Thermo-systems and components

Service Description

Thermo-systems and components

The energy crisis and the countless fuel-related studies about the fuel consumption to heat the houses or other types of buildings have shown that the thermo-insulation of the buildings, protecting them from outside temperatures, positive or negative, is a problem that requires a particular attention: an adequate thermo-insulation is the first thing that we can do to conserve and use the energy and resources efficiently, and especially to reduce the monthly energy consumption expenses.

Even if you live in the block, you can instinctively realize that if you open a window in the winter (which is usually positioned just above the radiator), much of the heat radiated by it will be lost. And if, we say, your neighbor, who also has a central heating system like you, does not heat his apartment, the wall of separation will remain cold: automatically, you consume more energy to ensure a comfortable temperature in your own house.

On the oposite, in the summer you want to keep as long as possible the cold air provided by the air conditioner, so keep the windows closed and the blinds pulled down. In fact, closing or opening the window is the least gesture that you can do to preserve the temperature inside the house. The problem is actually due to a poor thermal insulation of the facade walls and other building elements in contact with the exterior (foundations, roofs, terraces, etc.).

The thermo-systems: general considerations

By trying to protect the facades of the houses from the bad weather with the help of wet finishes as plaster and /or paint, people made the first kind of rudimentary thermo-system for their houses. The thermo-systems have evolved lately, thanks to the discovery of the new insulating materials and more efficient combinations: today, most manufacturers are looking for solutions from compatible materials that meet the need for the thermal insulation of houses and can be used both for new construction, as well as for the thermal rehabilitation of the facades of the old buildings.

The thermo-system, as seen now, refers to the thermal insulation of the exterior walls of a building, no matter how they are made, on the masonry or reinforced concrete structure or even on light wood or metal structures.

In order to achieve notable results in terms of the thermal performance of a building, there must be a continuity between the thermo-insulation of the walls (thermo-system) and the foundation and the roof, the interruption of them may lead to the appearance of thermal bridges which, in time, may favor the appearance of the condensation, respectively the degradation of both the facade finishes and the structural elements, beams, pillars, or of the interior finishes.

 The thermo-insulation of the exterior walls 

An equally important issue is the thickness of the thermo-insulating material. This is calculated depending on how the wall is made (masonry or lightweight structures) and especially depending on the type of materials that the wall is made of, the orientation of the building, etc. The calculation involves both the behavior of the materials at outdoor temperatures and their steam behavior, and it is called hygrothermal calculation.

Making a thermo-system

An efficient thermo-system depends on two factors: first of all the thermal insulation materials used, and secondly the adhesive used. Each material has specific features and is recommended according to the climatic conditions at which the building is exposed. Here is the brief of how to make a thermo-system.

Adhesives for thermo-systems

It is recommended to use adhesives dedicated to thermo-systems. Depending on the substrate, masonry, concrete, BCA or cement-based or wood-based panels in case of constructions build ona lightweight structures, each manufacturer can offer solutions that meet these requirements.

Thermo-insulating materials

Each material has its own specifications. Its choice is closely related to the thermal insulation requirements for each building, the climate zone in which it is located. Also, each material has specific installing instructions, given by its adherent qualities, the structure on which it is installed, permeability, etc. Consequently, the adhesive used in each one is also different from one insulating material to another.

Expanded polystyrene

The thermo-insulating material is white (regardless of the manufacturer) and is delivered in 1 x 0.5 m boards, slightly rugged to facilitate bonding of the support layer and the adhesion of the mass to the spatula.

In general, it is recommended to use a product with a density of 15-18 kg / m³ (more rigid) to prevent the damages from the mechanical action of the plaster.

A newer version is the expanded polystyrene with graphite granules (gray color) with thermal-insulation capacities sensitive upgraded to the regular expanded polystyrene. Both materials are hardly permeable to both water and steams, and the results of a correct choice and a fitting installation can be quantified in significant savings in energy consumption for heating or cooling. The installation can be done both on the masonry structures and on the lightweight structures, using an adhesive recommended by the manufacturer and by additional anchoring with special dowels with wide bloom. Using some inappropriate adhesives can lead to the removal of the thermal insulation from the support layer over time.

