Facade plaster for aerated concrete – how to plaster aerated concrete outside the house

For aerated concrete walls to be protected and look better, facade plaster is an essential component. Because of its insulating qualities and light weight, this kind of concrete needs extra care when it comes to external finishing. In addition to making the structure look better, proper plastering prolongs the structure’s life by protecting it from the elements.

It’s important to take into account the special qualities of aerated concrete when getting ready to plaster it. Aerated concrete is more porous and has a higher absorption rate of moisture than regular concrete. For this reason, choosing the appropriate plaster and application method is essential to guaranteeing a strong and long-lasting finish. To preserve the integrity of the aerated concrete, the plaster material of choice needs to be both water-resistant and breathable.

The aerated concrete surface needs to be sufficiently prepared before plastering. This include priming the walls, fixing any imperfections or cracks, and cleaning the walls. A smoother and more consistent application is ensured by the primer’s assistance in strengthening the bond between the plaster and the concrete. Paying attention to these preliminary steps can have a big impact on the outcome.

A base coat and one or more finishing coats are the first layers applied when applying facade plaster to aerated concrete. Before applying the next layer, make sure the previous one has had time to completely dry. This multi-layer method improves the plaster’s strength and longevity while also offering superior insulation and weather protection. A professional and durable finish can be achieved during application by using the appropriate tools and techniques.

Lastly, it’s important to select the appropriate kind of plaster. There are several options, such as synthetic, lime-based, and cement-based plasters. Various types offer advantages and suitability based on the particular needs of the project. Making the right decision for your aerated concrete facade can help ensure that it stays gorgeous and protected for many years to come. You can do this by speaking with experts or carrying out extensive research.

Step	Description
1. Clean the Surface	Remove any dirt, dust, or loose material from the aerated concrete. A clean surface helps the plaster stick better.
2. Apply Primer	Use a primer suitable for aerated concrete to improve adhesion. Apply it evenly and let it dry completely.
3. Mix Plaster	Prepare the plaster according to the manufacturer"s instructions. Mix until you get a smooth, workable consistency.
4. Apply Base Coat	Spread a base coat of plaster onto the surface. Use a trowel to apply it evenly and create a rough texture for better grip.
5. Add Reinforcing Mesh	Embed reinforcing mesh into the base coat while it’s still wet. This helps prevent cracking and adds strength.
6. Apply Finish Coat	Once the base coat is dry, apply a finish coat. Smooth it out and make sure it’s evenly applied.
7. Cure the Plaster	Allow the plaster to cure properly. Keep it moist if necessary to prevent it from drying out too quickly, which can cause cracks.

Positive qualities of aerated concrete

If you’re thinking about using aerated concrete to build a house, you should thoroughly weigh the benefits and drawbacks of doing so. The block has many more benefits, and by using the right materials and technologies, the negative effects on the lifespan and quality of the house can be successfully mitigated or eliminated.

• Environmentally friendly material and safety – can be used in the construction of residential buildings without worrying about the health and lives of people.
• Creating a pleasant microclimate in the house – due to the fact that the material “breathes” and does not create a greenhouse effect inside.
• Light weight of aerated concrete – which allows you to save money on transportation, loading/unloading, installation without the use of special equipment, as well as on choosing a less durable foundation.
• Fire resistance – aerated concrete can withstand open fire for about 5 hours or more, preventing it from spreading.

• Frost resistance – at the level of 50 freeze/thaw cycles or more.
• High level of the heat supply – due to the presence of closed pores with air in the material, it provides the maximum level of thermal insulation and does not require the arrangement of additional layers, and in winter allows you to save up to 35% to pay for heating.
• Optimal strength – sufficient for the construction of low-rise buildings.
• Large dimensions and good geometry with low weight – this makes laying walls from blocks simple, quick, and can be done with your own hands.
• It is perfectly processed – aerated concrete is well cut and sawn, which is also important and facilitates the construction process, and also makes it possible to implement the most original ideas in terms of shapes, configurations, etc.d.

Typically mention the hygroscopicity of aerated concrete, which can be effectively avoided by selecting the right finishing materials, plaster being the most important choice.

The most important thing is to make sure that the materials used for both interior and exterior work protect aerated concrete from moisture and do not deteriorate its vapor barrier properties.

