Wooden architecture

Wood – a long-lasting, durable, natural and ecological material.

Wood is one of the oldest building materials in the world, used not only in the construction of residential buildings, but also in the construction of bridges, water supply and sewage networks. Since other building materials (cement, concrete, bricks) have entered the market, the idea has spread that wood has a relatively short lifespan. However, there is no basis for such an assertion: the longevity of wood is confirmed by the wooden log houses preserved in the Russian north, which have an age of 600–700 years. Similarly, in North America, Canada, and Scandinavia, wooden frame houses built long ago demonstrate that improved building materials and solutions can provide a substitute equivalent to brick in terms of durability.

Wood is an excellent building material that offers a good quality of life. It is a natural, environmentally friendly raw material that is resistant to heat and cold. The only factor that must be controlled is humidity. The most crucial aspect to consider in the construction of wooden houses is proper wood processing.

Frame houses for different climate zones.

Economical, high-quality and rational housing construction technology – wooden frame houses. Frame house technology was created in Canada. The natural conditions of North America are similar to those of Northern Europe. The technology of frame house construction is also suitable for different climate zones and geological conditions. By adjusting the parameters of the insulating materials, frame houses can be built in both southern and northern climate zones. Wooden frame houses can also be assembled at low temperatures.

According to Canadian construction experts, wooden-frame houses, if renovated periodically, can last approximately 150–200 years. The structure of frame houses allows for flexibility; therefore, they can withstand even earthquakes (in Japan, 75% of the population uses wooden frame houses, fixing a high shock-absorbing pole inside the building, to which all the house structures are constructed: the walls move together with the pole, but do not collapse). On the other hand, frame houses cannot withstand stronger storms and hurricanes, which are especially common in North America. In Latvia, garden houses have been built using frame construction technology for several decades, but the construction of residential dwellings is also becoming increasingly popular. University of Latvia professor Andris Jakovičs believes that wood is the most suitable construction material for the Latvian climate.

Thermal efficiency: the most crucial thing for thin walls is tightness

Brick and concrete residential buildings with thick walls are typical in Latvia, so there is a misconception that a house with thin walls does not retain heat well. The average wall thickness of a wooden-frame house is 20 cm, but even in cold weather without heating, the temperature decreases by only 2–3 °C per day. If thermal insulation materials are installed during construction, and the tightness of the frame house, on which heat losses depend, is ensured, it is not difficult to heat the frame house and maintain the desired temperature.

Heat in the rooms rises from the heating devices, creating pressure near the structures, including the ceilings, windows, and walls. Warm air is pulled out through the smallest gaps, while in the lower part of the room, the air is rarefied along the floor surface and through the air holes in the floor. Cold air is sucked in through the doors and windows, which must be heated again. This energy loss can only be reduced by increasing the thermal resistance of the structures. The US company “Architectural Energy Corporation” researched to calculate heat losses for uninsulated building structures that were later covered with a remarkably impermeable and heat-intensive insulation material. The results indicated that the basis of heat saving is impermeability. The thermal resistance of the impermeable insulation material layer increases by more than 100% (by thickening the layer from 10 cm to 20 cm), but the thermal energy savings are only 3%, making such an investment ineffective. From the study's results, it can be concluded that investing in ensuring the tightness of house structures is more efficient, as even a thin layer of insulation material retains a significant portion of the heat that escapes from the interior.

The insulation material must allow water vapor to pass through so that the wooden structure in which it is embedded does not rot, mold, or dry out easily due to moisture. Both water vapor and air pass through the insulation material at almost the same speed. In turn, the drying process of building structures is relatively slow, so the air permeability of sufficiently breathable insulation materials can be so low that they can be classified as impermeable materials. By choosing a reasonably impermeable insulation material, air circulation through obstacles can be significantly reduced — at the same time, heating (in winter) and cooling (in summer) costs are reduced.

Frame house construction

Since traditional brick, wood or stone wall building materials must perform several functions at the same time (structure support, heat, and sound insulation), this creates specific construction conditions: to ensure the drying and shrinkage of the building, the wall thickness must be sufficiently large, the foundation of the house must be massive, but the construction time must be relatively long. The technology of frame house construction allows to distinguish the material's bearing, separating and insulating functions. Each stage has its task and corresponding properties: one material ensures the structure's minimum thickness, another effectively retains heat, the third reliably insulates against moisture, and the fourth protects against noise.

