A selection of thermal insulation material
What to pay attention to when purchasing thermal insulation material?

An offer of thermal insulation materials on Polish market is very wide. While choosing a product it’s particularly necessary to consider whether it holds essential hygienic certificates and the declaration of conformity, and whether it has been manufactured in accordance with the applicable standards.

The most important parameter of a thermal insulation material is heat transfer coefficient (λ). The lower it is, the higher the insulation properties of the material are. Heat transfer coefficient (λ) for polystyrene and mineral wool are similar and amount to between 0.032-0.045 W/(m∙K) for polystyrene and 0.035-0.045 for mineral wool.

It’s also crucial to pay attention to physical features of the material: cohesiveness, rectangularity, elasticity, hardness, possible defects.

What is to bear in mind while using polystyrene?
  • Shape and look of polystyrene should be impeccable. It must be rectangular, without deformations, defects and dense.
  • Polystyrene is not resistant to organic solvents such as benzene, toluene, acetone and the like, therefore it is necessary to check the chemical composition of the materials that are used together with it.
  • It’s important to remember that polystyrene is not fully resistant to impact of weather conditions. Exposed to their impact is subject to yellowing, and over a period of time crumbles, thus it cannot be left unprotected for a period longer than 2 months.
  • I cannot be used in areas particularly exposed to fire. Although polystyrene is non-flammable, it melts at +800C. A lot better fire-retardant material is mineral wool, which starts melting at 1000ºC.
Which insulation material to choose: polystyrene or mineral wool?
Both polystyrene and mineral wool feature very good thermal insulation properties. A decision, which material to pick during the building insulation, must be based on other features and parameters of these materials.

A polystyrene choice is very beneficial due to economic and application reasons. Polystyrene is a lot easier material as far as installation and handling are concerned. It is neutral to skin and mucous membranes, does not contribute to any irritations. Due to its low weight, nearly ten times lower than mineral wool, it is much more convenient for transport and storage. The cost of polystyrene and additional accessories necessary to perform the system (adhesive, anchors) will be lower than mineral wool. In addition, there is no fear that the building construction, which is insulated, will be overloaded.

On the other hand, mineral wool is ideal for buildings particularly exposed to fire, or high temperatures. Due to high acoustic insulation, mineral wool is perfect for areas where high volumes of noise occur. Mineral wool sheets (with regular fibre system), demonstrate high elasticty, are easily installed on irregularly-shaped buildings.

What is the diffrence between plain and grooved polystyrene sheets?

Plain polystyrene sheets are installed tightly by edge to edge method, whereas grooved ones by tongue and groove method. In case of plain sheets all gaps must be carefully filled with low expansion spray foam or polystyrene. It is not necessary in case of grooved sheets as they overlap. It significantly eliminates the problem of thermal bridges.

What polystyrene thickness to use so that our house is warm and complies with the applicable regulations?

Generally, for most external walls 10 - 15 cm is enough. However, in order to determine the thickness precisly it is necessary to calculate U heat transfer coefficient. The type and thickness of a construction material, the wall was made of, plays a crucial role. According to the Regulation of the Minister of Infrastructure on technical conditions the value of U coefficient cannot exceed 0.3 W / (m² • K).

What is to bear in mind while using mineral wool?
  • While carrying out thermal insulation works with mineral wool it is necessary to remember about PPE - gloves, goggles, mask.
  • Facade must be covered. It’s not allowed to wet mineral wool.
  • It’s not allowed to use - acrylic plasters with low vapour permeability on facades insulated with mineral wool.
What plasters to apply on mineral wool?

Mineral wool features very high vapour permeability, therefore it is necessary to use plasters which hold also similar properties i.e. mineral, silicate or silicone plasters. Then we obtain an insulation layer, which allows water vapour to be released easily outside from the gap.

Acrylic plasters shouldn’t be applied, which are products of dense structure. In case the wall is wet, there is a risk of condensation in the insulation layer and consequently the development of destructive phenomena, such as corrosion or plaster flaking.

General recommendations
Why to take advantage of FOVEO-TECH S thermal insulation system?

When using the entire FOVEO-TECH S thermal insulation system you are provided with guarantee and all accompanying benefits. Change of one of the components is only a seeming saving. For example: by using a standard adhesive to insulate a single-family home (250 m2), which is not a part of the FOVEO TECH S system, can result in saving only several dozen PLN, but losing the guarantee and all benefits.

The European Technical Assessment ETA 15/0022 is the document that confirms the highest performance of FOVEO-TECH S system. The European Technical Assessment is the most important document confirming the quality and durability of construction materials in Europe.

In what weather conditions should facade insulation be performed?

