Park End Street Developments, Oxford

According to the Building Regulations, homes heated entirely by electric systems are permitted to create more carbon emissions than homes heated by other methods, and in particular by mains gas.

This has been incorporated into the mandatory energy/carbon section of the Code for Sustainable Homes which requires homes to make further percentage carbon savings on Building Regulations to meet the different code levels (for example level 3 requiring a 25% reduction and level 4 requiring 44%).

This is particularly a problem at Code levels 3 and 4. It means that an electrically heated home can be classified as level three, despite its carbon emissions being greater than the same building heated with gas to basic Building Regulations level (i.e. Code 0). This problem is compounded by the fact that electric heating is cheaper to install and easier to make percentage carbon emissions improvements than through adequate insulation. This is driving some people to use electric heating as an easy option to meet current Code requirements. This could lead to thousands of homes emitting more carbon than under the present Building Regulations and not addressing the real issues of carbon reduction, sustainability and climate change.

Preventing Sick Building Syndrome Another potential problem which needs to be addressed when considering the Code is that by increasing levels of airtightness to reach the higher level requirements, there is a significant risk of increasing trapped moisture. This can impact both on the building’s fabric and also its inhabitants.

Moisture in buildings is mainly dealt with through ventilation systems.

However ventilation systems are not fool proof. They need to be designed, installed and maintained properly. They also need to be carefully adapted when the building form is changed. Until now if ventilation systems failed there was always the unsatisfactory default mechanism of the leaky building shell, which acted to disperse moisture in some way, although often very badly and with other negative effects. However with new standards of airtightness being essential for higher code levels, this default mechanism no longer exists meaning that the risks to human and fabric health of badly ventilated houses at high code levels have increased considerably.

This situation can be eased by the use of natural, vapour open building products, which provide exceptional levels of breathability for the building fabric.

Allowing the building envelope to breathe, or expel moisture to the outside, not only protects the integrity of the building fabric, but can help to create a healthier environment inside.

Using conventional building methods (and particularly vapour closed insulations, vapour barriers, and other impermeable materials) moisture can often get trapped within a wall. This is either through the inability of the wall to dry out properly from rain penetration of the outer skin (especially during construction) or because of interstitial condensation, which is increased where cold bridges occur. This can lead to longterm problems for both building fabric and occupants.

Both the Government and the construction industry have begun to recognise the importance of using building products that improve the environmental credentials and health of buildings, as well as their building performance. This is where ecological building solutions can help.

One key benefit is that they significantly improve the health of buildings and their inhabitants to such an extent that they can be used as solutions to sick building syndrome. For example, the dramatic rise in cases of asthma and bronchial illnesses in the UK, along with other damp and mould related illnesses, is thought to be largely as a result of trapped moisture in buildings.

Together with good ventilation systems, building systems consisting of natural, ecologically sound products can uniquely help to reduce moisture in buildings through their breathable hygroscopic qualities and fully vapour open designs.

The Solution NBT’s ecologically sound, high performance Thermoplan, Pavatherm, Pavatherm Plus and Diffutherm insulation systems create a wellinsulated, healthy interior environment by allowing the building fabric to breathe.

NBT also offers a whole range of additional ecologically sound products, which are designed to construct the entire building envelope, complete with internal and external finishes.

These high performance building solutions consist of proven and tested ecological materials and incorporate products such as plasters, renders, boards and mortars, as well as blocks for solid wall construction, insulation products and paints.

Maximising the Code The Code for Sustainable Homes has the potential to drive forward a real step change in the way buildings and communities are constructed in the future. However, for this to happen, the loopholes need to be closed and genuinely sustainable methods of construction and products need to be incorporated to achieve the full environmental benefits.

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