​Wood products within a room have been shown to improve indoor air quality by moderating humidity. This effect occurs due to wood absorbing and releasing moisture in order to maintain equilibrium with the surrounding air, known as the equilibrium moisture content. Wood therefore absorbs moisture from the air in humid conditions and releases moisture in dry conditions.

• . (reThink Wood, 2014).
• . (Forest Products Laboratory (U.S.), 1998)

The ability of wood to moderate humidity is a particularly important effect in workplaces. This is because productivity has been demonstrated to be reduced by an average of 12% in offices where staff are dissatisfied with the quality of the air.

• ​​Bergs, J. Effect of healthy workplaces on well-being and productivity of office workers. in (2002).​

​The positive views of wood continue even when compared to other material types (Table 2). Wood was viewed as the material that creates a natural look and feel, warm and cosy environments, is visually appealing and is nice to touch by nine out of ten people, and as being the most environmentally friendly by seven out of ten people. By comparison the second most popular material, brick, received an average of 34% less positive feedback. Plastic was seen as the ​cheapest material but it also scored lowest in four out of five categories related to creating pleasant surroundings and being environmentally friendly.

​​These survey results provide support to the empirical evidence discussed above. Even though many people don’t understand the health and wellbeing benefits of wood they instinctively react to the feelings of warmth and comfort it creates and its natural look and feel. An increasing body of research is beginning to show that being surrounded by wood at home, work or school has positive effects on the body, the brain and the environment. 

Previously, we saw that the studies examining the effects of wooden rooms and furnishings clearly demonstrate that the presence of wood has positive physiological effects, lowering blood pressure, heart rate and stress responses when compared to other material types. These physiological responses are specifically controlled by the sympathetic nervous system (SNS). SNS activation occurs when the body prepares itself for stress, increasing blood pressure and heart rate, whilst inhibiting digestion, recovery and the immune system in order to deal with any immediate threats it perceives. Long term exposure to environments that induce stress can trigger serious health consequences, including obesity, type 2 diabetes and related cardiometabolic complications.

​The behaviours and health status of 44 elderly Japanese residents using wooden tables, chairs and tableware at a care home were examined and compared to residents using plastic products. The results indicated that the use of wooden products increased the number of interactions between individuals (i.e. more talkative and more willing to engage with one another), improved emotional state and expanded self-expression in a positive way.
​

• Anme, T. Behaviour Changes in Older Persons Caused by Using Wood Products in Assisted Living. 2, 106–109 (2012).

A Canadian study has demonstrated that the colours and texture of wood elicit feelings of ‘warmth’, ‘comfort’ and ‘relaxation’ in people, all emotions that have been shown to reduce stress, anxiety and recovery times in hospital by studies examining the influences of music, plants and therapeutic massage.
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• Rice, J., Kozak, R., Meitner, M. J. & Cohen, D. H. Appearance of Wood Products and Psychological Well-Being. 38, 644–659 (2006).
• Bolwerk, C. A. L. Effects of relaxing music on state anxiety in myocardial infarction patients. 13, 63–72 (1990).
• McCaffrey, R. & Locsin, R. The effect of music listening on acute confusion and delirium in elders undergoing elective hip and knee surgery. 13, 91–96 (2004).
• Park, S.-H. & Mattson, R. H. Therapeutic influences of plants in hospital rooms on surgical recovery. 44, 102–105 (2009)
• ​Post-White, J. Therapeutic massage and healing touch improve symptons in cancer. 2, 332–344 (2003).

A study in New Zealand presented 69 adults with images of 10 modern corporate interiors, chosen from recently published books showcasing contemporary design. Five of the interiors featured wood significantly, whilst the other five featured no wood at all. Participants were asked to ‘identify the organisation you would most like to work for and least like to work for’, followed by selecting three adjectives from a list of to indicate their first impressions of each organisation. The presence of wood products within a corporate environment drastically influenced first impressions, with study subjects significantly more likely to want to work for organisations that featured wooden furnishings. Offices with wooden interiors also conveyed feelings of innovation, energy and comfort, whilst offices without wood conveyed feelings of being impersonal and uncomfortable.

• ​Ball, R. D., Killerby, S. K. & Ridoutt, B. G. First impressions of organisations and the qualities connoted by wood in interior design. 5, 30–35 (2002). 

