Is golden age of wooden architecture approaching?
The wood is now highly fashionable building material. It is ecological, natural, durable and it has survived the test of time. And while many people associate individual houses with solid masonry, wood frame, timber frame and log houses are becoming increasingly popular. What are their pluses and minuses?
Wood is a durable, resistant, natural and environmentally friendly materialWood is a durable, resistant, natural and environmentally friendly material
The wood is one of the oldest building materials in the world. It is used not only for housing construction but also for bridges, water supply, drainage. The dominance of other building materials (cement, concrete, bricks) led to believe that the life cycle of wood is relatively short-lived. However, this widespread belief was incorrect: the longevity of the wood is confirmed by preserved timbered houses with age of 600-700 years in northern Russia. Old wood frame houses built in North America, Canada, Scandinavia also prove that improving building materials, modern trends and solutions enable us to find a substitute with the hardness equal to masonry.
High-quality wood barrels have special properties. Due to porous structure and a relatively low weight, the wood is a good heat insulating material. Thermal expansion is so relatively small that it does not have any impact on the structures.
The wood is a great building material that provides a good quality of life. It is a natural, environmentally friendly raw material, resistant to heat and frost. The only factor that must be controlled is humidity. The proper treatment of wood is the most important aspect of building wooden houses.
Wooden houses: simplicity, warmth, durability
Although frame and panel houses can be built quickly, are relatively cheap, many people still prefer log houses which are environmentally friendly because for their construction a pure, natural, high-quality wood (rather than compressed chips) is used, in addition, possibly, for any Lithuanian at heart it is one of the most acceptable building materials. In addition, the environmental effect in the wooden house has no influence on the internal heat alterations. The logs of a wooden house retain heat accumulated during the day and when it cools down, the accumulated moisture evaporates by itself, this way heat and humidity ratio is maintained.
The longevity of the log houses is testified by the ancient cottages. Properly worked and impregnated wood can endure a few centuries. Those who think that wooden house dictates simplicity may rest assured. Today, a variety of building materials, expertise and artifice of builders allows to equip a log house in a very modern style but the work must be done by people with experience and expertise to work with logs, otherwise, this may cause a lot of problems.
How to choose the right wood?
pine or fir wood is chosen. The reasons are quite simple: the timber is relatively cheap, elastic and firm. Many people may have questions about the best time to cut the wood for construction of a house? Timber harvested in winter is in the state of sleep and does not turn blue so fast i.e. change color. If the log house is being built from dry logs, their humidity before construction must be up to 20 percent. Wet wood is not suitable to build log houses from trimmed logs because when drying it can severely deform. If poorly ventilated it can change color (become bluish or even black), start to rot, the mold may occur and its dimensions may change. Properly dried wood is 2 times less likely to "sit”, is capable of withstanding greater loads and has a better aesthetic look.
What kind of logs are needed for construction?
Log home wall thickness usually is within the range from 15 to 35 cm, they can be rounded (as is now fashionable in North America) or square. Wooden balks can be rounded cortical (natural), round peeled, sawn on the two sides, sawn on four sides and glulam. In fact, it is more an aesthetic issue, although square logs automatically increase the thickness of the wall. However, professionals claim that the most important factor – quality of log notching works and the materials used.
There are general principles for this method of construction. According to JSC “Tekmega” director Darius Sudvojus, logs must be laid down on one another at the elevation not narrower than ½ of the thickness of the log. Interior partitions must also make the most out of logs. When building a log house, it is necessary to build internal walls to maintain the stability of the house construction. Door and window cases cannot be fitted directly on the log walls. However, skilled artisans may use a wide variety of fixing or knots forming nuances during construction.