Aerated concrete homes require special considerations when plastering the exterior in order to ensure durability and aesthetic appeal. In addition to providing weather and environmental protection for the aerated concrete, facade plaster improves the aesthetics of the house. It’s critical to select the appropriate plaster type and apply it correctly for optimal results. Plaster must be applied in layers after the surface has been prepared and the proper bonding agents have been used. You can protect your aerated concrete house while creating a stunning, long-lasting finish with the correct methods.

When it is necessary to carry out work

Aerated concrete plastering is frequently done right away after the box’s construction is finished. However, professionals advise beginning with interior design and waiting three to four months after completion before beginning exterior work. The only possible exception would be if the house is regularly threatened by moisture and urgent external work is required.

It’s best to wait at least six months after the house’s construction is finished before beginning any finishing touches. This is required to give the moisture that gathered in the pores during construction enough time to escape from the gas blocks entirely. The ideal way to schedule the work is to have the facade work take place between April and September after a six-month wait.

Is it necessary to insulate the facade of the house before plastering

Insulating the walls is a good idea before plastering. Since aerated concrete has relatively high heat-saving indicators, each situation is evaluated individually to assess whether thermal insulation is feasible.

• If the thickness of the aerated concrete wall is less than the parameters specified in the standards. So, usually the walls are made 30-40 centimeters thick, but for the northern regions, the optimal thickness is considered to be at least 60 centimeters.
• Insulation is important if aerated concrete blocks are laid not on special glue, but on a cement-sand mixture, due to which the seams are not too thin and cold bridges are created, leading to heat loss.
• When arranging a reinforcing belt, a concrete frame, which have high thermal conductivity, also contribute to the formation of cold bridges.

It is noteworthy that aerated concrete homes with heating are required by SP 50.13330.2012 to have increased vapor permeability from the interior to the exterior (this ensures the optimal functionality of wall structures). Plaster should have vapor permeability of at least 0.12 and insulation; aerated concrete exhibits vapor permeability at the level of 0.11-0.23 mg / (m * h * Pa).

While there are several materials that can be used for thermal insulation, mineral wool is the best option because it satisfies all requirements and prevents condensation and the formation of a dew point.

Because mineral wool slabs are lightweight, they do not strain the walls or foundation. Additionally, because of their adhesive connection, installing a frame or drilling holes in the blocks can be omitted. You can complete the easy task by yourself.

Types of plasters for aerated concrete

When deciding what kind of aerated concrete to plaster outside, you should research the best available mixtures and take into account all possible options. Ultimately, the plaster’s quality will dictate the finish’s longevity, the blog’s degree of moisture protection, and the overall dependability and durability of the building.

• Vapor permeability – it is desirable that the coefficient is higher in comparison with the layer of the previous material (aerated concrete or a layer of thermal insulation).
• Frost resistance and the ability to withstand any weather conditions.
• Elasticity, to eliminate the likelihood of cracks.
• Good adhesion specifically to aerated concrete.

Aerated concrete blocks can be finished with a variety of plaster types, each with its own composition, characteristics, cost, and other factors.

Mineral

Mineral-based mixtures enable the material to be installed in thin layers. The compositions, which can be made by hand, are typically made specifically for using with aerated concrete. White cement, lime, and filler in the form of marble chips or any other material are the main ingredients of mineral plasters.

Plaster compositions on the market are presented in a fairly limited choice of colors, but can be painted. Coloring compositions and pigments must be vapor-permeable. They are painted not only for decorative purposes, but also to protect the coating from moisture, since it is afraid of exposure and can quickly become unusable.

Silicate

The foundation of these compositions is potassium liquid glass, which serves as the mixture’s binding agent.

• Ease and ease of application.
• Good vapor permeability.
• High level of moisture resistance.
• Ability to paint the coating.
• Service life of about 25 years.
• Affordable cost.
• Decorativeness and aesthetics.

Silicone

For the most part, silicone-based facade plaster outperforms other plaster compositions in terms of its operational and technical attributes.

• Excellent water-repellent ability.
• Ability to do all the work yourself, without the need to involve specialists.
• High level of resistance to any atmospheric phenomena.
• Sufficient level of vapor permeability.
• Long service life.
• Texture, a large selection of fillers to give the layer a decorative effect.
• Elasticity – this quality eliminates the risk of cracks both in the plaster layer and in the aerated concrete itself.

This kind of solution is pre-made and comes with usage instructions that must be visible on the composition’s packaging.