While performing FOVEO-TECH systems it is necessary to avoid work in direct strong sunlight, wind and rain. In the above mentioned situations the insulated walls must be protected with a dense protective mesh. Application temperature for adhesives, primers, undercoats, plasters and facade paints should be between +10 ° C and +25 °C - following the recommendations provided in the labels of the products. In case of lower temperatures it is recommended to apply DZ 10 Foveo-Tech winter additive, which accelerates bonding of plasters and facade paints. Thanks to it, it is possible to carry out plasters and painting of facades at low temperatures (from +0 ° C to +10 °C) and increased air humidity.

What quantity of products to buy?

Prior to placing an order for thermal insulation materials, it is essential to carry out a thorough measurment of the facade surface. Next, it’s necessary to subtract the number of doors and windows and add the area of jambs. It’s necessary to remember that during jambs handling the consumption of materials increases by 10%.
“Consumption calculator” - available at www.foveotech.pl - will be helpful while calculating the material consumption.

Installation of thermal insulation material
Is it possible to apply a thicker layer of adhesive on polystyrene if the walls are uneven?

It is allowed to level irregularities up to 1-2 cm. It is assumed that the adhesive layer between the wall and polystyrene sheet cannot exceed 1 cm. In the event of larger irregularities the wall must be levelled e.g. with cement and lime mortar.
In each situation after installing polystyrene sheets, the entire surface must be abraded with a polystyrene rasp.

What anchors to use while installing thermal insulation material?

A technical design should include conditions for mechanical anchoring. The design should include the number of anchors, their position, with taking into account the building height, edge areas, their length and type, as well as the document number of the permit. It’s possible to install polystyrene sheets by using plastic anchors, and lacing anchors in case of mineral wool.

How many and how long anchors to use while insulating with polystyrene?

It’s recommended to use at least 4-5 anchors per 1 m2. In the building corners it is required to increase their number from 6 to 8 anchors per 1 m2. The depth of anchors should be dependent on the substrate type and polystyrene thickness, however, the anchoring depth should be at least 6 cm in case of solid substrates, and 8 cm in light substrates made of autoclaved aerated concrete, expanded clay aggregate etc. In the event of masonry units the anchor must go at least through two walls of the unit. Application of mechanical anchors cannot result in twisting and lifting of polystyrene sheets.

How many and how long anchors to use while insulating with mineral wool?

It’s recommended to use at least 6-8 anchors per 1 m2. The depth of anchors should be dependent on the substrate type and mineral wool thickness, however, the anchoring depth should be at least 6 cm in case of solid substrates, and 8 cm in light substrates made of autoclaved aerated concrete, expanded clay aggregate etc. In the event of masonry units the anchor must go at least through two walls of the unit. Application of mechanical anchors cannot result in twisting and lifting of mineral wool sheets.

Is it necessary to “anchor” polystyrene in a single family house with a loft?

Additional anchoring of polystyrene to second floor of the building is not required. It’s important so that polystyrene sheets are installed carefully by edge and pointwise application. Polystyrene sheet should be covered with approx. 1 cm of Foveo-Tech Adhesive for polystyrene of Foveo-Tech Adhesive for mineral wool, min 60% of sheet’s surface.

What is the reason of strengthening corners and areas near windows and doors?

Very often cracks occur in poorly performed corners of windows and doors. They are a result of increased stress - it’s essential to bear in mind that the building is slightly “working” all the time. To prevent them it’s necessary to apply strips of a reinforcing fibreglass mesh at an angle of 45°. Dimensions of the strips should be at least 20 x 30 cm. Strengthening with strips of a reinforcing fibreglass mesh is also recommended in areas particular exposed to mechanical damage - near windows and doors as well as corners.

Reinforcing layer performance
When are we supposed to perform a reinforcing layer?

In case of polystyrene the reinforcing layer must be performed on dust-free sheets, not earlier than 3 days after their installation. If the polystyrene is not covered with the reinforcing layer within 14 days, it’s necessary to estiamte its condition - yellow and dusty sheets must be abraded by sandpaper.

Similarly, the reinforcing layer can be performed after min. 3 days after installing mineral wool sheets. Prior to works commencement it’s necessary apply a thin layer of KW 12 Adhesive and then wait until it starts bonding.

What fibreglass mesh to use to perform a reinforcing layer?

To perform the reinforcing layer it’s necessary to take advantage of a fibreglass mesh of at least 145 g/m2 weight. Prior to installation the mesh cannot be stored in conditions exposed to direct impact of weather factors, especially the sun, which contributes to extending of the mesh and, consequently, - a visible deformation while installing it on the wall.

While installing the reinforced mesh strips they must overlap approx. 10 cm. Overlaps cannot be performed in joints between polystyrene sheets. If reinforced corners with fibreglass mesh are not used, the external corners must be protected on both sides with fibreglass mesh of approx. 10 cm.

What is necessary to pay attention to while performing a reinforcing layer?

The reinforcing mesh should be precisely embedded in the adhesive, it cannot be visible. Also, it cannot be installed directly on the layer of thermal insulation material.