Foundations
Good builders say that the most important element of the house is the foundation. Sometimes, it is believed that a log house can be an exception: allegedly, this type of house needs foundation but it can do without it as well. Logs engage so tightly that neither freezing nor wind or other common phenomena in our climate cannot be set them in motion: a tree is a living organism and it may twist, alter its shape and color but it but will not break out of the common construction of the house. Moreover, if log building will be on the foundation, which "moves” because of the frost, then its walls will not be leakproof and there will be cracks. For the log structure to “settle” neatly over time and be airtight, its basis on which it is built must also be stable. Darius Sudvojus "JSC Tekmega" states that, because log dimensional balks are lighter than masonry walls, it is sufficient to build them on pile foundations.
Thermal properties
The log home manufacturers and brick construction supporters often argue because of too low thermal conductivity of the log walls, which is about 1.8 W/sq. m K. Log home builders claim that energy losses through the log wall cannot be calculated solely based on wood thermal conductivity coefficient. Practical results say otherwise: with large resistance, power consumption is significantly lower than the theoretical calculations data indicates. According to specialists, this factor is affected by the respiratory, heat capacity and moisture absorption properties of the logs.
A very important feature of this type of house is to accumulate excess moisture. That's why we feel good in a log house even at 17Co degrees. However, this process can be reversed – if there is too little moisture in the air the wooden wall will add to it.
Another example, aimed to increase your trust in the construction of a log house – place a palm of your hand to the stone, even well-insulated wall. You will feel the change in temperature. Stop heating the brick room, the inevitable contact of the colder walls with warm air enables moisture condensation. In the log house, this process is slow due to the high heat capacity of the logs. Because of this property, the inner half of the log maintains the nearest temperature which is in the room. This reduces the possibility of rapid moisture condensation.
Possibility of cracks forming
It is important to avoid cracks at the intersection of foundation and the first wreath. Lower logs must be impregnated, preferably cut from a rot-resistant wood and waterproofing layer installed on the foundation. In addition, it is important to provide a wide perch of a pitched roof and make sure that the foundation is not protruding from the wall.
It is recommended to shape the internal partitions from the logs. The rigid construction bricks or drywall partitions may cause logs to overhang or cracks to occur.
Log houses
Benefits
• Good sound insulation because of thick, solid walls.
• Healthy living environment (humid atmosphere, low static dust).
• Long life (up to 3 times higher than the frame or panel houses).
Limitations
• An adequate treatment of wood is necessary, otherwise it may start to rot or warp.
• It is necessary to perform wood maintenance (impregnate) more often.
• More complicated interior finishing due to house “settling” down.
Panel houses - rapidly built and economical
Professional workers can rapidly build a block house.
Panel house is a type of frame houses. The result of the construction of any kind of frame houses is almost identical. The only difference - manufacturing technology: home elements for panel houses are specially manufactured in a factory and then transported to the construction site. Workers only need to install everything on the foundation.
Panel house is built from factory produced panels. 150 sq. m. 4-bedroom house production can take 3-5 weeks - it depends on from the complexity of the project. Also, it is important whether only main structural elements (walls, ceilings, roof) are produced, or they will be with exterior finish, already fitted with doors and windows, electrical wiring, and so on.
It is a fast construction -works at the construction site take 3 - 7 days (but this requires skilled workers). Since the house elements are brought to the construction site come already with a partial interior finishing, just a few walls related works are left to be done. Construction work time shortens further because there is no need to wait until the house is dry so that the interior finishing works can be done. In addition, while the house elements are manufactured at the factory, the foundation can be installed, communication conduits connected and other tasks are done to save time.
This is a particularly economical and environmentally friendly solution because constructions are made from renewable materials, quick assemblage, without harming the environment and it is durable.
Panel house production process, quality and deadline are not affected by bad weather - wind, cold or rain, so the production of such houses does not stop even during the cold season. Weather conditions have little influence on assembly of such house - a relatively short work time on the construction site makes it easier to adapt to the weather.
Another important aspect is price for construction works. Since there is no need to transport building materials to the construction site, and find how and where to store them safely it allows to save money. Correct planning of house elements (panels) transportation to the assemblage site and coordinating with assemblage works schedule it will eliminate the need to unload the panels on site because they can be taken for assemblage directly from the vehicle.
