Partner Services

Building Consents work in partnership with One Stop Consult to provide wide range of additional services and supply chain partners for both residential property developers and commercial operators.

Design Services

  • Phase 1 Desk Study
  • L1A New Build SAP Calculations

    SAP calculations for New Build Dwellings come in two stages: a ‘design stage’ SAP report and an ‘as built’ SAP report. These calculations will measure a number of aspects of the building’s energy performance. The building needs to be designed to comply with the SAP targets in terms of Energy Performance, Carbon footprint and conforming to the relevant carbon emission targets depending on the on the local authority requirement geographically. It is a building regulation requirement to provide SAP calculations prior to commencement on site. If the designed building is failing the SAP calculations, our team can advise you on how get this to work in the most cost-effective manner.

    SAP Calculations involve:

    • Assessing the area of the external building fabric and openings.
    • Analysing the building’s construction materials.
    • Understanding the energy consumption of the heating systems, lighting, ventilation systems and renewable technologies.

    Inputting this data into SAP calculations software in order to produce Target Emissions Rates (TER) measurements, Target Fabric Energy Efficiency measurements (TFEE) and to demonstrate that the building is Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE) compliant.

  • L1B Conversion SAP Calculations

    L1B SAP calculations for conversions come in two stages: a ‘notional report’ and a ‘proposed report’. These reports are then compared in order to produce an up-to-date EPC for the property.

    This process includes:

    • Assessing the existing and proposed area of the external building fabric and openings.
    • Analysing the building’s current construction materials and the extension’s proposed materials.
    • Understanding the energy consumption of the current and updated heating systems, lighting, ventilation systems and renewable technologies.
    • Creating a report with benchmarked data for the existing and proposed elements of the building, and a report with the proposed data for the existing building and the extension.
    • Inputting data from the proposed report into SAP calculations software. This determines the entire property’s Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE) rating.
    • The DER and DFEE of the proposed report is then compared against benchmarked standards. For conversions to pass the SAP calculations process, the figures from the proposed report must be lower than the benchmarks.

    One Stop Consult can arrange these calculations within 7 working days from instruction.

  • L2A SBEM Calculations

    SBEM calculations come in two stages: a ‘design stage’ SBEM report and an ‘as built’ SBEM report. The primary purpose of these calculations is to produce the EPC.

    SBEMs are designed to assess and compare energy in non-residential buildings. Nearly all new non-domestic buildings require an SBEM prior to construction and it is normally a requirement of Building Control at this early stage.

    SBEM is a computer programme that provides an analysis of a building’s energy consumption, including monthly energy use and carbon emissions. This was developed for the Department for Communities and Local Government (DCLG) to partially satisfy the requirements of the Energy Performance of Buildings Directive (EPBD).

  • L2B SBEM Calculations

    Part L2B SBEM Calculations – Non-Domestic Refurbishment & Extensions

    SBEM (Simplified Building Energy Model) provides an analysis of the energy consumption of buildings other than dwellings; it is used in support of the National Calculation Methodology and the Energy Performance of Buildings Directive. A SBEM is required for all new building and extensions which are in excess of 100m2 and more than 25% of the original building. SBEM’s are used to show compliance with Part L Approved Documents L2A and L2B of The Building Regulations 2000 (as amended).

    If you are extending a commercial building 100m2 and it is more than 25% of the original building then an L2B SBEM calculation will be required by building control.

    We have extensive experience in this area and can help to comply with the regulation whilst also being cost conscious as

  • Water Usage Calculations

    Water efficiency calculations predict water consumption in line with Part G of The Building Regulations. You need these calculations for all new builds, as well as some conversions. The water efficiency of a property is becoming increasingly important to make homes more sustainable. Furthermore, as the population grows, it is more important that water is conserved.

    Water efficiency is measured in litres per person. To comply with Part G of The Building Regulations, a property must show that its water targets will not exceed 125 litres per person per day. Some local authorities will set lower targets, especially in London and the South. For more information about these regulations, visit our section on The London Plan.

  • Part O - What You Need To Know

    Part O of the 2021 Building Regulations has been introduced to tackle overheating in residential buildings.

    Its aim is to mitigate overheating through unwanted solar gains and promote design that provides adequate means of removing excess heat from the indoor environment. It does not guarantee the comfort of residents but protects the health and welfare of occupants of the building by reducing the occurrence of high indoor temperatures.

