Most of the materials, techniques and crafts used to build single or small groups of houses in the UK have remained essentially the same for centuries. Masonry construction, the tried and tested method of creating a good, solid wall has been around since the Romans. Even cavity wall construction, still considered a relatively recent innovation by some, has been around since the early 19th century.

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In October 2010 the building regulations covering heat loss, energy use and insulation requirements were tightened up, as were the rules controlling the air tightness of new homes. The impact of these changes has been muted, because all that is needed to comply is extra insulation, slightly better quality control on site and maybe a little less glazing. However these rules are going to be ratcheted up in 2013 and again in 2016. The demands that will be placed on the fabric of all new houses will be such that it will be difficult and certainly much more expensive to build using traditional methods.The regulations now require the energy use of the building to be looked at in its entirety. This means that it is possible to trade-off the use of lots of glass by increasing the thickness of the insulation, or installing renewable energy sources such as solar panels. However, to comply with the future regulations, it is likely that insulation in the walls will have to be 150mm thick or more. Although it is possible to build a cavity wall with that level of insulation, the overall wall thickness that results is at least 350mm. This requires more expensive lintels and reduces the width of the rooms to noticeable effect in smaller houses.The regulations will also require that the standard of construction is very high, because gaps left between insulation, blobs of mortar or steel lintels bridging the cavity start to have a bigger effect on heat loss. Quality control during construction of a cavity wall is difficult because as it is built the insulation is concealed between the two masonry leaves. The only way a building control officer could be sure that insulation is being fitted absolutely correctly is to be on site continuously, which is obviously impractical.

All this means that once the new regulations begin to bite, building a cavity wall will be significantly more expensive and harder to justify than at present. This does not mean that masonry construction will disappear. The extensive range of skills available in the UK workforce will probably make an alternative to cavity walls, such as solid wall construction with insulation fixed to the outside, affordable. But it is likely that that the image of the traditional English brick house will have to be rethought because render or timber cladding will be more logical choices.

Aside from prompting a move away from cavity wall construction there are some other influences that the regulations will have on the design and construction of homes. Buildings can be orientated to gain heat from the sun in winter, with large overhangs above windows to prevent overheating in the summer. Turf roofs help insulate a building, provide greenery in urban areas and also help to reduce the surface water load on the drains. These features make a house look quite different to the traditional ‘dream home’ of a cottage in the countryside.

It is likely that in the next few years there will be an explosion of different construction methods as we experiment to see which works the best. Eventually there will be winners and losers and the few that are most popular will dominate. Builders will have to adapt to the new requirements at lightning speed by comparison with rate of change they have been used to in the past. Although this presents some problems, it will be an exciting time for anyone involved in the designing and construction of houses.

The Building Regulations:

•2010: 25% reduction required in carbon emissions when compared to the 2006 regulations. This is same level required by Code for Sustainable Homes Level 3.

•2013: 44% reduction on 2006 level, which is equivalent to CSH Level 4.

•2016: Zero carbon homes required – but what this means in reality is under review. It is equivalent to CSH Level 6.

Changes to the Building Regulations

Energy efficiency is covered by Document L of the Building Regulations. The Code for Sustainable Homes is not part of the regulations, but give targets for the energy efficiency and other sustainability issues of new homes. It rates houses from Level 1 to Level 6.

Written by Julian Owen © Future Buildings

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www.julianowen.co.uk

Julian Owen is a chartered architect, running his own practice in the East Midlands. He is chairman of ASBA architect, has wrote many articles for a number of highly regarded magazines and an author of several books on topics such as self build and house alterations.


Any questions about this article? Simply leave a comment below and Julian will be in touch.