If you will choose an individual panel house design, the house price will increase.
The biggest drawbacks: a special focus on foundations and fewer layout options
One of the most important aspects of building panel house - suitable installation of foundations and waterproofing. This is especially relevant in our climatic conditions in winter the temperature drops below -20°C or even lower. This means that the foundation of panel house must be below the frost limit. In Lithuania, usually, ground freezes 1-1.2 meters deep, so the foundation must be deeper, otherwise, due to frost-thaw cycles of the soil may lift the foundation up. Unlike conventional frame houses, the panel houses are less elastic: coupled massive plates due to the expansion of the foundation or improper installation may crack or even split in half.
As with the frame houses, waterproofing is important for the panel houses too - if water gets inside it can rot wooden structures. Thus, between the foundation and the panels, there must be a high-quality waterproof membrane because moist foundation freezes easier, in addition, moisture may start going up over the entire wall and up to the roof.
Another aspect which disappoints all panel house builders - poor choice of planning options if you want to save money and build a house from the unified panels of the manufacturer. Otherwise, you can choose an individual project, by which specially adapted panels will be produced but it will cost significantly more. In any case, quality and precision of building design will determine the further success of project implementation. Airtightness quality directly depends on production and assemblage work.
Panel houses
Benefits
• The ability to carry out the construction work during the cold season.
• House is quickly built.
• Assembled with a partially finished exterior.
• Perfect panel house performance indicators (energy saving, environment-friendly).
• The technology makes it possible to create perfectly flat floor, wall and ceiling surfaces, making it easier to carry out high-quality interior decoration.
Limitations
• Full attention must be paid to quality of the assemblage work on which airtightness depends.
• The foundation must be cast below the frost line (over 1-1.2 meters). Improper casting can break the walls.
• Few options to choose from in individual planning. The original project design costs more.
Frame houses for different climate zones
Wooden frame houses Economic, high quality and rational housing construction technology. Frame houses technology was developed in Canada. North American natural conditions are like ours but the frame house construction is suitable for different climate zones and geological conditions: by altering parameters of insulation materials, the same type of house can be built both in warmer climates and the north. Wooden house frame can be assembled at low temperatures.
Canadian construction experts state that these houses if updated, can serve about 150-200 years. Stability of frame houses is in line with their elasticity, so they are seismically resistant and can withstand even earthquakes (in Japan 75 % of the population uses such houses and place high buffer stake in the middle around which the rest of the house is constructed - the walls move with stakes but remains intact). On the other hand, frame house cannot withstand stronger windstorms and hurricanes which are common in North America. In Lithuania, garden houses are built by frame construction for several decades already. Residential frame houses are gaining popularity as well.
Thermal efficiency: airtightness is the most important factor for thin walls
In Lithuania, brick and concrete apartment houses are conventional, which resulted in a misconception according to which if a house has thin walls, then it retains heat poorly. The average wall thickness of a wood frame house is 20 cm but even during the cold, without heating of the premises, the temperature decreases only 2-3 °С per day. It is not difficult to heat frame houses and to maintain the desired temperature mode. In this case is airtightness of the frame house is very important because heat loss depends on it.
The heat disappears from indoor heating devices by ascending to the top which creates serious pressure near partitions - ceilings, windows and walls. Through smallest crack, the warm air is pulled outdoors, while at the same time, the at the lower part of the room air gets rarified and cold air is pulled in through the leaky floors, doors and windows and must be heated again. This energy loss can be reduced by increasing the thermal resistance of partitions. US company named „Architectural Energy Corporation“ conducted a research: heat loss through uninsulated building constructions was calculated. Later, the same constructions were coated with an impermeable and warm insulation material. The results showed that the heat savings is based on airtightness.
