How will it impact anyone planning on building a new house?
Part L, Code for Sustainable Home, BREEAM
You may have heard of the Code for Sustainable Homes, BREEAM and other sustainability schemes. It was often required for developers or homeowners to achieve certain levels on these schemes in order to obtain permission for their projects.
In the governments’ latest Housing Standard Review, the requirement to meet these standards has been removed from the planning process. Instead there will be a requirement to prove sustainability of the house at building regulation stage (after planning has been granted) under Part L of the Approved Document of the building regulations. Behind this approach is the governments’ apparent intention to simplify the planning process and unify the sustainability requirements across the country, increasing certainty amongst developers and self-builders.
Part L deals with energy efficiency of houses (and other buildings) and outlines how much energy your house should use and how much CO2 will be produced in the subsequent running of the house. It’s a complex piece of legislation and in practice if you are deciding to build your own house this will mean commissioning a special report. It is called an SAP report and it models energy consumption of the house. In reality it will dictate how much insulation should be used in your walls, floors and roofs and whether you need a ventilation system or renewable energies provided as part of the build.
‘U’ values show how well insulated your walls, floor and roofs are (lower figures are better). The following chart displays the U-Values for new build properties, showing the difference between the previous regulations from 2013 and those anticipated in 2016 when the government is aiming for ‘zero carbon’ housing.
|Glazing (windows)||1.4||1.2-1.4 W/m2K*|
|Thermal Bridging||0.15 max||0.04-0.07 W/mK*|
|Air Permeability||5||c. 2-5 m3/hr/m2 @ 50Pa|
|Ventilation||Natural (local extractor fans)||Probably MVHR|
* figures from www.zerocarbonhub.org
As you can see there are very little expected differences between the 2013 and 2016 regulations in terms of how well insulated walls, floors and roofs are. The real differences are likely to come from improvements in thermal bridging values, air permeability, ventilation and renewables, each explained below.
- Thermal bridging: this is where elements of the building meet, such as where a floor meets a wall. Traditionally, this is where a building loses a lot of its heat. The new guidelines will require these junctions to be designed and built to a higher standard.
- Air permeability: the technical name for when a house is “leaky” and has draughts around old sash windows. The new regulations will require buildings to be designed and built to a better level of ‘airtightness’ and will include air tightness membranes and the use of higher specification doors and windows.
- Ventilation: previously this had often been through ‘trickle vents’ in the tops of windows or simple extractor vents in bathrooms. The new regulations are likely to require a whole house ventilation system, which recovers heat from the old air, or ‘MVHR’.
- Renewables: on site generation of power or heat, such as solar panels, heat pumps, wind or other micro-generation.
The new Part L allows more flexibility, so an improvement in one area can allow a lower level of performance in another as long as the overall performance of the house meets a predefined value. It is likely to be announced that developers can offset this carbon to reach the proposed zero carbon level for homes, a cost which will need to be considered during planning.
Useful tricks for achieving high thermal performance without increasing wall, roof or floor thickness:
- To keep a 100mm cavity and achieve requirement
- To keep roof build ups thin, an innovative, but expensive, very highly performing insulation system, allowing for thin insulation layers
- ‘Heat mirror film’ as an alternative to triple glazing
Part M and Lifetime Homes
The Lifetime Home Standard was implemented in 2010 and is required by most councils in the UK for any newly built home to comply with the principles of;
- Inclusivity – must assist everyone regardless of disability, age or gender
- Accessibility – must be useable by the largest possible group of people
- Adaptability – must be able to develop as the needs of those living there do (see inclusive design)
- Sustainability – must contribute to the community and individuals long-term
- Good Value – must not be overly complicated or expensive for builders or those living there
This standard will now be dropped from the planning process and instead will be picked up later in the project as part of the building control application. The current part of the building regulations which deal with accessibility will be beefed up to provide three tiers of compliance. The council may still place requirements on a new house to reach a certain standard in Part M, but this will be dealt with and approved as part of the building regs application.
The three tiers proposed for the new Part M will be:
- Houses visited by disabled people
- Houses adaptable for disabled people
- Houses designed for disabled/wheelchair using people
This regulation will now be entirely dealt with by building control rather than planners by 2016, though planners are able to place requirements for one of these levels through a planning condition.
Part Q and Secured by Design
Secured by Design (SBD) is the current UK Police flagship initiative which supports the notion of designing out the risk of crime to homes and commercial property, ‘leading to a reduction of 75% of crime risk’. As with Lifetime Homes, this SBD will become largely redundant and be replaced by a ‘beefed’ up new section of the building regulations, Part Q.
Part Q will specify the security of the internal living areas of a new property, including window and door specifications. However SBD will remain in force for communal areas, including shared entrances, communal halls and external areas. This largely includes regulation on the materials, workmanship and notifications involved in the building process, resulting in a more prescriptive approach to security in homes.
Part G and Water
Part G, involving sanitation, hot water safety and water efficiency are largely unchanged from 2013; apart from a new cap on usage of 125 litres per person per house per day, added temperature resistance and a measure to prevent water from heating to temperatures greater than 100ºC.
In Conclusion, what can you expect from Part L?
If you have an existing home there are unlikely to be any significant changes, as is true for listed properties which are being redeveloped (on a case-by-case basis). However, for new builds regulations will require your new house to meet carbon zero standards when they come in, likely during the Spring of 2016. Overall this leads to a reduction in the effect that planners have on requirements as this regulation dictates that Part L, M and G2 largely become the domain of building control officers.