    Does Part O apply to your building?

    Part O applies to all new residential buildings in England & Wales including dwellings, institutional buildings (i.e. schools or other similar establishments) where people sleep on the premises, and multi-use residential buildings (such as student accommodation). Please note that shared communal rooms and common spaces of buildings containing more than one residential until fall within the scope of Part O, as well as live/work units that contain both living and space for commercial purposes.

    Part O Overheating Calculations with UKBC

    There are two options to demonstrate Part O compliance.

    Overheating Calculations: Simplified Method

    Dynamic Thermal Modelling: CIBSE TM59 Calculations

    Overheating Analysis

    The former should usually be the first resort. However, if the building fails the simplified method, then a full CIBSE TM59 assessment will be required

Building Testing & Certification

  • Sound Insulation Testing

    Residential noise and vibration surveying assess the level of noise in a residential development. If you’re planning a development in a residential area, you will need to conduct a noise survey to comply with the National Planning Policy Framework and British Standards and Good Practice Documents.

    Your local authority will usually request a residential noise and vibration survey at planning stage. This is particularly the case for any development that is highlighted as having potential to significantly increase noise level, causing disruption to existing residents. Noise and vibration surveys will simultaneously investigate all possible noise sources, whether they’re related to transport, building services or people. Furthermore, we break down the data into a timeline, to measure the potential daytime and night-time average noise levels. This is so we can better understand the acoustic footprint of the proposed development.

  • Air Tightness Testing

    One Stop Consult will provide you with a site readiness checklist to help you determine when your building is ready. Our technicians calculate air tightness via the following process:

    We’ll install a large fan, usually in a doorway.

    Next, we will temporarily seal openings to the property and switch the fan on. The air pressure is gradually increased and decreased, recording the pressure differential at each step.

    Finally, our technicians will calculate the total air flow required to achieve a pressure differential of 50 Pa, divided by the total building envelope area.

    This calculation will show leakage rate in m³/h.m² @ 50 Pa.

    Whilst we’re conducting your test, other contractors can continue work within the property. However, all windows and doors must remain closed for the duration of the test.

    If the air test fails, we do offer a sealing and guaranteed pass service. This is a good solution for handover deadlines. The price for this service is determined depending on the leakage report and size scheme.

  • Extract Ventilation Testing

    All residential new build & conversion projects forming new dwellings will require ventilation testing.

    There are 5 different ventilation types, ranging from simple background and intermittent fans, to whole house mechanical extract systems with heat recovery. These are labelled as ‘Systems 1 – 5’.

    Part F testing validates air flow measurements for the new dwelling and ensures that the system has been configured correctly. Testing should be carried out using UKAS calibrated equipment.

    All kitchen intermittent extractor fans must extract at least 30 litres of air per second. If an intermittent extractor fan in the kitchen is not adjacent to a hob, it must extract air at least 60L p/s. All continuous extraction units in the kitchen must extract at least 13L of air p/s. For bathrooms, the extraction rate of an intermittent extraction unit must extract at least 15L of air p/s, or 8L p/s for continuous extraction units.

    Intermittent extraction units in utility rooms must extract at least 30L of air p/s, or at least 8L of air p/s for continuous extraction units.

    The dwelling must have an adequate overall ventilation standard rate. This will depend on the number of bedrooms. For example, in 1-bedroom properties the overall standard ventilation rate must be 13L p/s. However, in 5-bedroom properties this rate must be 29L p/s for 5-bedroom properties.

  • Energy Performance Certificates

    What are Energy Performance Certificates (EPCs)

    Energy Performance Certificates (EPCs) are a requirement whenever a building is built, rented or sold. The EPC provides an energy performance rating of a building including energy efficiency and carbon emissions.

    Our UK-wide accredited energy assessors can evaluate proposed construction details or carry out a detailed energy survey of the building, perform the necessary energy assessment calculations (in SBEM or DSM) and generate the EPC certificate before lodging it on the Government database, Landmark.

  • Fire Risk Assessment

    Managing Fire Safety

    Good management of fire safety is essential to ensure:

    • That fires are unlikely to occur;
    • That if they do occur, they are likely to be controlled or contained quickly, effectively and safely;
    • That if a fire does occur and grow, everyone in your premises is able to escape to a place of total safety easily and quickly.

