SAP Calculations show compliance with Part L* of the Building Regulations. “SAP Calcs” are required by Building Control at the design stage of a new dwelling to show how the building will comply with Part L. Once built, the dwelling requires a new set of SAP calcs to show that what is built complies with Part L. At this stage we produce the as-built SAP calculations & provide the EPC (Energy Performance Certificate) based on the as-built spec.
SAP calculations are produced by interpreting & inputting dwelling data (areas, volumes, u-values, heating/cooling systems, renewables, etc) into software to show how the dwelling compares to a ‘notional’ building. The dwelling ‘passes’ when the CO₂ emissions (DER) and building fabric (DFEE) are better than the notional building.
Building Control will ask for SAP calculations if your extension or conservatory has glazing that is greater in area than 25% of the extension floor area (glazing includes rooflights and glazed roofs). We show compliance by producing 2 sets of SAP calculations, one showing a ‘notional’ extension, and one showing the ‘proposed’ extension. The CO₂ emissions of the ‘proposed’ extension must be no worse than the ‘notional’ extension in order to comply with Part L1B.
* Building Regulations Part L is concerned with Conservation of Fuel & Power. (or Standard 6.1 of Scottish Building Standards in Scotland).
We provide Part G Water Calculations to show that the water usage of a new dwelling meets the requirements of Part G. Currently the Building Regulations require a maximum water consumption of 125 litres/person/day (125 litres per per person per day) in order to comply.
125 l/p/d is fairly easy to achieve with modern sanitaryware but can become tricky where large baths or powerful showers are being used – In these cases it is necessary to offset high usage in one area with low usage in another, or use alternative water sources to offset high usage (e.g. rainwater or greywater harvesting).
An increasing number of LPA’s (Local Planning Authorities) require new dwellings to provide a percentage of energy demand, or CO₂ emissions reductions, from using on-site renewable energy sources.
Whether the requirement be for a 10% CO₂ emissions reduction, 20% energy demand reduction or CSH4/CSH5 Energy, we have experience of providing reports to satisfy Planning Authorities across the whole of the UK.
Compliance can be as simple as installing a small PV (photovoltaic solar) array or installing a heat pump, depending on the requirement. For multiple dwellings it may be possible to achieve compliance by installing renewables on just a small number of dwellings in a development, depending on the wording of the planning condition.
Contact us to discuss how we can help you comply.
Air Testing shows how airtight a building is. The more airtight a building is the less heat energy can escape. A building’s SAP calculations will normally assume a certain level of air tightness in order to achieve a ‘pass’.
An air test is conducted by temporarily installing a fan into an external doorway of a dwelling and either blowing air into, or sucking air out of the building. The fan is set to a series of different fan speeds to show how much air can enter or escape the building, thus showing how airtight the building is. The result (q50) is measured in m3/hour/m2 surface area, (or n50 for Passivhaus, ACH – Air Changes per Hour).
The maximum q50 allowed in a SAP calculation is 10.0, although a result of 5.0 or less is typically achieved.
New dwellings that are attached to each other (flats, semi-detached, terraces) will require sound testing to show compliance with Part E.
Sound testing through party walls and party floors is conducted using sound meters to show compliance.
Code for Sustainable Homes was abolished in 2016 but aspects of it still exist, as well as legacy cases and planning approvals.
Some LPA’s require a certain “Code level” to comply with a renewables or energy related planning requirement, e.g. some London boroughs require “CSH level 5 Energy”, meaning that only the ENE1 energy section is required, rather than the whole CSH – this isn’t easy to achieve however, as CSH5 energy is essentially zero carbon in SAP.