Thermal insulation paint against mould and condensation

isomaxterm thermal insulation paint

The product is improved in 2021 making it super easy for application!

Mould is a serious problem leading to respiratory diseases, which can be overcome only if the condensation on the outer walls, ceilings and the corners between them is eliminated, because in order for the mould to develop, a high humidity environment is needed, which are the condense droplets.

In turn, condensation is warm air that has reached a cold surface (as it happens in the summer when a cold bottle is taken out of the refrigerator).

After applying thermal insulation paint IsomaxTERM, the surface temperature of the walls / ceilings equalises with that of the air and thus eliminates the possibility of condensation, and therefore mould growth.

IsomaxTERM is a thermal insulation paint against mould, working on the basis of the physical laws of reflection of thermal rays – a different and innovative way of action compared to traditional thermal insulation. It is applied as a final coating internally or externally. In terms of its working consistency, packaging, application technology and decorative qualities, the product is analogous to high-quality acrylic paints. The product is a modern technology made by the established for 30 years Bulgarian manufacturer of liquid waterproofing products – ISOMAX.

The product contains special polymer microspheres that absorb heat only on the surface and immediately radiate 85% of it back. It is this heat-reflecting effect, heat retention (interior) or its repulsion (exterior), that is thermal insulation in the full sense of the term. With IsomaxTERM there is no heat absorption in the structure and it is really thermally insulated. The coating is literally like a mirror for the heat rays. As a result of this reflective effect, heat losses are reduced, about 25% real energy savings are realized and comfort is increased.

When applied indoors, IsomaxTERM reflects back 85% of the thermal energy emitted from heating devices and this way performs as a thermal insulation. This way the loss of thermal energy is reduced to minimum and the ambient temperature is achieved much quicker and kept constant with about 25% less energy.

When applied outdoors the coating of IsomaxTERM reduces the temperature inside the premises by about 5°C. Most cooling equipment is installed on the roofs where in a hot summer day the surface temperature is about 80ºC. Same is with dark-coloured facades. With IsomaxTERM the temperature of a roof/facade falls to 38.3ºC. This way the air-conditioning efficiency is greatly improved, resulting in real energy saving of minimum 25%.

Tests conducted with IsomaxTERM in the Enzo Ferrari Laboratory for Energy Efficiency at University in Modena, Italy in February 2016, not only measured the heat reflection of 84.70%, according to the standard ASTM C 1371-15, but also found an extremely high degree of action of the coating applied outdoors. IsomaxTERM reflects 89.20% of the sun’s rays, according to the standard ASTM E 903-12. Based on these results, a formula calculates total coefficient of reflection of sunlight – Solar reflectance index (SRI), which is used for comparison for all coatings for outdoor use.

thermal insulation paint

IsomaxTERM has an average SRI* = 112.60%, which is currently the highest known result!

For comparison, other similar thermal paints have SRI * = 102% – 106%.

1 liter of IsomaxTERM weighs only 500 grams! Other similar materials weigh 1.0 kg/l, and ordinary latex weighs over 1.5 kg/l. The low bulk density determines the high insulating properties. There are 5 times more reflective microspheres in our product because they are 5 times smaller than the ceramic/glass spheres in similar paints. The coefficient of thermal permeability of a coating of IsomaxTERM is 11 times lower than that of a coating of ordinary paint! This low thermal permeability leads to a high surface temperature of the walls and ceilings of the premises during the winter, which determines the high anti-condensation and energy-saving properties of the coating. The degree of back radiation of heat rays of “IsomaxTERM” is 84.70%, according to the standard ASTM C1371-15. This means that the losses through the final coating are only 15%, which exceeds the efficiency of standard thermal insulation.

The external coating of IsomaxTERM reduces the temperature inside the premises by 4-5°C, which also provides savings of about 25% of the cost of air conditioning of buildings in the summer.

Restoring the functionality of facade thermal insulation systems is a new but growing field for the application of heat-reflecting coatings. It is known from the textbooks in thermal engineering that a thermal insulation works only when it is completely dry! In standard facade plasters, due to natural aging, cracks appear, through which water penetrates. It moistens the thermal insulation, which decreases the thermal insulation performance of the system. The application of IsomaxTERM on the existing thermal insulation restores its properties. The elastic and waterproof coating fills the existing cracks and prevents the entry of water and prevents the appearance of new cracks in the plaster. In addition to the long-term preservation of the thermal insulation system, IsomaxTERM limits the “thermos” effect and provides coolness and comfort in the premises during the summer.

thermal reflective paint

Such paints have been used around the world for more than 20 years, as heat-reflecting coatings reduce the heat absorption of buildings by cooling not only the buildings themselves, but also lower the ambient temperature, thus reducing the so-called “island effect”. “Island effect” is a concept that explains why the temperature in cities is higher than in rural areas – namely the heat absorption from buildings and roads, which taken with a thermal camera from the air shows how cities look like “hot islands”. The photo shows London in this perspective.

The external coating of IsomaxTERM is UV-resistant and lowers by 4-5°C the air temperature inside the premises and also lowers the ambient temperature around the air conditioning systems on roofs and facades, which provides savings of at least 25% summer. It was found that on a summer day with an air temperature of about 30°С, the temperature of the roof surface is over 80°С, and of the facades – over 50°С. According to the report from Modena, with IsomaxTERM this temperature is 39.9°С, which facilitates the work of the air conditioning equipment and also reduces the electricity consumption.