Is it possible to apply plaster on the reinforcing layer at a later date?

If we are not able to proceed with insulation works, it is allowed to leave the reinforcing layer without plaster. However, it is necessary to protect it with a special base coat, depending on the subsequent plaster - PA 10 base coat for acrylic plaster, PT 20 Silicate base coat for silicate plaster and PN 30 Silicone base coat for silicone plaster.

If works were stopped to 3 months, then the protected facade can only be washed prior to plaster application, but if the period is longer, then it is necessary to apply a suitable base coat again.

Which plasters are suitable in areas exposed to biological corrosion?

All plasters available in the FOVEO-TECH offer contain special biocide systems which prevent biological corrosion from development. The technology protecting from destructive impact of algae, fungi and mould, called “BioCare technology”, provides clean indoor air and protects health of the people living there.

What plasters are suitable for facades particularly exposed to dirt?

TN 30 Silicone Plaster is a product resistant to all dirt, which features very low absorption. This feature facilitates water to flow smoothly of the coat surface and makes the plaster feature self-cleaning properties. Also, TT 20 Silicate Plaster is recommended, whose application contributes to low static electricity of the facade, which consequently prevents dirt particles from depositing.

What plaster to use in areas with high traffic volume?

The best solution is to apply plasters which contain top-quality elastic resins - TA Acrylic Plaster. They feature an enhanced resistance to dynamic tensions, and consequently are more resistant to cracks in the coat.

Can FOVEO-TECH plasters be applied mechanically?

Yes, FOVEO-TECH plasters can be applied both mechanically and manually - by taking advantage of a spray gun or spray unit. The following plasters are particularly recommended during mechanical application: TA 11 Acrylic Plaster, TT 20 Silicate Plaster and TN 30 Silicone Plaster.

Why should dark plaster be applied to max. 10% of the facade?

In the event of performing insulation of buildings it is recommended to avoid dark plasters whose light reflectance value is lower than 20%. Such plasters should be used in max. 10% of the facade. It is assumed that light reflectance value for white colour is 100%, and 0% for black colour. Facades performed in dark colours absorb sunlight a lot more than those in light colours. Excessive heating of the plaster may lead to significant deterioration of the properties of the entire system, especially if it was performed by taking advantage of polystyrene. High temperature can lead to its degradation.

If we run out of plaster during application and we buy the very same colour, will there be any difference in colour shade?

If the plaster was ordered directly at the manufacturer, then the sample of the plaster is kept for the entire period of its useful life. Then, we can order the plaster without worrying about the difference in colour, provided that the purchased plaster was not exposed to impact of weather conditions. If the plaster was acquired at a distributor with a tinting machine, there is a possibility that the batch ordered will be prepared on the basis of other product base batch or colour. However, the differences in shade colour are insignificant, often unnoticeable.

It is important not to start the plaster application without being certain that we have enough product to complete the operation. It’s not recommended to apply on one surface plasters from two different production batches.

Does the grain size of the plaster affect thermal insulation properties?

The most important element of the insulation layer, which determines the U heat transfer coefficient, is thermal insulation material - polystyrene or mineral wool. The values of thermal conductivity coefficient (λ) of plasters of various thickness slightly differ from each other, but their effect on U coefficient is negligible.

How to carry out facade during winter?

In case of lower temperatures it is recommended to apply DZ 10 Foveo-Tech winter additive, which accelerates bonding of plasters and facade paints. Thanks to it, it is possible to carry out plasters and painting of facades at low temperatures (from +0 ° C to +10 °C) and increased air humidity.

How to perform a correct maintenance of the facade (cleaning, washing)?

The most efficient way to clean the facade is to use a pressure washer and surface-active detergents. The facade should be cleaned with horizontal stripes from top to bottom.

Facade painting
Is it necessary to season mineral plaster prior to painting?

Yes, mineral plaster prior to application of acrylic and silicone facade paints should be seasoned at least 4 weeks, and for silicate paint min. 3-5 days.

Is it necessary to prime the substrate prior to paint application?

Prior to paint application the substrate must be primed in order to level its absorption and avoid discolouration. Depending on a paint type, it is necessary to apply a suitable primer, following the recommendations on the label.

How to avoid discolouration while applying FOVEO-TECH paints?

Above all it is necessary to follow the recommendations provided in the label of the product, particularly as regards application temperatures and conditions. It’s necessary to prime the substrate first and make sure, prior to paint application, that the we have a sufficient amount of the paint. It’s essential to use the paint from the same production batch. In the event of applying paints from different production batches, it’s necessary to mix them prior to application.

Is it necessary to paint the facade twice, if the first coating covered the surface well?

Yes, the purpose of facade paint application is not only to obtain a relevant decorative effect but also to protect the facade from various hazards, e.g. biological ones.