The basalt mineral wool

It is a product specially designed for such applications, with the fiber placed perpendicular on the faces (for better compressive strength), does not absorb water and the fibers are waterproofed throughout the section. Generally, the manufacturers’ recommendations must be respected according to needed adhesives to achieve good results. The installation conditions are the same as for polystyrene, with the amendment that the product is delivered in the form of strips with sizes of 1.20 x 0.20 m.

Extruded polystyren

It is used only in the base area and it is in fact the continuation of the basement or foundation thermal insulation. It is not recommended to be used on the facade due to a relatively large linear expansion coefficient.

Accessories for the installation of the thermo-insulating materials

Apart from the installing adhesive, there are some elements necessary for fixing the chosen thermal insulation material. Depending on the installation stage, these are wide-bloom dowels, profiles and reinforcement mesh.

Wide-bloom dowels: these are the fixing elements required for additional fixing of the thermal insulation material on the facade. They are generally made of plastic and have different sizes depending on the thickness of the thermo-insulating material.

The reinforcement mesh: It is placed above the insulating material and it is included in the spatula mass, in order not to allow the cracks in it or in the joints between the boards.

Metallic installing profiles: these are made of aluminum or steel sheet and are generally used in places exposed to mechanical action, sockets or for the edge reinforcement.

The spatula mass

It is made from the adhesive used for bonding the thermal insulation boards and it has the role of smoothing the surface and providing the support for the wet finish of the facade.

The plaster / paint

The finish layer has a decorative role, but at the same time it protects the system against bad weather or mechanical actions. There are several options:

– Finishing with decorative plaster;

– Exterior decorative paint finishing;

– “Visible brick” type finishing;

Depending on the choice made, compatible adhesives, primers and grouts with the entire system are recommended.

As a completion, you can use decorative profiles, door frames, windows, slugs or other façade decorations, and their installation must be done before the finishing installation.

Stages of the thermo-system installation

In general, the thermo-systems manufacturers, regardless of the base material, offer all packed materials, relying on what is called their compatibility related to their behavior in time. As we have shown above, the installation conditions are similar and must be followed according to the manufacturer’s specifications.

Preparing the support

Considering the multitude of construction execution solutions, the thermo-systems have adapted to each type of support. The support, for example the exterior of the walls, can be made of masonry, concrete, plaster, cement or wood, each of which has its own specifications and each one needs pre-conditioning preparation to install the thermo-system. It is recommended that the surfaces be cleaned of dust and cleaned of marks of mortar, efflorescence, oils or fat. If there are bumps, it is recommended to bring to the wall quota, respecting the drying time. For supports based on cement or wood boards, it is recommended that they be carefully installed in order to obtain perfectly flat surfaces.

Installing of the thermo-insulating material

The actual installation of the insulating materials is done in three steps, the first being the thermo-insulation of the base, then passing to the connection between the base and the facade, finally arriving with the thermo-insulation of the facade. Here is what the details should be taken into account during the installation.

For optimum results, there are some simple rules to follow:

• The installation is done starting from the base, using a metallic profile to allow easy installation of the thermo-system.
• The thermo-insulating material boards or strips are used to prevent appearance of the thermal bridges in one direction. It is recommended to press the tiles to one another, avoiding the adhesion introduction into the joints.
• In front of the windows and doors it is recommended that the joints between the boards do not continue in the extension of the edges of the openings.
• Assembly of the woodwork – it is recommended that it be made on a blind window case or on a load-resistant thermal insulation material (usually on extruded polystyrene) to allow the thermo-insulating material to be returned to the window or door and to prevent the formation of the thermal bridges.
• To the corners (in or out), it is recommended to weave the plates and assemble the protection profiles.
• Damaged boards with broken, cracked corners, etc. are not recommended.
• Do not install the dowels until the adhesive layer has strengthened. There are several installing possibilities for the dowels, the choice being made according to the number of necessary joints. Depending on the type of support, plastic or metal nail dowels may be used. The recommended number of dowels is 6 pcs / sqm and can be up to 10-12, depending on the height and speed of the wind in the area. The size of the rosettes is about 68 mm in diameter for fixing the polystyrene boards and about 140 mm for mineral wool strips.
• It is not recommended to make grooves in the depth of the thermo insulating material.