The foundations of the building can be monolithic, columnar, or on screw piles. There is no need to build massive foundations, which reduces the construction period and also the price.

One of the disadvantages of frame buildings is their acoustic properties; therefore, special gaskets are built into frame houses that act as sound insulation (the filler provides this). Often, sound-related complaints arise due to the floor’s structure. If the house has two floors, residents may complain about the sounds they hear, such as footsteps on the floor above. This problem can be solved with a sufficiently durable wooden covering, on which concrete floors can be poured later. With frame technology, even five-story houses can be built, but traditionally, this construction method was used for the construction of 1- to 2-story buildings.

Frames are made of dried, calibrated wood. Builders typically choose coniferous trees for their structures because of their desirable properties. Spruce wood is more flexible, while pine is more fragile; however, modern technologies enable wood to be adequately protected from adverse environmental influences. Wood can warp over time, so it must be appropriately incorporated into structures.

The price of a partially finished frame house, excluding the laying of the foundation and painting, can range from €800 to €1,500 per square meter. The frame can be assembled within a few weeks. It is essential to select suitable weather conditions for constructing a frame house, as the building frame is assembled on-site. The wood can be affected by moisture and cold. It should also be noted that a frame house should not be left unfinished and without windows and doors, even for a couple of years, as it would not withstand the effects of environmental conditions. Therefore, it is essential to plan all construction work and allocate the necessary funds accordingly.

Stages of installation of a frame building

The frame up to the roof is divided into three parts — the lower beam, which runs longitudinally to the foundations, edge and internal bars, as well as the crown. Once the wall structures are reinforced, the construction of the roof can begin.

A rubber gasket is placed between the foundation and the lower beam along the entire width of the wall, protecting against moisture and ensuring tightness. Later, the elements of the frame (calibrated wood is more suitable for this) are installed, which are located approximately every 60 cm. The frame materials are connected with nails or screws. Thicker wooden beams are used in the corners and other places required by the construction project.

Later, the crown is strengthened, and the covering is installed. The thickness of the wooden board can range from 1.95 m to 2.45 m, depending on whether a concrete floor will be poured on it and the number of partitions. The total weight of the future roof structure should also be considered.

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When deciding to build a frame house, it is essential to bear in mind that it should not be left unfinished, without windows and doors, even for a couple of years, as it will be vulnerable to adverse

Timber frame houses

Advantages

• Low structural weight (frame houses are 5–6 times lighter than brick houses).
• Relatively short construction time.
• Easily accessible materials.
• Possibility to diversify architectural solutions (construct individual forms and internal layout of the house).
• No need for large construction mechanisms.
• Internal communications (water supply, sewage, heating, and ventilation systems) are hidden inside the walls.
• Easier to modernise.
• Good price-quality ratio.
• Ecological and renewable materials.

Disadvantages

• Less resistance to significant storms and hurricanes.
• Construction requires good weather conditions, when wood cannot be affected by moisture because the structures are assembled on the construction site.
• It is essential to make the house airtight; otherwise, there may be significant heat losses and poor sound insulation.

Prefabricated houses – quick to build and economical

Prefab houses can be built quickly if professional construction workers are employed.

Prefab houses are a type of frame house. When building any type of frame house, the result is almost identical. The difference is the production technology: the house elements for prefab houses are specially manufactured in a factory and then brought to the construction site. All that remains for construction workers is to assemble everything on a pre-built foundation.

Prefab houses are built from factory-produced, assembled panels. The production time for a 150-square-meter, four-bedroom house can range from 3 to 5 weeks, depending on the project's complexity. The panels are made for the main structural elements (walls, partitions, roof). They can be designed with exterior decoration, already assembled doors and windows, electrical wiring, etc., and engineering networks.

The assembly of panels at the construction site is quite smooth – construction work at the construction site lasts 3–7 days (but it requires qualified workers). Since the house elements are taken to the construction site with partial interior decoration, very little work related to the walls needs to be done indoors. Construction work is also shortened because there is no need to wait for the moisture in the house materials to dry out before carrying out finishing work. While the house elements are being manufactured at the factory, it is possible to build foundations, bury communication pipes in the ground and perform other work, thus saving time.