After 7 successful years of offering and promoting a product that most people approach with distrust, because it is an innovation and heat-reflecting paints are unpopular, we have the great pleasure to announce the following:

Based on the experience gained and customer feedback, in recent months we have worked hard in the laboratory and improved “IsomaxTERM” so that it is better in all aspects of use, and unsurpassed thermal insulation, anti-condensation and anti-mold properties to be preserved!

The improvements are:

– The consistency is thicker and more covering.

– Application is super easy, like common paint.

ISOMAX” is a family company founded on May 30, 1990 by eng. Petar Baychev. The company is an established manufacturer of liquid waterproofing produts for 30 years, known for offering the highest quality, superior to other similar materials. All products are our own, patented development, are produced only in Bulgaria and are preferred by all who value quality and know that the cheap is always expensive. Many of the most responsible and emblematic sites and buildings in Bulgaria are made or repaired with waterproofing “Isomax”. See more about us at

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The product is absolutely harmless! The content of VOC (volatile organic compounds) is less than 0.1 gr/l. For comparison, the allowed maximum in the EU is 30 gr/l, and for paints with low VOC content are accepted those in the range of 10-15 gr/l.

This actually means that IsomaxTERM falls into the highest category of paints with zero VOC content. In practice, this means a minimum of odour during application and drying, and complete safety in the long run.

zero voc

Preparation of the substrate

IsomaxTERM is applied onto cement, gypsum, lime surfaces, painted walls and ceilings, well-bonded wallpaper, etc. The basis for the coating must be sound, dry, clean and smooth. To prevent overrun of material it is recommended the surfaces to be primed with IsomaxTERM-primer at rate of about 50 gr/m².

To remove existing mould locally, the affected surfaces should be treated with appropriate products for mould cleaning. Then apply IsomaxTERM over area that should be at least 50 cm wider in all directions. To prevent the occurrence of condensation, which is the needed environment for growth of mould, it is recommended to apply IsomaxTERM onto the internal surfaces of all exterior walls and ceilings, as well as a binding strip at least 50 cm in the angles between exterior walls and interior walls and ceiling. In order to achieve maximum energy saving effect and to have maximum comfort, the heat-reflecting paint should be applied as a finishing coating on all interior walls and ceilings.


Preparation of material

1. Carefully open the lid and by means of a spatula or a trowel thoroughly separate the material from the walls of the bucket.
2. Mix with an electric mixer (stirrer) at high speed (about 1000 rpm/min) until complete liquefaction.
3. If necessary, for easier spreading with roller, the material may be diluted with water up to 3% (30 ml water per 1 liter IsomaxTERM).


Manner of application of IsomaxTERM

Onto preliminary primed and dry surfaces, apply a layer of IsomaxTERM with paint brush or roller with polyamide fibres (fibre length of 10-13 mm).
Consumption for one layer: 0.130-0.140 litres per 1 m² (65-70 g/m²).
Application by brush is recommended for small areas – up to 5 m².
Before using the roller or the brush, it must be moistened with water.

Always stir IsomaxTERM thoroughly!

The roller should always be well and evenly soaked with material in order to move without pressure on the surface and the material to spread quickly without repeating one and the same place. Basically, under well soaked roller, two / three passes in both directions is enough to form the required layer of IsomaxTERM. After the complete drying of the first layer (about 4h at 23°C), further two layers shall be applied in the same manner.

IsomaxTERM can be also applied through spraying, with equipment with air-compression.

Total consumption of material for 1 m² – 0.400 litres (0.200 kg).

The minimum thickness of the final dry coating should be 0.3 – 0.4 mm.

  • Solar Reflectance (SR) ASTM E 903-12 = 89.20%
  • Infrared Emittance (IE) ASTM C 1371-15 = 84.70%
  • Solar Reflectance Index (SRI) ASTM E 1980-11 = 112.6%
  • IsomaxTERM is certified through SRI tests in ЕЕLab, (Energy Efficiency Laboratory), University of Modena and Reggio Emilia, Italy, Test no. ЕTR-16-0027 /2016
  • Thermal conductivity λ = 0.035 ± 0.005 W/m.K
  • IsomaxTERM meets the requirements of EN 15824.
  • Density – 0.55±0.05 g/cm³
  • Viscosity – 1000 – 3000 mPa.s
  • Adhesion – 1.50 N/mm²
  • рН – 7.0 ± 0.5 (neutral)
  • Dimensional stability at high temperature: 100°С
  • Brilliance of the film – completely opaque, according to ЕN ISO 2813
  • Class for reaction to fire: Bs1d0 according to EN 13501-1: Bs1d0
  • Appearance of film (visual) – flat to slight relief
  • Heat penetration factor β = 1.58 W.h0.5/m².K
  • Coefficient of permeability – 0.01 kg/m². h0.5
  • Transfer coefficient of water vapor V= 120 g/m².d
  • Number of diffusion resistance to water vapor μ = 50
  • Drying time at 23°С – 2 h for 1 layer; 12 h – Complete drying
  • Good resistance to wet abrasion and washing – class 3 ЕN ISO 11998
  • VOC free – VOC content less than 0.1 g/l
  • IsomaxTERM can be tinted with common colour agents for acrylic paints

Always stir before use and regularly during application!

Place the lid back tightly onto the packaging of use until the entire quantity of paint is spent!

Air and surface temperature range: 5° C to 25° C.

Cleaning of tools:

Wash the used tools with water before they dry.


Plastic buckets of 2, 5 and 10 litres.


Keep from freezing! Store in the original, tightly closed containers in a covered and dry warehouses, away from direct sunlight and heating appliances!

Shelf life

24 months from date of manufacture in factory sealed package.