Timber frame technology leads the way in meeting & beating future CO2 emission targets

BY MIKE CRUICKSHANK OF SCOTFRAME TIMBER ENGINEERING
In a year that witnessed the death of Sir Winston Churchill, the arrival of US troops in South Vietnam and the abolition of the death penalty in Britain, it is not surprising that the introduction of new environmental building regulations were not headline news in 1965.

However, as the environment has become one of society’s keenest priorities, the thread of green legislation that began in the Sixties has fast developed into a thick rope of regulatory standards and requirements.

This is clearly something the construction industry has been following closely and with forthcoming deadlines looming large on the horizon, there will be no let up in the pressure to improve the thermal performance of new buildings.

Come October 2010, the Government will slash the level of permissible CO2 emissions generated by new builds by 30 per cent. There is a further reduction of 30 per cent planned for 2013 and yet another of the same amount due to come in to force in 2016.

The vast bulk of emissions generated by a property come from its central heating and having to provide hot water. There have been advancements in boiler technology and there is no doubt that modern systems work more effectively and efficiently than their predecessors.

However despite the gains that can be made in this area, the major improvements come from improving the thermal performance of a property and so reducing its reliance on central heating.

Indeed we are getting to a stage where some properties are so thermally sophisticated that traditional central heating systems are not required and heat can be generated and maintained in much more minimalist ways.

Thermal efficiency relies on the ability of the walls, floors, roofs and external joinery to create an effective thermal envelope. By eradicating drafts and utilising materials that retain heat, it is possible to create a controlled environment and keep a steady ambient temperature with very little energy expenditure.

In the most thermally sophisticated buildings, the heat produced by electrical equipment and even the body heat from its occupants have to be taken into account when designing the heating system as so very little of the heat generated is lost through the buildings fabric, indeed there may be no need for a heating system at all.

Between 1970 and 2003, the percentage of UK homes with central heating rose from 31 per cent to 92 per cent. While it is unlikely we will ever see things drop back to how they were in the Seventies, it is likely that an increasing number of new homes will not install central heating, but instead rely on wood burning stoves, range cookers or individual electrical heaters, as the building envelope itself is so thermally efficient, it is able to retain the heat generated by such appliances so effectively.

One particular leap forward in this area has been the introduction of the Supawall system in timber frame construction. In recent years, standard practice has been to erect an open panel timber frame and then insulate and seal the panels with plasterboard.

Now, however, closed panel timber frames are leading the way into the next generation. These frames have been insulated and sealed at the factory and operate to the highest possible standards.

To measure the thermal efficiency of walls, a ‘U’ value was introduced with the 1965 legislation. In technical terms it measures the amount of heat lost per square metre, for each degree Celsius of temperature difference between inside and outside. In laymen’s terms, the lower the number the better.

In 1965, the ‘U’value limit introduced for walls was 1.7 and has since dropped to 0.3. The Supawall system has a u-value of 0.11, 2.7 times better than today’s required standard and 15.5 times better than that of 1965.

While renewable energy sources, efficient boilers and improved heating systems all have their part to play, investing in the actual fabric of a building is the fastest and most effective way to reduce the amount of energy it uses and in turn the CO2 emissions produced.

There may be a slightly higher cost for such excellent standards of insulation, but there is no ongoing maintenance to think about with Supawall and the savings involved are immediate, significant and last for the lifetime of the building.

As more pressure is put on the construction industry to deliver excellent environmental performance, there is likely to be a greater reliance put on solutions that deliver effective, reliable and substantial results.

In practice this seems set to see more architects, builders, developers and housing associations turn towards the benefits of the Supawall system and turn it into the industry standard of the future.