- Why PVC is not liked in Europe
- What properties do wooden windows have?
- How wooden windows are made
- Wooden window construction
- What to look for when ordering wooden windows
Wooden windows are not the same for a long time. The introduction of innovative production technologies has eliminated most of their shortcomings. Now they can compete with plastic in terms of durability, practicality and functionality. At the same time, the “euro windows” are still beautiful and safe. Let’s take a look at the features of wooden window blocks in comparison with PVC structures.
Why PVC is not liked in Europe
Polyvinyl chloride. Not a very pretty and a little scary word, is it? This is the name of the now incredibly popular base synthetic polymer. This material has a number of outstanding performance properties, therefore it quickly found application in almost all industries, and especially in construction. PVC receives its specific characteristics due to a certain set of various additives. Plasticizers facilitate the processing of polyvinyl chloride, make it elastic, stabilizers prevent degradation during the production and operation of products, modifiers improve specific physical properties, fillers reduce cost, dyes allow the production of colored products.
For more than 80 years, polyvinyl chloride has been triumphantly walking the planet, but it is constantly reproached about the safety of PVC products for humans. PVC producers are fiercely fighting for their products, they are ready to prove their environmental friendliness by all means. A myriad of tests and tests have been carried out, many certificates have been received. But there are no completely safe additives for polyvinyl chloride..
Recently, a renowned manufacturer of plastic profiles announced that it is phasing out the extremely harmful lead and is switching to calcium-zinc stabilizers..
And this after almost forty years of history of making plastic with lead? How many years from now will they tell us the truth about calcium, cadmium, zinc? The Russian consumer, who is financially able to afford high-quality Euro windows, is at a crossroads, he is well acquainted with the creepy wooden products of the Soviet era, but something is alarming him in PVC windows too. Many are not ready to fully and completely trust official sources and even more aggressive advertising statements from sellers of plastic windows.
Naturally, we are not trying to invent a bicycle, but referring to the experience of Western European countries, especially since the manufacturers of plastic windows in their booklets are happy to provide the relevant statistics. When they say that in Germany the share of plastic structures is more than 50% of installed window systems – it’s true, but this percentage refers to the total mass of translucent structures. The windows of residential premises in the homeland of PVC are made of wood in 70% of cases, and their share is constantly growing – by 3-4% per year, naturally due to plastic. If we talk about the countries of Scandinavia, there generally more than 70% of all windows are wooden. The percentage of timber windows falls slightly in countries with small fluctuations in annual temperatures and scarce forest resources, such as Spain, Italy, France. The reality is that, despite the global financial crisis, Europeans prefer parquet, cotton and wood joinery to linoleum, synthetics and plastic windows, and the PVC window market is rapidly and confidently shifting towards Eastern Europe.
What properties do wooden windows have?
Wood is a pure, natural material that initially possesses excellent technological qualities: low thermal conductivity, good sound insulation, resistance to temperature influences, high strength. Unfortunately, wooden windows are afraid of moisture. Wood needs reliable multi-stage protection, including from insects, microorganisms, fungi. The production of translucent wood structures is a high-tech, long-term and expensive business..
Naturalness and beauty. Wooden windows are the embodiment of home warmth and comfort, the aesthetic characteristics of wood products remain unrivaled, despite quite successful attempts to copy its texture. Qualitatively made wooden windows can become a highlight, the core of the entire interior, in many ways determine its style. Even staunch supporters of PVC windows, being committed to the practicality and availability of plastics, will not argue with the exceptional attractiveness of natural material. Thanks to the ability to process wood manually or using digital equipment, manufacturers of wooden windows can offer the consumer products of a wide variety of non-standard shapes. In turn, the desire of designers and developers to use some kind of “special” plastic window in the interior is simply unrealizable due to the official brevity of the angular PVC profiles..
Strength. Any kind of wood consists of fibers oriented in a certain direction, which, with a competent approach, alternating their direction in glued beams, allows you to create very strong, durable, geometrically stable products. Compared to PVC windows, which are necessarily stabilized with a metal liner, they have a disproportionately lower coefficient of thermal expansion. At the moment, windows are most often made from pine, oak, larch, beech, cedar, fir, spruce, mahogany. Each type of wood has its own strength and durability indicators. But do not forget that the denser and stronger the material, the more thermal conductivity it has.
Insulating properties. Wood has natural porosity and contains air in capillaries. Therefore, with an equal thickness of the profiles, a wooden window keeps heat and dampens sound vibrations somewhat better than one made of multi-chamber plastic. On average, oak is 20-25% warmer than PVC, pine – 25-30%.