By increasing thermal resistance of especially tight insulation material layer by more than 100 % (by thickening the layer from 10 cm to 20 cm), heat savings reached only 3 %. more, so this investment is inefficient. It can be concluded from research results that it is much more efficient to invest into integrity assurance of home constructions, because even completely thin layer of airtight insulation material prevents a large portion of the indoor heat from escaping.
Insulation material must conduct steam that is insulated wet constructions do not rot or gather mold and easily dry out. Both vapors and air go through insulation material at about the same speed. However, the drying process of construction materials is relatively slow, so good enough air conductivity of insulation material can be so small that it can be attributed to the airtight materials. By selecting a sufficiently airtight insulation material, air circulation through the partitions can be significantly reduced along will the heating (winter) and cooling (summer) costs.
Frame house construction
Traditional brick, wood or stone wall building materials must perform multiple functions at the same time (to keep the structures, to isolate heat and sound), this determines certain construction conditions: to ensure the natural drying and shrinkage of the building, the wall thickness must be big enough, foundation must be massive, and construction time - relatively long. Construction technology of the frame houses allows separation of functions assigned to different materials - bearing, partition and insulation. Each element has its own task and the corresponding features: various materials ensure structure strength of minimal thickness, retains heat effectively, cuts off moisture and protects against noise.
Foundations may be monolithic or with poles but it is not necessary to build a solid foundation, which shortens the construction time and reduces the cost. Typically, frame houses are built in 1-2 floors. Such houses are very lightweight, have smaller dimensions, their interior finishing requires fewer materials. It is also one of the benefits, as opposed to the construction of panel houses - flexibility is the implementation of various architectural needs.
One of the potential drawbacks of such houses - acoustic properties, so special gaskets are mounted during construction, they act as sound insulation. Filling determines the sound insulation. Often the problems occur because of entablatures: if the two-storey house, people may begin to complain about audible sounds, such as steps on the second floor.
This problem is solved by choosing a sufficiently solid wooden overlay on which later concrete floor is cast. Even a five-stroey house can be installed body using the frame principle, but traditionally this construction is associated with 1-2-storey houses.
Frames are made from dried calibrated wood. Builders often prefer to use coniferous type of wood for construction due to its better properties. Spruce wood is elastic; pine wood is more fragile but modern technology allows to protect the wood properly from adverse environmental effects. Wood deforms over time but proper installation of construction, usually, prevents decoration from deformations.
Price of partially finished panel house, excluding foundation installation and painting works may amount to approximately 230 - 440€ per sq. m. and more. Frameworks can be installed within a few weeks. It is important to note that it is necessary to choose right weather conditions for construction of the frame house, because the wood of the structure mounted on the construction site may be affected by humidity and frost. If you decided to build a frame house, do not leave it to stand for a couple of years with no windows and doors, because it will not withstand it. So, it is necessary to pre-plan the construction works and raise sufficient funds.
Frame installation phases
Frame up to the roof consists of 3 parts - the lower beam, passing along the foundation, outer and middle struts and the crown. After consolidation of wall construction, roof construction is started.
Between the foundation and the bottom beam through width of the wall, the rubber gasket that prevents moisture and ensures tightness is laid throughout the entire perimeter.
Later, fixing of the frame (calibrated timber is more suitable) elements begins. Elements are arranged approximately at every 60 cm from each other. Frame materials relate to nails or screws. According to project requirements, in corners and other places thicker wood lumber is used.
Later, the crown is attached and the ceiling is mounted. Its thickness can vary from 1.95 to 2.45 meters depending on whether concrete floors will be cast and several partitions planned. If it is a single-storey house, it is necessary to consider the future construction of the roof.
If you decided to build a frame house, do not leave it to stand for a couple of years with no windows and doors, because its frame will be inevitably affected by poor weather conditions.
Although, various panels (plywood, wood particles, wood fiber, gypsum, OSB panels) can be used in the frame houses because it gives walls stiffness and stability. The choice of plate thickness should be made according to the frame: if it is wide, it is possible to use thinner plates.