Prefabricated house technology is a very economical, ecological and durable solution, as the structures are made of renewable materials, quickly and without harm to the environment. The process, quality, and deadlines for manufacturing prefabricated houses are not affected by adverse weather conditions, such as wind, frost, or rain, so production of such houses does not stop even in the cold season. Weather conditions also have a minimal impact on the assembly of the house, and the relatively short construction time on the site makes it easier to adapt to changing weather conditions.

Another important aspect is the price of construction work. Since you don't have to worry about transporting materials to the construction site and storing them, you save money. By properly planning the delivery of house elements (panels) to the assembly site and coordinating it with the assembly work, it is possible to avoid unloading the panels on the construction site and assemble them directly from the vehicle.

If you choose an individual panel house project, the price of the house will increase.

The most significant disadvantages: special attention to the foundation and fewer planning options

One of the most critical aspects of building a panel house is the appropriate laying of the foundation and its waterproofing. This is especially relevant in our climatic conditions, when the temperature can drop below 20 °C in winter. This means that the foundations of panel houses must be below the frost line. In Latvia, the ground usually freezes at a depth of 1–1.2 meters, so the foundations must be deeper; otherwise, the ground can lift the foundations due to the freeze-thaw cycle. Unlike conventional frame houses, panel houses are less flexible, as solid panels attached to them can deform or separate at the joints due to foundation expansion or improper assembly work.

Waterproofing is essential for both frame houses and panel houses – water that has penetrated the interior can cause wooden structures to rot. There must be very high-quality waterproofing between the foundation and the panels, as a damp foundation freezes more easily, and moisture can rise along the entire wall to the roof.

If you want to save money, we recommend building a house from the manufacturer's unified panels. Although prefabricated house projects have limited architectural choices, you can still choose an individually developed house project, where panels of specially adapted sizes and shapes are manufactured. However, this will cost significantly more. In any case, the successful implementation of the project depends on how high-quality and accurate the structure is designed. In particular, the airtightness of the house directly depends on the quality of the manufacturing and assembly work.

Panel houses

Advantages

• Possibility of carrying out construction work even in the cold season.
• The house is quick to build.
• Assembly is possible with partial finishing.
• Excellent operational indicators of a wooden prefabricated house (energy efficiency, energy saving, environmental friendliness).
• The technology allows you to create a completely even surface of the floor, walls and ceiling, so it is easier to create high-quality interior decoration.

Disadvantages

• Particular attention must be paid to the quality of installation works, as it directly affects the prevention of thermal bridges.
• The foundation must be poured below the frost-resistant depth (more than 1–1.2 m). Improper pouring can cause cracks in the walls.
• There is little opportunity to choose individual planning. A particular project would cost more.

Log houses: simplicity, warmth, longevity

Although frame and panel houses are faster to build and relatively inexpensive, many people still select log houses – they are the most ecological, as clean, natural, high-quality wood (not compressed wood chips) is used in their construction. Moreover, for the Latvian mentality, it is probably one of the most acceptable construction materials. In houses made of milled or solid logs, environmental influences have little effect on indoor temperature fluctuations. In a wooden house, logs that have warmed up during the day retain heat, and when the logs have cooled down, they evaporate the moisture accumulated in them – this is how the heat and humidity ratio is maintained.

Ancient buildings evidence the longevity of log houses – if the wood is treated correctly, it can last for several centuries. The variety of building materials and the expertise of builders enable log houses to be furnished in a very modern manner. Still, construction workers must do this with experience and knowledge of working with logs.

How to choose the right wood?

Typically, resinous wood, such as pine or spruce, is used for house construction. The reasons are quite simple: this wood is inexpensive, flexible, and durable. Many people may have questions: when is the best time to cut down trees intended for house construction? A log cut in winter is in a “dormant state”, and therefore does not turn green so quickly, i.e. does not change color. If a log house is built from dry logs, the humidity of the logs before joining should be within 20%. Wet wood is not suitable for creating a log house, as it can deform significantly during the drying process. Before construction, the wood must be kept in ventilated rooms; otherwise, it may change color (turn blue or black), start to rot, mold, and change size. Properly dried wood shrinks half as much, withstands greater loads, and is more aesthetically attractive.

