Prefabricated houses: prices. Pre-fabricated wooden houses: why is it recommended to build a prefabricated wooden house today? Here we explain the advantages of building wooden or prefabricated houses.

Let’s start by differentiating the image of a prefabricated wooden building from the habitable and non-habitable wooden houses that we can buy in the DIY shopping centers. Actually, prefabricated houses in Italy are often used as garden ornaments, storage for toys or garden tools; in some other countries they are spreading as small housing units, prefabricated studios, sometimes mobile. However, prefabricated wooden villas are a different thing, even though from an aesthetic point of view they do not differ in any way from those prefabricated in cement and masonry or the traditional brick buildings. Why did ELITE ECOBUILDING decide to build wooden houses and why are the construction companiesincreasinglybuilding wooden houses? The reasons are many: this type of construction fits in the field of sustainable building, eco-sustainable houses, earthquake-proof houses, climate houses, wolf haus, etc.

Earthquake-proof prefabricated house

Prefabricated houses: prices, incentives and eco-sustainability

The market of prefabricated wooden houses has been growing for the past ten to fifteen years, but its development has been very slow due to several factors: prejudice, Italian tradition linked to building with cement or bricks, often higher prices or difficulties to find providers.

How many times have we wondered but how much does a prefabricated house cost? How much does a wooden house cost?

Before analyzing the actual costs of these construction methods, it is very important to understand what are the advantages and incentive opportunities that revolve around wood prefabrication. When we talk about green houses, eco-sustainable houses, energy efficiency and the related government incentives, we are certainly talking indirectly about wooden constructions. Due to the characteristics of wood, we enter into another area of ​​opportunities and incentives, those concerning the interventions of anti-seismic requalification.

Antiseismic prefabricated house – Italian Incentives

Due to the characteristics of wood, we enter another area of ​​opportunities and incentives, those concerning the interventions of anti-seismic requalification. Many do not know that since a couple of months it has been possible to deduct from 75% to 85% up to a maximum of 96 thousand euros in 5 years for seismic interventions in the Seismic areas 1, 2 and 3, for both restructuring and rebuilding, for both individuals and companies!

Would you like to know more? Discover the earthquake bonus 2019

 

Environmental issue: green building and passive houses

CEMENT BRICK		WOOD	SAVINGS	CASACLIMA
Conventional building Italian (ENEA data) 200sqm of living space	energy consumption for heating 175 KWh/mq. A	< 70 KWh/mq. A	60%	C
	energy consumption for hot water production 25 KWh/mq. A	25 KWh/mq. A	0	C
	energy consumption for lighting and kitchen 20 KWh/mq. A	20 KWh/mq. A	0	C
	overall energy consumption 220 KWh/mq. A	115 KWh/mq. A	48%	C
Low Energy Building 180sqm of living space	energy consumption for heating 59 KWh/mq. A	< 30 KWh/mq. A	49%	A
	energy consumption for hot water production 16 KWh/mq. A	16 KWh/mq. A	0	A
	energy consumption for lighting and kitchen 20 KWh/mq. A	20 KWh/mq. A	0	A
	overall energy consumption 86 KWh/mq. A	57 KWh/mq. A	51%	A
Passive Building 180sqm of living space	energy consumption for heating 15 KWh/mq. A	< 10 KWh/mq. A	33%	ORO
	energy consumption for hot water production 11 KWh/mq. A	11 KWh/mq. A	0	ORO
	energy consumption for lighting and kitchen 16 KWh/mq. A	16 KWh/mq. A	0	ORO
	overall energy consumption 42 KWh/mq. A	36 KWh/mq. A	14%	ORO

It is now clear that almost every aspect of human life in the coming years will have to take the environmental issue into consideration; this is unavoidable. Therefore it is highly recommended for those who build or buy a house to pay close attention to these aspects, regardless of what construction method they choose. Prefabricated wooden construction is recommended, since this kind of houses has the best features, in relation to quality and price andconsidering the low environmental impact. This construction method can increase, enhance and optimize the energy yield from renewable sources, thanks to careful design, exposure to the sun, the provision of openings and the use of high-performance and environmentally friendly materials.It succeeds to easily obtain the annual energy requirement without exceeding 15 kWh per square meter. It is also necessary to pay close attention to the entire life of the building product: from the procurement of raw materials to the production of materials, to the disposal of goods, to the recovery and recyclability of materials; combining the needs, the building evolution, the respect for the environment, the health of territory and human beings, the wooden structures with highly preforming materials as hemp, straw and clay, can really bring to high levels of environmental sustainability in your home or building.

It is a mistake to believe that today’s environmentalism is a matter of trend, inflated or exaggerated by the media. There are increasignly stingent rules on these aspects and sooner or later everyone will have to comply to them. The European Directive 2010/31 / EU sets that by 31 December 2020 all new buildings are almost zero-energy buildings, ZEB (Zero Energy Building). ZEBs are residential or commercial buildings that drastically reduce their energy needs by adopting a smart design, using plants that produce energy from renewable sources (such as solar and geothermal energ), constructing an efficient envelope, and optimizing thermal savings. Therefore, a “Zero Energy Building” is a building that meets all its energy needs through energy sources  that are available locally, at low cost, non-polluting and renewable. In Italy the directive was implemented through a decree amending Legislative Decree 192/2005; its art. 4-bis establishes that from 31 December 2018 all new buildings used or owned by the Public Administration must be designed and built as almost zero-energy buildings.

As of  1 January 2021, the aforementioned provision will be extended to all new buildings, which is why ELITE ECOBUILDING proposes the construction of prefabricated wooden houses: in terms of ZEB features, anti seismicity, comfort and price, this construction method is unrivaled.

Prefabricated houses: turnkey prices

Here are the costs: our company is able to supply prefabricated wooden houses starting from 1000 € / square meter, but starting from a very simple base. Obviously the prices vary considerably depending on the type of finishes and materials used, the systems used for the management of utilities, such as the design of natural and / or mechanical ventilation systems, the installation of a home automation system for the intelligent management of systems and related consumption. Today’s wooden houses are structures of the highest technical level, with strict controls in terms of certifications, and ahve to comply with very stringent construction indications: from the systems to the thicknesses of the structures or coatings, from the energy supply to the heating management , including windows. However, prices can vary greatly depending on the brands selected, the type of materials used in compliance with the technical characteristics indicated by the certification protocols. In general, the price of a prefabricated wooden construction usually varies between € 1700 / sq m and 2500 € / sq m turnkey, including the foundation, doors and windows and systems.

However, these prices do not apply to renovations or recovery plans, where the price varies according to the demolitions or restorations that are made. Obviously the prices shown do not include the costs related to the design, urbanization charges, administrative practices and property of the fund that must be quantified separately (together with the statutory VAT, which in the case of a first home is 4%).

Prefabricated houses : PROs and CONs

Based on our experience, the advantages of prefabricated houses are economic and time savings. Houses built on site have a higher cost, but the customer can still apply small non-structural changes, such as the partition walls, the position of the systems, the choice of windows and floors; therefore, there is less concern about having to decide all details in the design phase. A further advantage of prefabricated houses is the reduced and fixed timing compared to other construction methods.

 

ELITE ECOBUILDING is specializing in this sector because it is convinced that in the coming years we will see a real revolution in the Italian, European and world economic systems, with an impact on housing solutions, transport systems, energy sources and management systems in our homes. Policies have been and will be put in place to encourage companies and consumers to favor eco-sustainability. Incentives already exisst for the use of specific doors and windows, energy restructuring, and a new system of “energy income” is currently tested in Puglia, Sardinia and Lombardy, where a fund has been set up to purchase photovoltaic systems and make them available for lower-income families. The electricity produced by solar panels will be consumed by families while the incentive for green kilowatt hours will feed the fund. The VAT adapted based on the type of investment is a measure already under discussion.

The Green New Deal is coming!

Do wooden houses resist fire?

Many would think that the wooden houses are less resistant than those in reinforced concrete, in case of fire. Well, it is not so, but exactly the opposit! Thanks to a natural property, the wood it extremely resistant to fire: this property is called carbonation. In fact, when the flame comes into contact with wood, the flame begins to burn the outer part of the wood and begins to char. Precisely, the charred surface acts as a protective barrier with respect to the innermost part, preventing oxygen from penetrating, thus preventing the burning of the innermost layers that resist the flames for much longer.

To express this property of wood in a technical way, the rate of penetration of the carbonation is measured by the time taken by the fire to pass the carbonized protective barrier. Obviously not all woods resist in the same way: lamellar fir, for example, burns at a speed of 0.7 mm / min; solid fir burns at a speed of  0.9 mm / min. To measure these properties the best known acronym is REI (Resistance Entrenir Isolement) always followed by a number of digits which express the time, in minutes, during which the three properties are guaranteed: eg. REI 30, REI 60 or REI 120.

Why do we say that a wooden structure is more resistant to fire than a concrete or brick structure? Thanks to these characteristics, the structural elements in wood, exposed to fire, are only slightly deformed and the longer times of deterioration allow the fire brigade to intervene, being most of the structure intact. On the other hand, the iron bars that are inside the pillars soak in case of high temperatures and lead to serious damages to the structure and in many cases to a violent and unexpected collapse.

Fire resistant wall layers

Stabilized plaster kit – 12.5 mm

1. Vapor barrier
2. Bearing structure – 145 mm
3. Thermo / acoustic insulation in mineral wool -150 mm
4. Wood panels – 21 mm
5. Plastered thermal coat – 68 mm

Polystyrene panels – 60 mm

Background plaster with reinforcement mesh – 3 mm

Premixed water-repellent final plaster – 5 mm

Masonry Prefab Houses

In central Europe, especially in Germany, this type of construction is widespread, but in Italy it is mainly used in the industrial and commercial sectors. We often see gigantic cubes that house large shopping centers, industrial warehouses or companies. This method is not widespread for residential use, because at the same cost traditional masonry or wooden prefabrication is worthwhile in Italy. Choosing the prefabrication in masonry for your home entails pros and cons: the cons can certainly be linked to the lower eco-sustainability due to the production of the construction components, the transport, and the difficult use in buildings with irregular shapes. For the construction of individual dwellings, the prefabrication in reinforced concrete or masonry allows very few margins of modification once the executive projects have been defined, and even in the future it will be difficult to make changes without affecting the structural strength of the building. Being very heavy structures, it is necessary to build thick concrete slabs on carefully selected grounds. Furthermore the thermal, seismic and energy performances are reduced compared to buildings in wood. On the other hand, the cost the time, especially for large buildings with homogeneous forms, are considerably reduced. If you want to build a prefabricated house, we recommend taking into consideration the different constructive opportunities.

Interior prefabricated houses

One of the most widespread criticisms against wooden prefabricated houses is about their durability or vulnerability to masonry. Many of these criticisms are groundless, because very often the wooden parts are covered and protected by thick layers of plasterboard, plaster, coat and the different layers that make up the house, making them safe. Furthermore, the wood is treated in such a way as to be more resistant to external agents, such as water, wind or humidity.

The interiors of a prefabricated wooden house can be exactly the same as any other house, with the possibility of modifying the layout of internal partitions when desired, which causes less problems due to the low production of dust, elements of rejection or invasiveness in the structure. If there is a water leak in a wooden house, will there be greater risk of deterioration? No, because as said before the wood is treated with water-repellent materials, which isolate it at the surface level; in any case, the deterioration is absolutely not greater than in a reinforced concrete and masonry structure.