What to look for when insulating your new build
Matt Rhodes, the national specification manager at one of the leading insulation manufacturers, Actis, talks through the key features to look out for when building an energy efficient home
because building regulations demand it (and rightly so) and because without it your fuel bills are only going to get higher. There are two main ways to reduce fuel bills
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– one is to generate your own energy through technology such as solar and solar PV panels, air and ground source heat pumps and the like. The other – which can be done in combination with this – is to stop the heat escaping from the building in the first place. In fact, there’s no point in making the upfront investment in renewable energy if that is then going to leach out of poorly insulated walls and roofs. Nowadays, with the tightening of Part L building regulations (which govern the thermal efficiency of a building) fab- ric energy efficiency or building a well insulated home is essential. While builders are given an element of
flexibility on how to balance the efficiency of the building fabric itself and its services to reach the required carbon emissions level, this FEE is designed to ensure that developers can't build homes whose envelopes are inefficiently
reviously the preserve of particularly green leaning people, energy efficiency is now a vital component of a new build – both
constructed and make up the deficiency with excessive use of renewable technologies. One of the key elements of the Part L regulations states that insulation should be reasonably continuous over the whole building envelope. The building fabric should be constructed so that there are no reasonably avoidable thermal bridges in the insulation layers caused by gaps within the various elements, at the joints between elements such as those around the window and door openings. Reduction in thermal performance can occur where the air barrier and the insulation layer are not contiguous and the cavity between them is subject to air movement. This means that it’s worth looking at an insulation which is flexible and can squash into gaps and bend round corners easily – areas which are notoriously difficult to insulate because of odd angles – thus creating a draught or thermal bridge. Added benefits of these types of insulation are that they’re quick, clean and easy to install, don’t create dust or fibres and are light and easy to transport. If you’re paying someone else to install the insulation then the labour fees should be lower.
Make sure of course that the products are CE marked, and are approved by the NHBC and have what’s called LABC registered details. This means that building control officers can just wave it through as it can be accepted by build- ing control surveyors in local authorities across England and Wales when used according to the certification. It’s also worth using both a vapour control
layer and a breather membrane. While there is no legislation stating that a vapour control layer must be used, they are recommended because they massively reduce the risk of con- densation. Some vapour control layers are dual purpose and also act as an insulation, which means the thickness of the main insulation can be reduced to achieve the same required U- value. It is used on the warm side of any insula- tion material, behind the internal finish in roofs, walls and ceilings. A breather membrane is ideal for moisture
control. Again, like the vapour control layer, some are dual purpose, and also act as insulation. Reflective and watertight, yet vapour permeable it’s used on the cold side of roofs and walls. Because water vapour molecules are
selfbuilder & homemaker
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