Acrylic

Due to its low vapor permeability coefficient, acrylic-based plaster is noticeably less effective than other compositions designed specifically for aerated concrete, despite showing excellent strength and decorative qualities. This could cause condensation to form on the acrylic plaster facade, which would have unfavorable effects.

Cement mortar – calculation

Finding an appropriate plaster composition for aerated concrete in Moscow or the surrounding areas is not difficult because the modern market offers a wide variety of options. However, a lot of artisans are still considering using cement mortar to finish the exterior of a home made of aerated concrete. This choice is deemed inappropriate for several reasons.

• The cement mixture does not demonstrate sufficient adhesion for reliable adhesion to the smooth surface of the aerated concrete block. Then a dense solution with a large weight can simply become covered with cracks and peel off.
• Moisture gets from the cement mortar into the aerated concrete, reducing adhesion and violating the integrity of the plaster layer due to uneven and accelerated drying.
• Poor vapor permeability of the cement mixture does not allow compliance with building codes, as a result, microclimatic indicators are violated, which is especially important in residential premises.

Calculating the amount of finishing material is not difficult. Assuming a layer thickness of one centimeter, the packaging for the ready-made mixture typically lists the consumption per square centimeter. All you have to do now is multiply the number of square meters (which you get by dividing the wall’s height by its length) by the layer’s centimeter count and the number of kilograms by the amount consumed.

Therefore, assuming that the plaster consumption is 8 kilograms per 1 m2 with a thickness of 1 centimeter, you will need the following mixture to finish a wall of 10 square meters (5 length and 2 height) with a layer of 3 centimeters: 10 x 3 x 8 = 240 kilograms.

You must be aware of the volumes and proportions of the materials if you intend to make the plaster mixture by hand. In addition, the wall area and layer thickness are considered.

• Volume of solution per square centimeter: 1 x 0.025 = 0.025 m3.
• With a cement to sand ratio of 1:4 per square meter, you will need 0.02 cubes of sand and 0.005 m3 of cement.
• To plaster 60 square meters you will need 0.3 cubes of cement and 1.2 m3 of sand.
• But 0.3 cubes is not 300 kilograms, since the density of cement is high and one liter contains 1.5-1.7 kilograms. This means you will need 300 x 1.6 = 480 kilograms of cement. The required number of kilograms of sand is also calculated: 1.2 x 1.55 = 1860 kilograms.
• It turns out that per square meter of plaster you will need 7.5-8.5 kilograms of cement and 31 kilograms of sand.

The most common plaster mixes for aerated concrete blocks

It is best to choose pre-made mixtures from reputable manufacturers when selecting facade plaster mixes for aerated concrete, as they ensure superior material quality, longevity, and adherence to all required specifications.

When used to finish facades, an acrylic mixture offers excellent strength in a thin layer of coating. The plaster resists frost and is unafraid of outside forces. It is typically utilized in homes that have waterproofing and ventilation.

– A composition for decoration that has a "bark beetle" effect. It exhibits good vapor permeability and decorative indicators, and it can be applied to mineral wool and any other type of insulation that is paintable. The mixture has a strong resistance to various influences and a low consumption.

For an aerated concrete home to be both long-lasting and aesthetically pleasing, plastering the exterior is a crucial step. Homeowners can protect their investment from weather damage and improve the appearance of their property by choosing the appropriate facade plaster and applying it correctly.

A plastering job that is successful requires preparation. Make sure there are no loose particles and that the surface of the aerated concrete is dry and clean. Plaster adhesion can be significantly increased by using a primer made especially for aerated concrete, resulting in a more durable and long-lasting finish.

Consider aspects like breathability, flexibility, and weather resistance when selecting a facade plaster. These characteristics are essential for avoiding moisture accumulation and cracks, which over time can cause structural problems. Plasters with a silicone base, for example, provide good water resistance while still letting the walls breathe.

The quality of the finish is also greatly influenced by the application methods used. Layer the plaster thinly and evenly, giving each coat enough time to dry. This process guarantees a smooth, even surface and aids in the prevention of cracks. Professional results can be achieved and the work made easier with the use of appropriate tools, like a trowel and float.

In conclusion, careful preparation and execution are needed when plastering the exterior of a home made of aerated concrete. It is possible to create a stunning and long-lasting facade that will shield your house for many years by selecting the appropriate materials and applying them according to instructions. In the end, it will be worthwhile to invest the time necessary to ensure structural integrity and curb appeal.

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