What should the logs be?

The thickness of the walls of a log house typically ranges from 15 to 35 cm; they can be round or square, depending on the types of logs used (milled logs). Logs can be round with bark (natural), round turned, sawn on two sides, sawn on four sides, or glued beams. In essence, this is more of an aesthetic issue, although the square logs themselves increase the wall's thickness. However, professionals claim that the most critical factors are how the joining is done, how the work is performed, and what materials are used. There are general principles for this type of construction. According to Jānis Lielais, logs should lie on top of each other, occupying no less than half the width of the log. Internal partitions should also be made of logs if possible. At certain joints of a log house, internal partitions made of logs are required to maintain the structural stability of the house. Door and window frames cannot be fixed directly to the log wall. However, qualified craftsmen can use various design techniques for parts or assemblies during construction.

Foundations

Good builders say that the most essential element of a house is the foundation. Occasionally, log houses may be an exception, as they may not require a foundation, despite needing one. Logs intertwine so tightly that neither frost, nor wind, nor other conditions characteristic of our climate can move them: wood, as a living material, can bend, change shape, color, but does not jump out of the overall house structure. Additional arguments for this statement: if the log house is on a foundation that “walks” under the influence of freezing/thawing, then the walls will not be airtight either, and there will always be gaps between them. For the structure of the log house to properly “settle” over time and be tight, the foundation on which it is built must also be stable. Darjus Sudvojus, director of UAB Tekmega, claims that logs are lighter than masonry walls, so pile foundations are sufficient for them.

Thermal properties

There is a dispute between log house manufacturers and brick construction supporters about the too low thermal conductivity of log walls, which is 1.8 W/m² K. As log house builders confirm, energy losses through a log wall cannot be calculated based solely on the thermal conductivity coefficient of wood. The results in practice show something different: energy consumption is significantly lower than the theoretical calculation data. According to experts, this factor affects the breathing, heat capacity, and moisture absorption properties of logs.

A critical feature of this type of house is the accumulation of excess moisture. That is why a log house feels good even at a temperature of 17 degrees. However, this process can also be the opposite – if there is too little moisture in the air, the wooden wall contributes to it additionally.

Another argument in favor of building a log house: put your hand to the masonry to assess how well the walls are insulated. You will feel the temperature change. When the heating of a masonry room is stopped, the contact of the colder wall with the warm air is inevitable, leading to the formation of moisture condensation. In a log house, this process occurs more slowly, due to the high heat capacity of the log. This property maintains a temperature inside the log that is close to the room temperature. This reduces the likelihood of moisture condensation.

Cracking opportunities

It is vital to avoid cracks at the intersection of the foundation and the first crown. The lower logs must be impregnated, preferably sawn from rot-resistant wood, and a layer of waterproofing must be installed on the foundation. In addition, it is essential to create wide sloping roof eaves and ensure that the foundation does not go beyond the vertical plane of the wall.

Internal partitions are recommended to be made of logs. Rigid construction bricks or plasterboard partitions can cause cracks in the logs.

Log houses

Advantages

• Good sound insulation – thick, solid walls.
• Healthy living environment (atmospheric humidity, little static dust).
• Longevity (up to 3 times greater than frame or panel houses).

Disadvantages

• It is essential to treat the wood properly; otherwise, it may start to rot or deform.
• Wood needs to be maintained (impregnated) regularly.
• More complicated interior design due to the settlement of structures.

Specialist's comment

Artūrs Gredzens, Commercial Director of the wooden house construction company "ARTIVA"

Before expressing arguments “for” or “against” any type of construction – a wooden or brick house – it is first necessary to pay attention to what determines the quality and value of the living environment (not only the house) throughout its life cycle. A very high level of efficiency distinguishes wooden construction in the individual house construction industry. On the scale of values, the artistic performance of the building, energy efficiency, or the market value of the land plot should not be prioritised in terms of importance. Health, longevity, and adaptation are more important than them. Evaluate the overall energy! If aesthetics, traditions, and scientific innovations were respected and the environmental friendliness of the construction system was considered, then the advantages of wooden construction would also be revealed.