changed in some other way. What kinds of “rubbish” we leave behind for our children is declared by the insulation industry to be “valuable material” for “suitable waste incineration plants” to attain heat or electrical power. The fact is, polystyrene has been declared a hazardous waste in many European countries and must be disposed of in line with this. Finally, the requirement on the fire safety comes in addition to this. The historically protected building should be kept as a testimony to contemporary life for our descendants. Therefore, they should be expensively renovated and kept. In many of these buildings, for example, wood was used for bearing construction parts. Above all buildings of public use which are governed by special regulations and directives (schools, pubs, hospitals etc.) have to fulfil fire safety technical requirements in connection with the renovation and new use. Naturally also in such cases a historically protected building restriction, as well as the economic tenability is questioned. But why shouldn’t you choose a building material which also doesn’t burn, fulfilling the requirements of the German A1 building material class. The fire performance of the pure mineral insulation plaster regarding flammability, heat generation, smoke generation and toxicity leads to it being this class of building material.

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