Solid wood wall building

“Climate change cannot be won without the world’s forests. ”

Ban Ki-moon, UN Secretary-General, September 2008


Trees remove carbon dioxide from the atmosphere as they grow and are widely recognized as a cost effective way to tackle climate change. A recent UN FAO report shows that deforestation accounts for 17.4% of the world’s CO2 emissions. This is greater than the emissions from all forms of transport. 13 million hectares are being deforested each year but 6 million hectares of new forest is being planted.


The Kyoto protocol, with emissions trading, encourages more new forest planting and less deforestation. Some see this as a short term solution because much of the carbon can be returned to the atmosphere when trees are harvested, or if they are left to eventually die and rot in the forest.


There must be another way. The best technology from New Zealand and Europe shows that harvested wood products can be several times more effective than just growing trees at tackling climate change. This happens when wood is used in 4 energy saving ways.


1/ Use wood for long term purposes such as building and furniture so that the carbon is stored for a long time. The more wood that is used the better.

2/ Use wood instead of other more energy intensive materials such as steel, concrete, plastics and aluminium.

3/ Make use of the insulation and thermal mass qualities of wood to create very energy efficient buildings which are very easy to heat and cool.

4/ Use wood waste as a carbon neutral fuel in efficient heaters and boilers.


Solid wood buildings use more wood and less other materials than timber framed buildings. New Zealand has a great solid wood building tradition. The following press release tells the story.

Press Release

40,000 NZ home owners were right all along


Many people who have lived in solid wood houses comment on how warm and comfortable they are. This is in spite of these houses having walls with a low R value. A group of companies wanting to promote solid wood buildings asked Dr Larry Bellamy of University of Canterbury and Don Mackenzie from Lincoln University to research why these houses performed better than their R values indicated. The results of this work was quite a surprise to the researchers , but probably no surprise to the 40,000 families living in solid wood houses in New Zealand.


The first thing they found was that solid wood has significant thermal mass giving it the ability to store the sun’s heat during the day and releasing it at night. Brick and concrete are often used because they provide useful thermal mass but wood has up to 2.5 times as much thermal mass as concrete per kilo. Dr Bellamy was able to use a building simulation model from Denmark to show that when this thermal mass effect was added to the relatively low R value of the external walls, a solid wood house compares very well to a light timber frame house built to the NZ building code. The solid wood house performed even better when solid wood internal walls and ceilings were used.

The merino effect


Probably an even more important discovery was the effect solid wood walls have on the health of people living or working in such a building. It has become well known among researchers that relative humidity in buildings needs to be kept between 30% and 55% to avoid the build up of bacteria, viruses, fungi and mites, and to minimize respiratory infections and asthma. Dr. Bellamy found some research from the Fraunhofer Institute, near Munich in Germany, which compared 2 identical rooms. One had walls lined with solid wood and the other with painted plaster board. Water vapour was added at different times of the day to simulate people living in the rooms.


The solid wood lined room was found to have a remarkable ability to moderate over 50% of the moisture variations so that the room was only outside the safe humidity zone for 3% of the time compared to 27% of the time for the room with the painted plaster linings. This research from Germany indicated that the health benefits of living in a solid wood house are likely to be even greater than just the thermal comfort.


Many of us have become aware of the benefits of wearing merino, especially for strenuous outdoor activities. The merino is able to work naturally with the body to store and release moisture and stabilize body temperature. Merino also has the ability to reduce the build up of unpleasant odour. Wearing merino and living in solid wood houses both help keep the body healthy and active.


Can you destroy a solid wood building?


Solid wood buildings have withstood severe storms and earthquakes when nearby buildings have suffered catastrophic failure.  Notable examples are Cyclone Tracy in Darwin Australia and the Edgecombe earthquake in New Zealand.


Solid wood walls can take the hard knocks when used in kindergartens or motels and can have minimal maintenance costs compared to painted plaster walls. Solid wood even performs well in a fire and can be restored after a minor fire.


Solid wood’s ability to moderate humidity and to breathe means that it can survive, in a wide range of climates, probably for hundreds of years. If it needs to be moved, it can be moved as a whole house, or dismantled and rebuilt on a new site.

Tackling Climate Change with Solid Wood Building


While there is still uncertainty about the best way for New Zealand to tackle climate change and meet Kyoto commitments, growing trees to store carbon is likely to be the most cost effective way. A farmer can plant a low value steep piece of land and store over 20 tonnes of CO2 per hectare per year for the next 30 to 50 years. When the trees are ready to harvest, if the wood is used for a solid wood building, it can keep that carbon stored for maybe hundreds of years. It also saves the use of energy intensive materials such as concrete, steel and brick. And because solid wood buildings are easy to keep warm, more energy can be saved. Solid wood building saves considerable amounts of precious fossil fuel energy compared to other building systems, as well as storing significant amounts of carbon over the life of the building.

Exciting Future for Solid Wood Building


A revolutionary new solid wood building system using cross laminated timber panels has been developed in Europe because of concern for healthy living spaces and the need to tackle climate change. One of these systems from Austria can be seen at  Panels up to 16.5 metres by 3 metres are precisely cut in the factory so that a building can be erected very quickly on site.


An example is a 9 storey apartment block at Murray Grove near the centre of London. This 29 apartment building took just 9 weeks to erect and all units were sold before project started – a property developer’s dream. It has a wood composite exterior and the whole building, even the lift shafts were made of wood. This means that it will be 21 years before the operational emissions equal the CO2 stored in the building structure. See picture of this building.


Another example highlighting the strength of solid wood is an amazing café projecting out 12 metres over a river. This can be seen at


Another example highlighting the versatility of solid wood building was a whole Olympic village built for the winter Olympics in Italy. Each unit was assembled and fitted out in a factory and then dropped into place by a crane. After the Olympics, each unit was then picked and moved elsewhere.

Who benefits from Solid Wood Building?


Those living in Solid Wood houses – They are fortunate enough to have a warm, healthy home.  Living in a healthy house means less doctors visits and less sick days. Solid wood houses are virtually indestructible and if rising sea levels caused by climate change threatens their home in 100 years it can be picked up and moved to higher ground.


The NZ Government and taxpayer – Each house built with solid wood rather than steel, concrete or brick saves many tonnes of CO2 emissions. This reduces the Govt’s and taxpayers’ Kyoto liability. Reduced health costs will be an even greater saving when solid wood is used instead of painted plaster.


Farmers, foresters, sawmillers and manufacturers – Solid wood buildings use several times as much wood as a timber frame building, as well as much less other building materials. This leads to more demand for more forests, processing and manufacturing.


Everyone Benefits – Everyone benefits when sustainably grown materials, which need little processing energy, are used instead of materials which make heavy use of the earth’s limited resources. Wood is the world’s only renewable building material so using more wood and less other materials will help save the planet.


The NZ SolidWood Group – Leading edge science around the development and performance of solid wood building has been driven in New Zealand by the SolidWood Group, a group of visionary companies seeking to bring to the users of buildings and homes the healthiest living environment possible. For more information on these companies go to