    This Fire Risk Assessment is central to good management practice in fire safety. It will help you ensure that your fire safety procedures, fire prevention measures, and fire precautions (plans, systems and equipment) are all in place and working properly, and it identifies issues that need attention.

    The aims of the Assessment are:

    • To identify the fire hazards
    • To reduce the risk of those hazards causing harm to as low as reasonably practicable
    • To decide what physical fire precautions and management arrangements are necessary to ensure the safety of people in your premises if a fire does start.

    The Assessment is an organized and methodical look at your premises, the activities carried on there, and the likelihood that a fire could start and cause harm to those in and around the premises.

    The Significant Findings and Recommendations section provides the basis for a plan to secure the necessary improvements.

    The Regulatory Reform (Fire Safety) Order 2005

    The Order replaces previous fire safety legislation. Any fire certificate issued under the Fire Precautions Act 1971 will cease to have any effect. If a fire certificate has been issued in respect of your premises or if the premises were built to recent building regulations, as long as you have made no material alterations and all the physical fire precautions have been properly maintained, then it is unlikely you will need to make any significant improvements to your existing physical fire protection arrangements to comply with the Order. However, you must still carry out a fire risk assessment and keep it up to date to ensure that all the fire precautions in your premises remain current and adequate.

    There are other fire safety duties you must comply with:

    • You must appoint one or more competent persons, depending on the size and use of your premises, to carry out any protective or preventative measures.
    • You must provide your employees with clear relevant information on the risk to them identified in the risk assessment.
    • You must consult your employees or their representative about the measures you have taken to prevent fires.
    • You must inform non-employees, such as temporary or contract workers, of the relevant risks to them, and provide them with information.
    • You must co-operate and co-ordinate with other responsible persons who have premises in the building and inform them of any significant risks you find, and how you will seek to reduce/ control those risks, which might affect the safety of their employees.
    • You must provide the employer of any person from an outside organisation who is working in your premises with clear and relevant information on the risks to those employees and the preventative measures taken.
    • You must consider the presence of any dangerous substances and the risk this presents to relevant persons from fire.
    • You must establish a means of contacting the emergency services and providing them with any relevant information about dangerous substances.
    • You must provide appropriate information, instruction, and training to your employees, during their normal working hours, about fire precautions in your workplace, initially and have regular updating/refresher training.
    • You must ensure that the premises and any equipment provided in connection with firefighting, fire detection and warning, or emergency routes and exits are covered by a suitable system of maintenance and are maintained by a competent person or company in an efficient working order and in good repair.
    • You must if employing a child provide the parent with clear and relevant information on the risks to that child in case of fire.

    Scope of the Fire Risk Assessment

    This assessment has been carried out in accordance with the Regulatory Reform (Fire Safety) Order 2005, and the appropriate Guides. The following people contributed to or are concerned parties

    The responsible person: The Registered Owner

    In summary, the assessment process was as follows:

    Fire hazards

    We identified sources of ignition (for example, electrical, gas or oil-fired heaters), sources of fuel (for example, furniture and other combustible materials left on the escape route) and potential sources of oxygen (for example, poor compart-mentation from airflow when self- closing doors are propped open).

    People at risk

    We considered where you have people working, either at permanent locations (such as workstations) or at occasional locations around the premises, and considered who else might be at risk, such as the residents, public, or visiting contractors and where these people are likely to be found. Consideration was also given to employees who work alone and/or in isolated areas, e.g., cleaners and security staff. We also considered people with disabilities or those who may have some other reason for not being able to leave the premises quickly.

    Identifying and managing the risk

    We considered the fire detection and warning systems, where fitted; the measures you have taken to control the spread of fire and to protect the means of escape; the adequacy of the emergency lighting and escape route signage; the adequacy of the provision of fire extinguishers and your arrangements for the maintenance of fire safety equipment.

    Training and records

    We assess how significant findings and recommendations are acted upon; we consider how employees and other users of the building are informed about what to do in an emergency (for example, by fire action notices). We also assess staff training arrangements where this is applicable.


    We consider how recommendations are implemented, and how the fire risk assessment is reviewed in response to changing circumstances, for example, alterations to the building, including the internal layout; problems reported by employees and visitors; and whether there are adequate arrangements for periodic review.

Get a Quote

Get a Quote