Current Trends in Construction – Poland
Attractive system buildings made from autoclaved aerated concrete
Single Family Houses
Architects have great freedom to act in designing detached single family houses. It is easier to meet pertinent construction requirements since these can be more readily implemented than with apartment buildings. With single family houses, there are hardly any technical aspects that make it difficult to fulfil legal requirements.
Single family houses are mainly executed by small construction companies on behalf of a (future) building owner. For the latter, the high quality of construction materials, system solutions, their durability as well as confidence in these materials are important. Just mere uncertainty or negative opinions about a product on the market can cause building owners to speak out against the choice of a material. For a contracting company, it is important that the construction technology is well-known and can be executed easily. Even if the company has never worked with AAC, this material is so easy to process that it can be produced rapidly and reliably even with inexperienced employees.
Although the contracting company might not make the final decision on the construction material, it can however influence this choice.
Masonry blocks made from AAC are often utilised in constructing single family houses. Shapes of individual buildings and general understanding of AAC construction methods cause that larger precast concrete components are hardly used.
Terraced and Semi-Detached Houses
Attention must be paid to interactions with neighbouring dwelling units when constructing terraced and semi-detached houses. This mainly concerns fire and sound protection requirements for the partition walls dividing the dwelling units. These standard requirements are met by planning double walls between the dwelling units (segments). The technical joint created in this way between the segments guarantees good acoustic decoupling of the neighbouring units. Double walls between segments in terraced and semi-detached houses have been used for many years.
Terraced houses, in a similar way to single family houses, are usually performed by small construction companies. The same aspects have to be taken into consideration as during the execution of single houses. Property owners in such projects are primarily small real estate companies, whose clear preference is for brand name products and rapid construction methods.
Terraced and semi-detached houses can also have a very individual appearance. They are often characterised by quite varied façade geometry and, for this reason here as well, AAC blocks have proven to be the best solution in erecting such buildings.
AAC was employed in constructing exterior walls, load-bearing inner walls and partition walls in the terraced houses illustrated.
The exterior walls were made of AAC blocks with a density of 500 kg/m3 and 24 cm in thickness plus a thin joint and tongue and groove connection. These exterior walls were implemented as sandwich walls with a 15 cm thick thermal insulation layer made from polystyrene. Double walls made of AAC blocks with a density of 500 kg/m3 and 24 cm in thickness were planned between the dwelling units. The joint width between the partition walls was 4 cm and was filled with mineral wool, thus allowing noise protection requirements to be fulfilled. The partition walls were executed in 10 cm thick AAC blocks with a density of 600 kg/m3.
Apartment buildings are constructed by large investors. These are mainly real estate companies, i.e. commercial investors. What matters most to them are short construction times, low material costs, brand name products, general acceptance of the materials in question plus acceptable technical quality. This type of construction projects is carried out by general contractors, who in turn engage smaller contracting companies (differing trades) for various construction jobs. These small companies then undertake the work in each phase of construction. They are mostly companies acting on their own accord who implement their construction works in line with an established schedule.
Potential purchasers, i.e. customers of the investor, show greater preference for traditional technologies in the apartment block sector. Contracting construction companies are not always able to dispose of enough qualified and experienced employees because pricing plays such a major role. This is why simple, traditional technologies have proven to be the best solution, so that such construction projects do without precast or semi-finished precast component walls.
AAC Construction Method Development
As has been mentioned above, the development of AAC products is continually advancing and driven by, market demand. Not just the products themselves, but the entire wall systems are subject to this development and evolution. This has been proven by investigations, conducted by Solbet together with the Silesian University of Technology, into AAC structures over a number of years. The increasingly frequent occurrence of weather anomalies and difficult construction sites (e.g. mining areas) require special, individually adapted, construction methods. Guidelines for designing bulkhead walls made from AAC will be prepared from the findings of these investigations into wall structures.
What AAC manufacturers offer is the subject of continual change as the history of AAC demonstrates. AAC manufacturing technology enables concrete products to be adapted rapidly to altered market demands. Solbet, for example, disposes of such flexibility and can switch over its production to larger elements if needed. In Poland, AAC blocks have been utilised for a long time. Now, elements with larger dimensions can be produced and utilised, such as module blocks, wall and floor slabs, and even entire preassembled walls. However, precast component technology has not achieved a breakthrough in the area of AAC. The current trend towards individually designed and unique buildings has demonstrated that AAC blocks are the best solution in executing buildings – often supplemented by other system construction components such, as reinforced supports, concrete slabs and U-shaped elements. Influence can also be exerted in this matter by contracting companies, which are mainly specialised in erecting AAC masonry walls, or – lacking skilled staff – can quickly train their employees in erecting AAC block walls. Up to the current time, every attempt to introduce new large dimensioned products onto the market in Poland has failed, although it would certainly facilitate the construction progress.
SOLBET Sp. z o.o.
ul. Toruńska 71
86-050 Solec Kujawski, Poland
T +48 52387 4211
F +48 52387 4200