Before attachment of the inner panels, the resulting cavity is filled with thermal insulation and insulating materials. The thermal insulation layer is formed from the mineral and rock wool. Then film that protects from water vapors (at this stage, the walls should be equipped with electrical installations) is spread. Wall is completed with already mentioned decorative panels, in some cases, they are combined. In such way, walls formed several layers of different materials will conduct less heat.
Later, the home's exterior is plastered or affixed finishing materials.
Wooden frame houses
Benefits
• Low construction weight (frame houses are 5-6 times lighter than brick houses).
• Relatively short construction time.
• Readily available materials.
• The ability to express architectural preferences (to construct a house of individual shape and internal planning) more easily.
• No need for large construction equipment.
• Internal communications (water, sewerage, heating) hidden inside walls.
• Easier to modernize.
• Good value for money.
• Eco-friendly, renewable materials.
Limitations
• Less resistance to windstorms and hurricanes.
• It is necessary to choose good weather conditions for construction because the wooden structure mounted on the site may be affected by humidity and frost.
• It is especially important to make the house airtight, otherwise, a lot of heat loss and the poor sound insulation may occur.
Commentary of a specialist
Valentinas Širvinskas, commercial director of wood houses building company "Rembilda”
"Before raising any arguments "for" or "against" any construction system of wooden or brick houses, first, it has to be noted what determines quality and value of the living environment (not just the house) throughout its entire life cycle. The wooden construction of individual housing sector is characterized by an extremely high level of efficiency. It is perfectly defined by the principle of "less is more". Perhaps, the artistic value of the building, energy efficiency or the market value of the land should not be put on the front lines of importance because health, longevity and adaptation are just as important. The whole picture must be appreciated. If we have in mind the aesthetics, tradition and scientific innovation and consider the environmental friendliness of the construction, then the advantages of wood construction can be clearly seen.
The problem is that in many countries, according to local building regulations, only the minimum quality requirements are set for this category of buildings and if the state does not additionally support the "green innovation", then problems on the citizens' self-determination and choice occur.
Of course, the inevitable happens - the modern science monitors and further attempts to copy the processes that take place in living nature and to apply them in various fields. Numerous evidence suggests the major upcoming changes in science and innovation. This inevitably touches individual construction also. Looking a bit into the future and trends it can be predicted that a natural selection will take place and more effective systems will gradually begin to dominate. Observing the development of the scenario, we would like to state that golden age of wooden construction and architecture is inevitably approaching."
Natural roofing
Recently, roofing ranges in very different ways - according to the needs and lifestyle of the customer. More popular are slates, corrugated fiber cement sheets without asbestos. Steel and copper roofing are also becoming popular. However, building their houses from renewable materials, people often begin to look for the natural roofing. Tiles are the most popular. They may be ceramic, terracotta or wooden - reminiscent of a few hundred years old architecture and roofs made in the past. Since ancient times, tiles covered pitched roofs of the wealthy townspeople who were proud to be able to afford them. Even today, high quality and environmental impact-resistant tiles decorate pitched roofs and are considered durable and aesthetically pleasing.
Another far less known material - slate. It is a natural substance, for which we must thank the natural processes that were happening for millions of years. For centuries, the slate is obtained in an environmentally responsible manner. It is extracted and processed without any additives. Slate was and is roof and wall material. Entire generations of architects and roofers create building style, artworks, tradition and culture from the slate material.
Reed and thatched roofs are becoming more and more acceptable in Lithuania. They can provide unmatched charm to residential houses, summer houses, gazeboes, saunas or any other building in the rural, urban or suburban area. Reeds and straw retain the heat longer and are durable (serve up to 50 years) but is susceptible to flame: if hit by fire it can instantly burn down the whole house. By the way, reeds and straw can be impregnated with chemicals to protect against fire. If you choose a natural roofing you should pay special attention to the protection from fire.
Alesia Paškevičienė