​The positive psychological outcomes of people interacting with wooden products could have significant economic impacts. This is because studies have shown that social interactions that lead to opportunities for self-expression in old people reduces the risk of dementia, a disease that currently costs North America billions every year and affects 44+ million people worldwide. Shortening hospital stays through reduced recovery times will also reduce costs to the medical system, whilst improved first impressions of organisations will attract business to the North American markets.
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• Dementia and memory loss statistics. (2014). at ​https://fightdementia.org. au/about-dementia-and-memory-loss/statistics

The health and wellbeing benefits associated with spending time outside in nature are well known and have been studied extensively by the scientific community and reported by Planet Ark.

These known benefits include:
• Increased happiness and self-esteem levels
• Increased cognitive abilities
• Decreased stress response, blood pressure, pulse rates and cholesterol levels

However, increasing urbanization rates mean that people have less access to nature in their daily lives and Americans on average now spend about 90% of their time indoors. This coincides with reports of increasing levels of obesity and many experiencing a mental health condition within their lifetime. As it is not always possible to increase our time spent outside, particularly in areas like workplaces, schools and hospitals, understanding how to incorporate the physiological and psychological benefits of nature into our indoor environments is an increasingly important area of research.

Studies have demonstrated that simply having a view of nature from a window can have significant positive effects, such as shorter postoperative hospital stays, induced feelings of relaxation in patients at rehabilitation centres and improved comfort levels of employees in offices. Not surprisingly, the presence of indoor plants has also been shown to have benefits, such as improved cognitive functioning in office environments, increased tolerance of pain in hospitals, lowered blood pressure and heart rates.

Evidence-based design (EBD) is an area of study that focuses on incorporating the results of empirical research into the quality of the built environment. Originating from the field of environmental psychology, EBD works on the notion that the design of the built environment fundamentally impacts the people within it. Of particular interest are designs of physical features that can lead to stress-reduction, productivity and general wellbeing. Since evidence shows viewing nature in both outdoor and indoor settings has health and wellbeing benefits for people, it is logical to examine whether wood, a natural material, produces similar effects.

​When Dr. Thoma's children reached schooling age, he had to quit the forester's position and move with his family to Salzburg, a more civilized area. Two weeks after moving into their new apartment, the children began to cough consistently. Over time, their coughing became so intense that it created a threat of suffocation. 

After many visits to the doctors, it turned out that the children were allergic to particle boards that the furniture and the floors in the new apartment were made of. This surprised Dr. Thoma, as particle boards were made from wood.  It wasn’t the wood, said the doctor, but the chemicals seeping out of them. The only solution was cortisone therapy. A leaflet revealed that cortisone administered to children under the age of 20 would destroy their kidneys.

​Luckily, Dr. Thoma's grandfather, a carpenter already in his 80’s at that time, had a different yet simple solution. Dr. Thoma sent the children with their mother away for the holidays, and together with his grandfather, the two replaced the particle board walls and furniture with simple and handmade solid wood. When the children came back and after a short period of time, all symptoms of their allergy disappeared.

THE ETERNALLY DUSTY STAIRWAY

Think about the static when you pull a synthetic jumper over your head, or how synthetic carpets get charged just by walking on them. And of course, it's followed by an electric shock when reaching for the doorknob - the corresponding discharge. Electrostatic charge is caused by dry and heated air moving past non-conductive synthetic surfaces. The resulting load is larger if the surface is less conductive. You rarely experience this with natural materials like pure wool or linen. Electrostatic charge is caused by dry and heated air moving past non-conductive synthetic surfaces. The resulting load is larger if the surface is less conductive. You rarely experience this with natural materials like pure wool or linen.

'Building biologists' make sure that there are as few electrostatic chargeable surfaces as possible in living areas.

The human body in itself naturally has a weak electric shield surrounding it. This weak electric field repels dust, dirt particles and bacteria, etc. Rooms with a strong electromagnetic charge disturb this natural protective field and those who are sensitive can experience allergies, inflamed mucus membranes, colds, headaches, etc. In Europe, this is called the 'sick building syndrome'.

Another disadvantage of statically charged surfaces is the tendency to attract dust and dirt, like the surface of a TVs or stereo. But this problem is easy to solve - just make sure you have as much natural and untreated wood in your home as possible. If you want to treat wooden surfaces, use only natural bees wax or resins.

Floors, walls and ceilings made of untreated wood will not affect the natural occurring electromagnetic fields in your home negatively. This characteristic is one of the reasons an old alpine cabin feels so much more comfortable than an apartment with painted surfaces.

