Guidance for changes to Part L and Part F
The long-awaited update to Building Regulations was announced in December 2021 - a significant update that focuses on the existing energy efficiency standards for homes and marks a steppingstone towards the introduction of the Future Homes Standard in 2025.
The new Building Regulations comprise five new documents, with the ones that mainly affect our industry being Part L (heating and energy) and Part F (ventilation). This will come into effect from 15 June 2022, and will have a marked impact, particularly on new, but also on existing homes.
Each country has their own guidance and, for now, we will concentrate on the regulations for England.
Part L
Presently U-Values are 1.4W/(m2K) for windows going into new homes, and 1.0-1.4 W/(m2K) for doors depending on glazing. Under the Part L 2022 changes, these will be 1.2 W/(m2K) for windows and 1.0 W/(m2K) * for doors. For refurbishments in existing buildings, there are higher figures of 1.4 W/(m2K) for windows and doors.
*1.0 Opaque doors (less than 30% glazed area, 1.2 for Glazed doors (more than 60% glazed area)
It’s worth noting that these figures are based on desirable values to be inputted into SAP when Building Regulations calculate the ‘notional building.’ They aren’t used in isolation, and they’re also not absolute, to allow for flexibility in building design.
To put it simply, the notional building is a digital shadow of the exact building and uses fabric values issued by the government through Building Regulations. Several exact values are entered into SAP for things such as thermal properties, space heating and air tightness. These are then compared with the notional building. If a window doesn’t meet a value of 1.2, (if it is a Vertical Slider for example), a limiting value can be applied and other areas of the dwelling can be improved to offset this, such as better insulation. The limiting value is the worst value a product can perform at.
That said, it will be more difficult for specifiers to achieve the desired Energy Efficiency Ratings, as the calculation has also changed, allowing for less ‘wiggle room’.
In summary, it will be more difficult to meet the new U-Values, BUT calculations are NOT based on individual products.
Consideration must also be given in Part L to the fitting of frames to ensure they maintain an air barrier using air sealing tape. Compressible seals or gun sealant may be used to supplement the taping.
It is the responsibility of the installer for compliance to the building regulations.
We are working with our suppliers to confirm what changes need to be made to our product range and will keep you updated.
Part F
Approved Document F has caused a lot of controversy in the industry since being published. For new build, the requirements are: