CLT

CLT
THE TECHNOLOGY

CLT is currently the only non-lightweight construction material that can be used to build truly sustainable and environmentally friendly buildings quickly, cleanly and with high accuracy. CLT construction is much faster, cheaper and with a comparable price, it has a lower ecological footprint with 70% than conventional construction technologies.

WE ARE BUILDING HERITAGE.

THE TECHNOLOGY

Two thirds of air pollution is caused by steel and cement production. In other words, the construction industry. All this in a society where we want everything to be done quickly, cost-effectively, and accurately, but where pollution can no longer be ignored.

Thanks to forward-thinking engineers, the solution to these problems is already here. Known today as CLT (cross laminated timber), the construction technology was introduced in Europe in the early 1990s. Today, the technology is spreading at an incredible pace in the United States and other countries.

This use of materials has proven effective for many types of buildings, from low-rise to high-rise. Compared to concrete and steel, it is a much more cost-effective, dynamic, durable, and sustainable method.

Could this be the building technology of the future? Well, yes!

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WHY DO WE
RECOMMEND CLT TO OUR CLIENTS?

10% larger net floor area

Its strength is denoted by C24 in the same way as concrete, therefore very slender walls are sufficient, which means that the structure takes up less space for installation.

The walls are straight, and the corners are precisely 90 degrees.

The technology is very accurate. The walls and slabs fit exactly into place. Using the BIM (Building Information Model) system, the digital drawing is implemented with millimetre accuracy on the construction site.

3x faster construction time.

CLT panels can be prefabricated and then assembled on site. This speeds up the construction process and reduces the amount of waste generated. And time is money!

THIS IS NOT A LIGHTWEIGHT HOUSE!

It has heat storage capacity. So, it doesn't cool down as quickly when you turn the heating off. It is also heavier and more stable, but 5x lighter than concrete!

Its fire resistance is staggering.

It can be more fire resistant than some untreated steel, when exposed to fire its outer layer turns into insulating charcoal that can keep a fire at a lower flame for 30-120 minutes.

Solid wood walls.

It can be easily fixed to the wall with simple wood screws and can also be easily covered with plasterboard, painted, wallpapered, and freely decorated.

It can control the humidity!

No thermal bridges in the structure, eliminating mold growth in the building. CLT is a breathable material, acting as a variable vapor permeable layer. It purifies the air and removes bacteria. Wood is a natural humidity regulator, absorbing and releasing moisture according to the prevailing conditions, thus regulating indoor air quality. Wood therefore also acts as a humidity stabilizer, improving indoor conditions and reducing asthma and respiratory diseases.

PRODUCTION
-How is the CLT Panel made?

It is made from planed, dried spruce with transverse layers (3-5-7-9 layers)

Which are then pressed together under high pressure with an environmentally friendly adhesive that is not harmful to health (formaldehyde-free)

The size of the resulting panels is limited only by transportability. The typical transport panel size is 2.95 x 13.50 m, but the maximum production panel size is up to 3.45 x 16.00 m.

By gluing the wood layers at right angles, the panel can achieve better structural rigidity in both directions.

CLT panels are available in different thicknesses to suit structural needs.

Load-bearing walls are usually 10 cm thick (3-5 layers) and partition walls are 6-8 cm thick

These panels are mainly made of spruce but may also contain pine or larch and a few percent hardwood.

The timber is sanded, dried, and cut to shape. Drying is a very important step, because it removes moisture and prevents the wood from cracking and changing size.

The treated boards are then stacked, referred to as lamellas, so that these lamellas are perpendicular to each other.

The lamellas are glued together with an environmentally friendly adhesive and then the elements are reinforced by hydraulic pressing.

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The vast majority of CLT panels are manufactured for a specific
application, with a prescribed size, shape, appearance, and
machined sections (e.g. recesses, holes, grooves).

The manufacturing technology results in a high degree of precision, which will facilitate subsequent on-site assembly.

On-site assembly is faster, cleaner, safer,
and last but not least more cost-effective.

STATICS

An individual structural design is made for each building, considering local wind, earthquake and other stresses. In this way, each building is statically certified to have adequate stability for the given conditions.

CLT load-bearing structures are designed according to Eurocode 5. CLT's strong transverse design provides exceptional structural stability. It is five times lighter than concrete, yet has the same strength, and as a multi-layered wall panel it can be cantilevered in two directions and a smaller slab thickness is sufficient for the same span. Its light weight allows lower foundation costs, easier transportation, and faster on-site work. Unlike concrete, CLT structures can be installed in any season, even in winter. With proper planning, up to 1,300 square meters per day can be installed, significantly shortening the construction schedule. Their stability and rigidity allow them to withstand lateral loads (earthquakes) effectively. They are extremely dimensionally stable: swelling, shrinkage and warping are negligible.

