Our services for Residential buildings

SAP Calculations - for new dwellings (Part L1A) & converted dwellings (Part L1B)

SAP Calculations show compliance with Part L* of the Building Regulations. A SAP Assessment is 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 further set of SAP calcs to confirm that what is built still 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 energy efficiency (DFEE) are better than the notional building.

More Info

SAP Calculations - for over-glazed extensions & conservatories (Part L1B)

Building Control will ask for 'Notional vs Proposed SAP calculations' if your extension or conservatory has glazing that is greater in area than 25% of the extension floor area (glazing includes rooflights, glazed roofs and roof lanterns). 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).

More Info

Introducing our new Fast-Track SAP service, ASAP:

Our New priority SAP calculation service

For a small fee you get your SAP calcs quicker than our standard turnaround - perfect for rush jobs to fit in with your timeframe.

Part O Overheating Calculations & Reports

We provide Part O Overheating Reports to show that a dwelling complies with Building Regulations Approved Document O (Overheating).

We supply reports based on the Simplified Method as well as Dynamic Thermal Modelling for more complicated buildings, or buildings that fail using the Simplified Method. Part O is based on the Cibse TM59 methodology for overheating in residential buildings.

Part G Water Calculations

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).

More Info

Energy Statements, Renewables Reports & Sustainability Reports

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, 10% energy demand reduction or CSH4/CSH5 Energy, we have experience of providing Energy Statements & Renewables Reports to satisfy Planning Authorities across the whole of the UK.

Compliance can be as simple as installing a small PV (Solar Photovoltaic) 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.

More Info

Air Tightness Testing (aka Air Pressure Testing, Air Permeability Testing)

Air Tightness 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.

More Info

Sound Testing (Part E Acoustic Testing)

New dwellings that are attached to each other (flats, semi-detached, terraces) will require Part E Sound Testing to show compliance with Part E.

Sound testing through party walls and party floors is conducted using sound meters to show compliance.

More Info

Code for Sustainable Homes (CSH)

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.