The need for protection and periodic care. The stumbling block for wooden windows is atmospheric humidity. Wood can easily absorb moisture from the air, which causes the fibers to swell – the product leads. The rapid loss of moisture causes cracking and deformation with consequent loss of insulation performance. It is due to the fact that it is necessary to take serious protective measures that the overall technological chain is so long, and the cost of wood products remains invariably high. Only multi-stage processing of wooden profiles with antiseptic impregnations, primers and paints and varnishes will provide the windows with practicality and durability. However, no matter how technologically advanced the coating is, it has its own service life, therefore, once every 3-4 years, sometimes more often, it is necessary to tint wooden window blocks, in particular, the lower horizontal parts of the folds that are most vulnerable to rain and ultraviolet radiation. This is why combo windows have appeared, as well as options with aluminum or plastic overlays over wood. In addition, every year of operation, the protective coating loses about 0.01 mm of thickness, which is why a wooden window should be periodically treated with special polishes, varnishes.
Sustainability. In fairness, we note that, despite the obvious safety of wooden windows, their production cannot be imagined without the use of a certain amount of “chemistry”. Fillers, primers, putties, paints, glazing compounds, antiseptic impregnations, glue for the manufacture of timber, butyl sealants for double-glazed windows – this is what PVC window manufacturers talk about when discussing the environmental safety of wooden window systems.
“Breathing” of wooden windows. Wood window manufacturers claim that their windows “breathe”. Some even say that through the micropores of wooden boxes there is an air exchange of such a volume that is able to provide ventilation of the room, preventing condensation from falling out. They are a little cunning. The doors of wooden windows have several sealing contours, the wood is treated with compounds that fill the pores – in other words, such structures are practically airtight. The air entering the room through the window will clearly not be enough for normal ventilation (GOST 24700-99 “Wooden window blocks with double-glazed windows”), condensation will appear. That is why serious companies persistently offer their customers wooden windows with installed ventilation valves, which were originally invented for PVC products..
High price. With all the advantages of wooden windows, their price is quite high compared to plastic ones. For example, a standard pine window block (1.45×1.8) already in the basic configuration will “pull” $ 600-800, any other wood species will increase this price by an order of magnitude. This largely explains why domestic consumers prefer to order plastic windows several times cheaper, which, moreover, “do not need to be painted”, “this is not a tree – it will not crack, it will not dry out”, “I put it on, wiped it with a rag and forgot”.
How wooden windows are made
The material and structure of the profile is the main thing that distinguishes wooden windows from PVC products. The production of a high-quality window profile from wood is a complicated, long and very labor-intensive business. It is not surprising that, as soon as the first samples of Euro-windows appeared in the post-Soviet space, the energetic owners of traditional “carpenters” quickly noticed their prospects and tried to establish appropriate production, but did not achieve success. Even now, many companies that assemble wooden windows work with a purchased profile..
In most cases, modern wooden windows are made from multi-layer glued beams. It is not unreasonably believed that it has greater strength, better resistance to temperature extremes, and less hygroscopicity compared with solid wood. Some manufacturers have mastered the technology of producing high-quality windows from solid northern pine, which is carefully selected and dried no less carefully. The raw materials intended for the production of timber are subjected to several rather complicated stages of preparation..
First of all, the wood goes through several stages of drying, the full cycle of which takes some time:
- natural drying,
- processing in the chamber – steaming and dry heating with alternating temperature indicators,
- normalization of temperature and achievement of moisture balance.
Drying is designed to remove internal stresses inside the wood, as well as eliminate the possibility of cracking during processing. Preparation of boards in drying chambers is carried out automatically, according to a given program for certain types of wood. The optimum moisture content of the raw material at the outlet ranges from 10-12%.
Further, the wood is rejected (optimized). Areas with knots, cracks, resin pockets, remnants of the core, wormholes, shells and spots are cut from the board. This is how small planks are obtained – plots, at the ends of which toothed spikes are milled. They are coated with water-repellent glue and spliced under pressure into one long board – lamella. The glued lamellas are kept in the press for some time, after drying they are planed (calibrated).
The next stage in the production of a profile is gluing the timber in thickness. The boards are glued together under a press, flat, while the inner layers are made of spliced lamellas, and the outer ones are mainly made of solid ones. As a rule, a three-layer timber is made, however, some companies use a technology with a large number of layers, and some lamellas can be glued to the sides of a three- or four-layer cake.
It is very important that the fibers of adjacent lamellas are directed in opposite directions. Only such glued laminated timber is considered to be of high quality and is able to ensure the stability of the geometric shapes of the product..
Then the wooden beam is milled on numerically controlled equipment, as a result of which a window profile with a very complex section is obtained. For the manufacture of windows with exclusive, non-standard shapes, an individual approach may be required, “handmade”.
Further, the process of making a wooden window is significantly accelerated. The frame is assembled, sanded, treated with impregnation (under pressure or vacuum), primed, painted. After the end of the painting work, double-glazed windows and seals are installed, fittings are mounted, sashes are hung.
