Factsheet: Information Gathering

Building information required by a design team to develop a decarbonisation plan.

Published 30 October 2025

This factsheet provides an overview of the different types of information required to support the production of a decarbonisation plan, based on stage 1 of the whole building approach.

The background data and survey information required to support a decarbonisation plan includes all aspects of the building and it's setting that may impact the appropriateness, effectiveness or longevity of potential interventions to mitigate or adapt to climate change.

Interventions to a historic building for energy efficiency and/or climate resilience should be considered as part of a thorough understanding of the building in its context. Collating background data and surveys enables the subsequent design and planning stages to respond to specific opportunities and constraints through robust risk-based assessment. This ensures that proposed interventions:

Are appropriate, proportionate, effective, and cost-efficient.
Account for the building's context, including climate change risks.
Prioritise occupant and building health.
Avoid harm to the significance of the building.

It also allows the impact, efficacy, and cost efficiency of interventions to be predicted, measured, and monitored at various stages of the project.

Whole Building Approach: Stage 1

This webpage outlines best practice for assimilating data and surveys as Stage 1 of the whole building approach.

Define objectives and scope

Decarbonisation strategies may be commissioned for different reasons, and the extent and nature of data gathered and surveys undertaken should always be proportionate to the complexity and significance of the building or site and the individual project objectives. These should be established through a robust client brief and project scoping exercise outlining:

The project circumstances, requirements, aspirations and aims.
Available resources: financial, skills, materials.
Timescales and quality of work required.

The scope of data gathering and surveys can then be informed by the elements essential to meet the project objectives, considering what is feasible within the specific circumstances and available resources.

Gather data and surveys

The background data and survey information required to support a decarbonisation plan includes all aspects of the building and its setting that may impact the appropriateness, effectiveness or longevity of potential interventions to mitigate or adapt to climate change. They include:

Regulations and statutory context, including Heritage, Planning and Building Regulations.
Topography and site conditions, including location, exposure, and vulnerability.
Building context, including scale and form, significance, construction, condition, services, and energy performance.
Use, occupancy, and management.

Methods used to gather data and surveys can range from desktop research and site observations to more detailed quantitative analysis that include site surveys and investigations and computer simulations. Although building owners can provide useful contextual information, suitably qualified, experienced, independent practitioners can provide a more holistic output.

How to find required information

Regulatory & Statutory Context

Background Data	Relevance to Decarbonisation Planning	Methodology
Heritage designations	Buildings or structures within the site that are nationally designated (listed, scheduled or within a registered park and garden) have special protections and may require listed building consent or scheduled monument consent for works associated with decarbonisation.	Desktop research: Identify heritage designations by searching the National Heritage List for England (NHLE).
	If a building is in a conservation area, permitted development rights are restricted and planning permission may be needed. Other heritage designations, such as registered parks and gardens, require the local planning authority to consider heritage issues when making decisions on planning applications.	Desktop research: check with the local planning authority.
Planning	Previous works and/or the presence of restrictive covenants may affect the planning and design of energy efficiency measures	Desktop research: Research the local planning policy context, as well as previous planning applications via the Planning Portal, local planning departments, estate archives and records, and diocesan or cathedral archives. Restrictive covenants or easements related to the site can be checked via the government's property information service
Ecology	Protected trees: A Tree Preservation Order (TPO) is an order made by a local planning authority in England to protect specific trees, groups of trees or woodlands in the interests of amenity.	Desktop research: Identify whether there are any protected trees, species or ecological habitats within the site - check with the local planning authority
	Protected species: The presence of protected species on a site or within a building may impact opportunities to improve energy efficiency and climate resilience, or the timing of works.	Desktop research: An ecologist can undertake a desk-based preliminary scoping survey to establish the potential the site has to support any protected species and whether a preliminary site survey is needed. You can find a qualified ecologist using the Chartered Institute of Ecology and Environment Management (CIEEM) directory.
Neighbourly constraints	Site constraints with regards to neighbouring occupiers, such as Party Walls and potential Rights of Lights issues, may impact potential decarbonisation measures.	Desktop research: Identify any site constraints with regards to neighbouring occupiers as part of an initial site appraisal by the professional team.
Building regulations	Potential decarbonisation measures may be subject to building regulations approval, including: Part B - Fire Safety Part L - Conservation of Fuel and Power.	Desktop research: The professional team should summarise the regulatory context as part of the initial project assessment.

