Because of its lightweight and insulating qualities, aerated concrete is a widely used building material. But it comes with its own set of difficulties, just like any building material, especially in terms of insulation. Using polystyrene foam is one practical way to improve an aerated concrete home’s thermal performance. The advantages and things to think about with this insulation method will be discussed in this article.
Because of its superior durability and heat resistance, polystyrene foam is a flexible and popular insulation material. It adds an extra layer of protection against moisture and temperature changes and increases the home’s energy efficiency when applied to aerated concrete walls. This is particularly advantageous in areas with severe weather.
We will examine the usefulness of using polystyrene foam to insulate aerated concrete walls in this guide. We’ll go over the procedures, equipment, and safety measures required to guarantee a smooth installation. Whether you’re designing a new construction or remodeling an existing building, knowing how to
Aspect | Details |
Material | Polystyrene foam for insulation |
Benefits | Lightweight, easy to install, good thermal insulation |
Installation | Apply adhesive to the panels, place them on the walls, and secure with fasteners |
Considerations | Ensure proper ventilation to prevent moisture buildup |
Maintenance | Inspect regularly for damage and repair if needed |
- Choosing the insulation material
- Calculation of insulation thickness
- Insulation of walls made of aerated concrete blocks
- Preparation of walls
- Insulation board installation
- Exterior decoration of the heat -insulator from polystyrene foam
- Insulating the floor with polystyrene foam
- Ceiling insulation
- Video on the topic
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- How foam is attached to aerated concrete
Choosing the insulation material
Experts say that it is more expedient to insulate a structure made of aerated concrete from the outside than from the inside of the house: firstly, the useful area of the room is not lost; secondly, the "dew point" shifts beyond the aerated concrete blocks. To insulate aerated concrete buildings from the outside, a variety of materials are used: mineral wool, extruded polystyrene foam (penoplex), polyurethane foam and polystyrene foam (expanded polystyrene). Expanded polystyrene is the most popular due to its low thermal conductivity, durability and low cost. This material is fireproof due to the fact that it contains anti-peren. Also, the advantages of the material include ease of processing and installation: it is easy to cut into pieces of the desired shape, and slabs of standard sizes (0.5 x 1, 1 x 1, 1 x 2 m) are conveniently attached to walls made of aerated concrete. The thickness of the material (from 20 to 100 mm) allows you to create a sufficient heat-insulating layer (if necessary, the panels can be folded in half). Also, to order, factories produce non-standard sheets of expanded polystyrene with a thickness of up to 500 mm. That is, for insulating aerated concrete with polystyrene foam, there is a large selection of finished products.
Calculation of insulation thickness
You must perform a quick calculation to find the thermal insulation layer’s thickness. Reference tables provide the information we need for the computation. The total required heat transfer resistance (Ro) for walls, which is measured in m²•°C/W, is standardized by SNiP. The wall material’s (Rst) and the insulation layer’s (Rut) combined heat transfer resistances equal this value: Ro= Rst+ Rut. As an illustration, we select St. Petersburg (Ro=3.08).
The formula R= δ ⁄ λ is used to calculate the heat transfer resistance, where δ represents the material’s thickness (m) and λ denotes its thermal conductivity coefficient (W/m•°C). Assume that the 300 mm thick D500 aerated concrete blocks (λ=0.42 according to the reference table) are used to build our home. Then, the wall’s correct heat transfer resistance in the absence of thermal insulation is Rst=0.3/0.42=0.72, and the insulation layer’s heat transfer resistance is Rout= Ro-Rst=3.08-0.72= 2.36. We select lightweight polystyrene with a density of 10 kg/mᶖ (λ=0.044 W/m•°C) as our heat-insulating material.
The heat-insulating layer thickness can be computed by applying the formula δ=Rут•λ. Polystyrene with a density of 10 kg/mᶟ has a thermal conductivity coefficient of λ=0.044 W/m•°Ρ.
Insulation thickness δ = 2.36•0.044 = 0.104 m, i.e., standard polystyrene slabs 10 cm thick are acceptable for our home based on norms and regulations.
We verify our estimates for the temperature at which condensation forms in walls, or the "dew point":
The graphs demonstrate that the heat-insulating layer contains the condensation zone, which is the region where the wall temperature lines and the "dew point" temperature coincide. Even at -30˚C outside air temperature, the condensation zone does not reach the aerated concrete. In conclusion, our thermal insulation layer calculation is accurate; that is, an aerated concrete wall will not become wet even at very low temperatures.
Suppose you choose to simply purchase material that is 5 cm thick and don’t want to perform any calculations. With all other things being equal, let’s examine which region the condensation zone will be located. To give clarity, here is a graph:
It is evident that moisture develops in both the aerated concrete and the thermal insulation layer. The building’s walls lose some of their ability to retain heat due to the presence of water, whose thermal conductivity (λ≈0.6) is much higher than that of expanded polystyrene and aerated concrete. This phenomenon is known as a "cold house."
Insulation of walls made of aerated concrete blocks
Expanded polystyrene boards are commonly used for insulation purposes, even though they reduce the "breathing" properties of an aerated concrete house when used externally. It is quite easy to arrange a thermal insulation layer independently thanks to simple technology.
Preparation of walls
Since the surface of aerated concrete blocks is fairly smooth, all that needs to be done to prepare the walls is to remove any adhesive mortar drips near the interblock seams. If any potholes develop during construction, we fill them in using repair cement mortar. Next, we apply an antiseptic solution over the whole wall to stop the growth of mold and mildew. We prime the walls to enhance adhesion when gluing polystyrene boards to aerated concrete after the antiseptic has dried.