Wooden window construction
Modern wooden windows are structurally very similar to plastic products. For their operation, the same fittings are used, which allows not only pivoting, but also tilt, tilt-and-turn opening of single doors. They also have multiple sealing circuits. For the glazing of wooden windows, not only sheet glass is used, but also various types of double-glazed windows, including special, energy-saving ones. The main difference between wooden windows is that they can have several design schemes, depending on the number and type of sashes. Note that some constructions are historically associated with a certain country, which was the reason for their “popular” classification by nationality.
Single sash windows. This is the so-called European type, “Euro-window”, German window. In fact, this is a direct analogue of plastic windows, with the only difference that the profile is made of glued wooden beams. With a profile width of 68 millimeters and more, a double-glazed unit of any type from 36 to 44 mm is installed in them. The design of the vestibule allows using two or three sealing contours for euro windows, modern fittings make it possible to control all operations with the sash only with a handle. The hardware itself for such wooden windows is produced by the same companies that operate on the PVC products market: Roto, Maco, Siegenia-Aubi … Naturally, the consumer becomes available to such options as winter slot ventilation, step opening, burglary protection and others. Single-leaf wooden windows are currently the most common in our country.
Windows with split sashes are also called “Finnish”. Such a window unit has a large frame width, about 120-180 mm. On the outer and inner sides of the box, sashes independent of each other are hung, as on Soviet windows. Sheet glass is inserted into the outer sash, which serves as a kind of buffer against the effects of various environmental factors, and the inner sash is supplied with a single-chamber, often energy-saving glass unit. Interestingly, the outer glass seal is not airtight, which prevents condensation from falling on it – this is just a so-called “boot”. Fittings operating in windows with separate sashes allow only rotary opening, therefore ventilation is carried out using a window or a sash opening limiter. Due to the two-chamber design, such windows have excellent insulating characteristics, the considerable width of the box prevents the slope from freezing. Inside the Finnish window, between the sashes spaced at a great distance, sun blinds are installed, sometimes even removable grilles.
Double-sash windows are supplied to us mainly from Sweden. They also have a double frame design. Their main difference from windows with separate sashes is that the inner sashes of such window blocks are connected to the outer ones by means of sliding connecting elements. The inner sash has tilt-and-turn locking hardware controlled by a single handle. Therefore, designs with paired sashes are also called “euro windows”.
Which design of a wooden window is better is difficult to say unequivocally, each of them has its own pros and cons. For example, a double-glazed unit of a single-leaf window and a glazing of double-leaf windows (sheet glass plus a glass unit) have approximately the same insulating characteristics. The wooden frame of double-leaf windows is warmer due to the large width, but at the same time, you have to look after not two, but four planes; the separate design does not have the tilt-opening function that is loved by many. Of course, “Scandinavian” windows are more expensive than “European” ones, but if you compare blocks with similar sound and heat insulation, the difference will not be very significant, especially when the first ones are made in Russia, and the second ones are made abroad..
What to look for when ordering wooden windows
Foreign manufacturers of wooden windows are firmly entrenched in the Russian market. They are constantly working to improve the quality of wooden translucent structures, to reduce their cost. Every year we are offered fresh constructive developments, new protective compounds and types of profiles. Western firms carry out a full cycle of work from timber harvesting to the manufacture of double-glazed windows; they have large high-tech factories. Our manufacturers work according to European technologies, on imported equipment, many of them buy profiles and double-glazed windows on the side, often abroad..
Imported windows are about one and a half to two times more expensive than Russian ones.
From measurement to delivery, you will have to wait up to three months, while domestic companies usually complete an order within 3-8 weeks.
The guarantee is provided in most cases, a comprehensive one – for a profile, a double-glazed window, a protective coating, and fittings. Naturally, the window must be installed by the manufacturer’s specialists. Russian firms usually give a 3-year warranty for their products, foreign ones – 5 years.
Windows made of oak are about 2 times more expensive than pine; larch – 1.5 times.
Wooden window blocks made of timber with spliced outer lamellas will be cheaper on average by 15% than with solid ones.
You can save money by ordering a profile in which the outer layers are made of expensive wood, for example oak, and the inner layers are made of pine. There are options for finishing the profile with valuable wood veneer.
Windows of standard sizes are also somewhat cheaper than custom-made windows.
The longer the production time, the lower the cost of the window – this is how manufacturers regulate the flow of orders. But for urgency you will need to pay up to 20%.
Blocks with twin and split leaves are 15-25% more expensive than single-leaf units.
Often, from the window manufacturer, you can order related products corresponding to the frames in color and texture: window sills, slopes, platbands.
It is quite obvious that modern wooden windows will find their place in our country as well, they will be more practical and more accessible from year to year. The plastic boom will end sooner or later, and the share of timber windows will begin to grow, especially since the Russian climate is quite harsh, while we have decent forest reserves, and behind us we have centuries-old traditions of wooden construction.