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HEAT TECHNOLOGY

The term 'building insulation' covers all the means of keeping the energy required to heat and cool a building to the minimum. During the design phase, we develop the appropriate layering system, taking into account the customer's needs.

The thermal conductivity of wood is essentially determined by its mass, density, and water content. For CLT structures, this value is λ = 0.13 W/mK, while for a conventional Porotherm 30 N+F it is 0.16 W/mK, i.e. wood performs better than conventional masonry. The CLT structure has a slightly lower thermal conductivity than concrete or ceramic masonry, but all traditional insulation technologies can be applied here, too.

SURFACE

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In each case, it is up to the client to decide how much wood surface to show. This versatile natural material, whatever the type of wood, is extremely versatile and immediately creates a pleasant atmosphere in the home.

We can choose to let the raw wood colour dominate the space, but it can be aesthetically pleasing to leave only one wall surface free in the living room or bedroom, with CLT wall cladding in the rest of the space.

Raw, rustic, velvety or surface-treated wood can create a welcoming, natural atmosphere. No matter what style you prefer your home to be, you are always guaranteed a warm and welcoming atmosphere.

Three quality classes are distinguished:

1

Industrial, no visible surface:

basic quality, warps, colour variations, texture defects are allowed. For walls clad on both sides and for non-visible structural elements where there are no visual requirements.

2

Industrial visible surface:

higher quality than the previous one, no warping, colour variations and texture defects are very minimal or non-existent. Ceilings and elements in less exposed locations are made of this type.

3

Transparent surface:

the highest quality class. Consists of glued laminates of a wood species with a uniform grain and texture appearance, free of warping and cracking. Spruce, larch, pine, silver fir, and various hardwoods (beech, oak, ash, etc.) are available on request.

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ACOUSTICS

The definition of acoustic requirements and solutions is of paramount importance at the design stage.

Many people have had bad experiences with old timber-framed or lightweight houses. The most common complaint is about acoustics. The floor is banging and everything can be heard through the walls. However, CLT, or in other words mass timber construction, should not be confused with timber-framed houses and other lightweight construction technologies. For example, the sound insulation of a CLT wall is better than of a brick wall of the same thickness. Compliance with standard sound insulation requirements can be verified by calculation, so a CLT frame is no noisier than a brick or reinforced concrete building.

In the case of CLT structures, the requirements can be met by the structures alone (by varying the structural thickness) or in combination with additional insulation materials (façade ply, interior plasterboard structures). If required, the vibration and sound insulation can be enhanced by the installation of special tapes at the joints of the panel elements. 9.

FIELDS OF
APPLICATION

The technology is used in the construction of single-family houses, multi-story residential buildings, public buildings, administrative buildings, commercial and industrial buildings, new constructions, extensions, and bridges.

Sizing and design are carried out in accordance with structural, building physics and legal requirements, and solid cross laminated timber panels are made to order, tailored to the specific projects.

ENVIRONMENTALLY FRIENDLY TECHNOLOGY

An important consideration in our work is that CLT frames are built with the least possible environmental impact.

The waste generated during the construction of a single-family house does not fill the boot of a car.

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More importantly, the greenhouse gas emissions associated with CLT construction are far below those of any other conventional building material. For our buildings, our designers calculate the carbon footprint and give it a rating on a scale from A+ to G. Traditional reinforced concrete and brick houses are barely at class D, but are more likely to be class E-G. In contrast, a CLT building will generally have an outstanding A-A+ score

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In contrast to the materials responsible for air pollution (steel and cement production), the production of CLT imposes a negative burden on air pollution.

How is this possible? As the wood grows, it absorbs CO2, which is then stored in the walls. An average tree absorbs about 22 kg of CO2 per year, as well as other pollutant gases from the atmosphere, including nitrogen oxides, ammonia, and sulfur dioxide. These gases remain part of the tree until it decomposes, so they do not harm the environment. In this way, we can help protect our environment.

Do we have to cut down many trees? Our partners (timber companies) work exclusively with wood from sustainable forestry. This is certified by the PEFC certification of each panel. Sustainable forest management means managing forests in the present in such a way that the benefits - environmental and economic - are passed on to future generations. So instead of felling, only 1 to 5% of the forest is cut each year and the cut trees are immediately replaced.

A house built from CLT is somewhat similar to an older log house and takes us back to our roots. Being in touch with nature has physiological, spiritual, and social benefits. A design approach that integrates this connection into interior spaces can help improve people's health, productivity, and well-being.