Insulation board installation
Using specialized adhesives, we install polystyrene foam sheets on the building’s walls. Adhesives include ready-made mounting adhesives in aerosol packaging (Tytan Styro 753, Ceresit CT 84 "Express", Soudal Soudatherm, TechnoNIKOL 500), liquid adhesives (Bitumast), and ready-made dry mixes (Ceresit CT 85, T-Avangard-K, Kreisel 210, Bergauf ISOFIX). Adhere the glue to the boards in multiple locations on the surface and along the edges.
Crucial! Solvents and other chemical components that can erode polystyrene foam’s surface or alter the material’s structure shouldn’t be present in adhesives.
It is possible to install slabs at room temperature ranging from -10˚Ρ to +40˚Ρ thanks to several adhesives. On the other hand, professionals in the building industry advise performing thermal insulation work in dry, windless conditions and at a minimum temperature of +7˚C.
Attach the first bottom row of foam plastic slabs with glue to the building’s entire perimeter before attaching the subsequent rows. Lay the slabs in a checkerboard pattern, pressing them firmly to the wall surface. Use a level to ensure that the installation is correct.
Crucial! The panels are arranged end to end in the corners of the structure, meaning that the panel at a 90-degree angle rests against the panel from the end of the building that extends by the thickness of the sheet in one row. The procedure is carried out in the opposite order in the following row.
We additionally fasten each sheet using special dowels with large caps, or "umbrellas," which should not contain any metal parts, after the adhesive composition has completely dried (about one day). The dowel itself and the central nail need to be plastic because they rust and cause more cold bridges to form in the heat-insulating layer. Five to six dowels are needed for each sheet, depending on its size.
Create a hole in the gas concrete wall and heat insulator layer using the perforator. Next, clog the dowel and insert the fixing nail with the aid of a hammer.
We move on to the final wall decoration once all attaching dowels have been installed.
Exterior decoration of the heat -insulator from polystyrene foam
Following the polystyrene foam’s installation, finishing work is required because of its low strength and susceptibility to ultraviolet radiation.
Using a unique plaster solution or adhesive composition, we first attach the fiberglass reinforcing mesh to the top of the polystyrene foam, preventing cracking and enhancing adhesion. Apply a layer of finished decorative plaster once it has completely dried. This level of external finish is sufficient to give the heat insulation layer the strength it needs.
Polystyrene foam insulation is a practical way to improve comfort and energy efficiency in an aerated concrete home. This technique provides an easy-to-use and affordable way to minimize heat loss, maintain consistent indoor temperatures, and cut energy costs. Because of its strength and low weight, polystyrene foam is a great option for this application since it offers dependable thermal insulation without significantly increasing the weight of the structure. Aerated concrete’s inherent insulating properties can be enhanced with an additional layer of polystyrene foam to provide homeowners with an energy-efficient and well-insulated home.
Insulating the floor with polystyrene foam
Expanded polystyrene sheets with a density of 20–30 kg/m⅖ are used to insulate concrete floors. In this manner, we apply expanded polystyrene slabs:
- we make a preliminary leveling fill (it is done if the difference in the height of the base exceeds 5 mm), let it dry;
- we prime the surface;
- we attach a damper tape to the lower part of the walls along the entire perimeter of the room;
- we lay a layer of waterproofing on top of the screed (ordinary polyethylene is quite suitable: at the joints the material is laid with an overlap of at least 10 cm, we bring it onto the walls – at least 20 cm; we fasten everything with construction tape);
- we lay polystyrene sheets on the floor according to the tongue-and-groove principle in a checkerboard pattern (the tongues must completely fit into the grooves);
- we lay a vapor barrier and reinforcing mesh on top of the heat-insulating layer;
- we make a screed of the required thickness.
Note: This insulation method reduces the room’s height by 10-15 cm, but it is very effective.
When it comes to floor insulation, polystyrene foam boards and polystrene concrete are both suitable options. Polystrene concrete can be used to create a screed because of its low thermal conductivity coefficient (λ = 0.05 ÷ 0.07 W / m ° C). We mix the required components to create the filling solution ourselves. You can either purchase a ready-made dry mix or use 20 kg of cement, 12.5 liters of water, and 0.125 m³ of polystyrene foam granules. Following polystyrene concrete insulation, we install the floor covering and, if needed, create a finishing screed.
Ceiling insulation
Indoor ceiling insulation is a successful application for foam plastic. Usually, for these uses, thin sheets that are 5 cm thick are employed. Attaching the boards to the ceiling is like laying on a wall outside. The only distinction is that adhesives and plaster mixtures meant for indoor use—which are less expensive than those meant for outdoor use—can be used.
Utilizing polystyrene foam as insulation for an aerated concrete home can be a cost-efficient and useful approach. Because of its superior thermal insulation, this material can help keep interior temperatures comfortable all year round. Additionally, it acts as a moisture barrier, which is advantageous for aerated concrete constructions in particular.
Because polystyrene foam insulation is comparatively simple to install, both professional builders and do-it-yourself enthusiasts favor it. Because of its low weight, it doesn’t significantly increase the wall’s weight, which is crucial for preserving the aerated concrete’s structural integrity.
Polystyrene foam has insulating qualities, but it can also lower energy bills by preventing heat loss in the winter and maintaining a cooler home in the summer. This efficiency helps reduce long-term utility costs while also helping the environment.