Here is a short story of a young couple in our neighbourhood: a couple of years ago, they experienced an interesting phenomenon in an unexpectedly. When their home was built, the contractor installed a floor made of ash wood in the entry area of their house. The surface of this floor was then treated with natural resin and bees wax. The staircase in the foyer connected the rest of the house with the entry area and was built by another carpenter who laquered the stairs with a commercial water-based product.

"Horrible", the wife complained. These stairs act like a dust magnet, it seems they attract all the dust from the whole house. The waxed and oiled floors in the other rooms do not, just the staircase was forever covered in a layer of dust. The wife would mop it three times a day and complain about it many times. Her husband finally promised to take off the varnish and oil as he had done with the other floors. There was no doubt that she would insist on him doing what he promised to do.

WHAT IS MORE HYGIENIC?

An American study called "Plastic and Wooden Cutting Boards" by Dean Oliver, Ph. D. in his research of salmonella and kitchen cutting boards showed drastic results. Salmonella actually dies after a few minutes on a natural, untreated woodcutting board, whereas plastic cutting boards encourage salmonella to thrive and increase in population. Think about laminated kitchen counters and cutting boards which many people think are more hygienic than untreated wood.

WHAT EMITS RADIATION IN A HOME?

This is not about the sun's radiation, it is about comparing all types of radiation which people are exposed to in daily living situations as a consequence to the building materials which have been used.

We conducted a research on average exposures to radioactive radiation through naturally occurring sources vs. man-made/artificial sources.

The average radiation exposure in Germany is 150 millirem (mr). Just by living in homes with a variety of individual building materials, the following has been recorded:

Granite/Slag: +150mr = 300mr
Plaster: +65mr = total 215 mr
Brick and Concrete: +20mr = total 170mr
Natural Wood: -10mr = total 140mr
The only building material which can actually lower radiation is natural wood.

Who isn't familiar with a hoarse throat in winter, when the central heating is running on full steam? The dry air and stirred dust strain our breathing and it can be as unpleasant as high humidity levels. A superior building material buffers and balances moisture independent of whether it is extremely humid or dry. Untreated wood has a large inner surface area where the countless pores, capillaries and micro-tubules react to changes in the moisture levels of its surroundings.

While the humidity rises, wood absorbs moisture and dries up the air. When humidity levels drop and the air dries up, wood releases some of the retained moisture back into the atmosphere and maintains balance. Timber is the ideal moisture buffer for any building. The more natural wood there is in a house, the better the buffering effect.


"Whoever still has concerns about untreated wood being suitable for bathrooms will be surprised by the following story. It is true, bathrooms have the most extreme climatic changes in any home and in the early years of manufacturing, I too declined to build bathroom floors. I was afraid about the spaces and movement between the floorboards.

However, the following experience led me to a vital realization:

One day a carpenter, also a colleague, ordered cherry tree floors for one of his clients and didn't tell me who or what it was exactly for. As promised, we delivered his cherry tree floorboards and a little while later, he rang to let me know that the floor turned out very nicely. I asked him if his clients were happy with it and he said: "very much so!"

A few months later, I went to visit him and was greatly surprised to find out that he was the client himself. He led me into his bathroom and showed me his cherry tree floor which was very neat and tightly installed, with no signs of gaps and movement between the boards. The carpenter told me with a grin on his face that he knew about my cautiousness and he wanted to spare me sleepless nights. But he always knew that untreated wood could be used even in bathrooms, as long as it has been harvested at the right time.

From the result of the bathroom floor inspections resulted in three happy faces: his wife's, looking proudly at her beautiful & natural cherry floor, the joyful carpenter's and my own face which must have looked rather surprised, judging by his chuckling. Since this event, we have delivered and installed many natural wooden floors for bathrooms and found that natural and untreated wood balances the air humidity in all cases.

For example, if the humidity in a room rises from 35% to 65%, 1M² of spruce cladding absorbs up to 10 grams of moisture in 12 hours and dries up the air. This works the opposite way too. If the air in a room is suddenly very dry, wood slowly releases moisture back into the air.

We found that after installing natural wood ceilings, wall claddings and/or floors in the bathroom, the mirror rarely fogs over and hardly any condensation water appears when you have a shower. You can try this experiment too!

You need to be aware though, that plywood, chipboard, and wood component panels that are sealed and laminated completely negate this buffering effect of wood. These advantages only take effect when you use solid, untreated, adhesive-free wood like Holz100 which is able to breathe freely on its own."

- Dr. Erwin Thoma, Founder & Inventer of Thoma Holz100

​Wood breathes in all components - this is a great natural advantage when creating living spaces. Holz100 has a low diffusion resistance and a high level of airtightness which allows us to provide a 50-year guarantee against condensation and mold.