Mistakes made of during the installation of the thermo insulating material layer

Generally, during the installation of the thermal insulation material, mistakes can occur that would influence the construction process.

To avoid them, we recommend the following:

• The joints between the polystyrene boards are not filled with adhesive, but are filled with polystyrene or polyurethane foam;
• Do not screw the dowels prior to the polystyrene adhesive time. This may vary from manufacturer to manufacturer.
• For full masonry, it is recommended that the dowel should be at least 5 cm long, and at the masonry made of hollow brick – at least 8 cm. Also, the dowels with polyamide bolts or steel bolt will be selected, depending on the nature of the wall (full or hollow);
• The bonding of the polystyrene boards to supports such as BCA or old masonry is only done after a primer has been applied to reduce the absorption of the substrate;
• In the case of hollow brick walls, the dowel is not fixed by the percussion because the brick can crack; it is recommended, in turn, to fix the dowels by screwing.
• Fixing of the reinforcement net is achieved only by incorporating it in the layer of polystyrene adhesive. In this way, the reinforcement net is sandwiched between two layers of adhesive.
• After applying the second layer of polystyrene adhesive, the surface should be allowed to strengthen and only the plaster rough case (primer) and the structured decorative plaster can be applied.

The finishing

Depending on the finishes which are to be used, it is recommended to follow basic rules:

• Making decorative elements, frame profiles, slugs or other decorative elements involves the use of prefabricated or conformed elements on the site. They can be placed on a layer of adhesive mortar, reinforced with glass fiber net, and if they are larger, additional mechanical fixing is recommended.
• When you are applying the decorative plaster or paint, it is advisable to insure the required amount of material on the site to avoid overlapping which can modify the final image.
• Work continuously from one edge to the next, following the manufacturer’s installation instructions.
• For placing the “visible brick” boards it is recommended to install them with joints bricks and then grouting them with waterproof grout.
• For special expansion joints, special profiles will be used.

Important recommendations

In order to obtain satisfactory results and to prevent the thermal bridges from coming into contact with other building elements, it is good to keep in mind that there are several possible types of solutions. Below are some of the most common situations on the construction sites regarding the details of joining other building elements.

Details about the base

In general, the thermal insulation of the base is the continuation of the thermal insulation of the basement walls or foundations. It is recommended to use a finishing resistant to dirt, mechanical action and moisture to allow an easy maintenance. The connection between the base and the facade can be done in three ways, depending on the base plan in relation to the façade plan, and the first thing to keep in mind is that a correct solution can prevent the thermal bridges in this area.

The base removed from the facade. It is a commonly found solution due to the fact that most of them do not thermo-insulate enough or do not thermo-insulate the base of the building at all. In case that after the calculations, it turns out that the solution is pertinent, the connection between the thermo isolation of the base and the facade one should be sealed to prevent the occurrence of a thermal bridge.

The base in the same plan as the facade. It is a less-used, but perfectly all right. In this case, it is recommended to place a plinth (the dimensions remain at the architect’s discretion) made of a material resistant to mechanical actions, natural or artificial stone.

The base out of the facade. It is a more “classic” detail, it is necessary to consider the continuation of the thermal insulation and its protection with a decorative profile with larmier to prevent the water leakage directly to the socket. In general, the profile of the base is made of thermo-insulating material and it is desirable to have a protection against the mechanical actions.

Details of voids – doors and windows

The thermal insulation around the door and window voids requires an extra attention to avoid the thermal bridges. It is recommended to install the woodwork on a blind window/door case to allow the thermal insulation back to it without covering the frame of the window. The net reinforcement is made on the entire surface of the facade, aiming at the corners of the voids to double and pose in diagonal way to the main net in order to prevent cracks in the finishing layer.

Details about overhanging eaves, attic:

• It is recommended to place the insulating material on the facade until it is overlapped with the thermal insulation material of the roof. It will be considered to pass the protective foil under the cover over the thermal insulation of the facade.
• The supporting profile of the eave will be installed after strengthening of the spatula mass.
• In the case of the attics (on circular or non-circular terraces), depending on their height, it is recommended to place polystyrene on the horizontal side and protect them with a metallic or decorative profile. In both versions, there must be a larmier to prevent the water leaking directly on the facade.

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