The high degree of breathability combined with the airtightness of Holz100 results in a multifunctional solution – a building material that doesn’t require elaborate layer arrangements in walls to achieve the ideal indoor environment.

As the Holz100 building component consists only of wood, it has no boundaries in permeability between its layers. On the other hand, common building systems consist of layers of different materials which easily cause varied vapour permeability and condensed air humidity. However, for Holz100 homes, there is no necessity for vapour barriers as the wood breathes by itself and naturally controls the indoor climate.

Holz100 has a diffusion resistance of u=37.2m. This means that for a 17cm thick Holz100 panel, the diffusion equivalent in air layer thickness is 6.3m (according to EN ISO 10456, vapour diffusion resistance of solid wood is u=50).

The airtightness of Holz100 ensures no unnecessary heat loss. Holz100 residents have the advantage of a healthy, ideal indoor climate with high energy efficiency. Holz100 walls are airtight on their surface due to multiple layers of cross laminated solid wood and can reach 0.6 if put through the Blow-Door Test.

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Permeability and Airtightness

Holz100 is a cross-layered thick wall which consists of only one material - wood. Therefore, there is no fluctuation in vapor permeability within the wall and it does not condense any air humidity, unlike vapour-blocking films or impermeable insulation materials which are frequently used in conventional methods of construction.

Since structural engineers and technical institutions have been able to prove the airtightness of buildings through thermographic recordings and/or appropriate tests such as the "blower door test", a lot has changed. The world of wooden houses became divided into the good (leakage resistant) and the bad (high air leakage) in terms of energy efficiency. Wooden houses, whistling from all holes, are unfortunately not a rarity, and are quite wrong in referring to the building material as "wind barracks".

Leaking grommets, balconies, sockets and walls are the main causes of air leakage in wooden homes, but they have nothing at all to do with the material itself. The fault lies with its inadequate engineering & processing of structural components.

A careless plumber or electrician who bores a hole through the wall after the carpenter's work suffices to destroy everything again. The borehole acts like a needle puncture of an inflated plastic bag - there goes the building's energy efficiency. From the source of cold air enters condensation, moisture, mold and odor from behind the framework, plaster or plasterboard in the winter.

The best way to avoid this is to build with our solid wood construction - Holz100. In our case of homogeneous walls, the vapor pressure is not abruptly trapped in a film layer, but is "gently" degraded throughout the entire mass. Holz100 walls are tight even at the highest wind pressure thanks to its high precision and quality of prefabrication. The connections of the wall elements are produced in a manner of utilizing a tongue-and-groove system which makes our system secure and airtight. The surfaces can then remain natural or be painted, plastered, clipped, etc. depending on the homeowner's tastes of interior design.

"Forests are the lungs of our land, purifying the air and giving fresh strength to our people." -Franklin D. Roosevelt

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Wood as a natural air conditioning system

Temperature fluctuations, uncomfortably hot/cold wall surfaces and fluctuating humidity values are alien to residents of Holz100 homes. You can now experience well-being indoors in an ideal climate.

The time it takes for a house to heat up in summer and cool down in winter depends on the insulation materials that are being used. However, the bigger influence comes from the building material itself. At the University of Graz, we tested the three most commonly used building systems.

The experiment was simple:

A wood frame wall, a brick wall and a Holz100 wall were prepared with insulation materials to achieve the same thermal insulation rating. Each wall was exposed to a constant temperature of 21 degrees Celsius.

To simulate winter in the laboratory, the outside temperature was then lowered to minus 10 degrees Celsius and the inside heating turned off, as if the tenants had turned off the heating and left. We applied the same conditions to all three walls and measured the time it took for the cold to penetrate through the wall and reach zero degrees on the internal wall surface.

Here are the results:

Standard stick-frame wall home: 41 hours
Brick wall home with insulation: 259 hours
Thoma Holz100 home: 777 hours

Compared to other building materials, wood has an excellent heat storage capacity and therefore only cools very slowly. The wooden house not only warms in winter, but stays cool in summer. Summer heat also penetrates slowly from outside to inside, as does heat from the inside to the outside.

The Thoma Holz100 wall does not only offer fantastic U-values, but it also dominates much more. For example - as a solid, monolythic, but above all organic building material, it has superior heat storage capacities which are twice as high as those of conventional mineral wall building materials. This results in particularly high cooling times, since the U-values of Holz100 walls and excellent thermal storage capacities are unified in a unique way.