Topography & Site Conditions

Background Data	Relevance to Decarbonisation Planning	Methodology
Site topography and hydrology	Topography and site conditions may affect the vulnerability of the building and its occupants to different hazards, such as contaminants, structural issues, overheating or flooding. An initial desk-based review may identify, where appropriate, site level and layout information, determine the locations of water courses, drainage and utilities. This may also identify potential water sources for grey water systems or low or zero carbon technologies and opportunities to reduce water scarcity.	Desktop research: Review local topography and hydrology through online maps as well as previous reports or remediation certificates.
Site geology	Past structural surveys or reports should identify if the building is susceptible to subsidence or heave. They will also give a better understanding of the underlying geology to inform risk assessments.	Desktop research: Identify structural risks associated with site geology: The British Geological Survey has free tools that can be reviewed, such as the BGS Geology Viewer and BGS GeoIndex.
Site location and exposure	The location, aspect and exposure of individual elevations all influence a building's hygrothermal performance and the types of interventions that may or may not be suitable.	Desktop research: Identify site constraints such as location, exposure and building orientation Review site exposure and vulnerability, informed by the Met Office climate maps and data.
Site contaminants and hazardous materials	Buildings and sites may include hazardous materials such as asbestos, radon, and soil contaminants, which may impact retrofit decisions.	Desktop research: As part of the initial site assessment, the lead consultant (architect, building surveyor or MEP engineer) should collate known information and identify further surveys required. Consult the UK radon maps for further information. Review information on ground conditions and contaminants through the Coal Authority interactive map viewer. External air quality can be investigated using the DEFRA Air Information Resource and the DEFRA Smoke Control Area Map.
Site utilities and below ground services		Desktop research: Review local utilities information and maps, and any previously commissioned below ground services surveys.

Building Context

Background Data	Relevance to Decarbonisation Planning	Methodology
Building form	Scaled drawings are required to establish the overall layout, dimensions, external form and characteristics of the building. These also enable robust calculations of heat loss areas and ventilation requirements.	Site Survey: Obtain or commission a measured survey of the building. Ideally this would include a topographical (landscape) survey; measured building plans, sections and elevations.
Building significance	An assessment of significance is required to identify aspects of the building's heritage significance that may be affected by proposed works, including: - External features, such as building materials, windows, doors, doorcases, eaves or cornices, that contribute to the architectural and aesthetic qualities of the building. - Interior features, such as historic plasterwork, fireplaces, cornices, doorcases, panelling and window shutters, that contribute to the historical and architectural interest of the building. - Structural elements of historic importance, such as roof and floor structures. - The overall ‘hierarchy of significance’ identifying areas of particular significance, which are more sensitive to change, and areas of lesser significance, where a greater degree of change could be accommodated.	Desktop research and site survey: Undertake an assessment of significance. This should be carried out by a Heritage expert or architect with demonstrable experience in the conservation of historic and listed buildings. It will include both desktop research and site visits and may be summarised in the form of a brief Heritage Statement, with drawings illustrating the ‘Hierarchy of Significance’ across the building or site.
Building construction	Identifying the building’s construction helps with understanding the building's moisture and thermal properties (hygrothermal performance), suitability for intervention, and inform appropriate material choices. You should consider: - Age(s) - Construction type, structure, and materials - Building phases and the attachment to other dwellings or buildings - Building detailing or architectural features (including differences between building phases) - Location and type of previous alterations or energy efficiency measures already installed	An architect or building surveyor commissioned to help produce a decarbonisation plan can identify the key characteristics of the building’s construction through: Desktop research: Review of published and archival information on the history of the building and phases of construction. Site visit: Visual inspection of the building to establish the nature of construction and primary materials used.
Building condition	Prioritising repair and maintenance are essential and should be regarded as the primary measure in any energy efficiency project. This not only stops the building falling into disrepair, but also means that the efficacy of interventions will not be undermined and risks to buildings and fabric reduced. A condition survey should be undertaken to establish the location and severity of any existing defects. It should provide a schedule of repairs that need to be carried out prior to installing any mitigation or adaptation interventions.	Site Survey: Condition surveys involve site inspections including visual assessments of condition, and if required, further testing of building defects such as water penetration and damp, timber rotting and decay. A visual inspection may be carried out by an architect with demonstrable experience and competency in this area, or by a Chartered Building Surveyor registered with an appropriate professional body such as RICS.
Building services	A survey of existing services and systems helps to establish the size, capacity, and loadings of the incoming utility services, as well as the type, age and condition of heating, cooling, hot water, ventilation, lighting and power distribution systems, plus electrical panels, switchgear, and any other equipment. This will also help to establish the delivered energy demand and measure building performance. Depending on the scale and nature of the building, a separate ventilation assessment may be required to determine the existing provision and inform design requirements. The removal and replacement of services must be done in a way that limits damage to the historic fabric of the building.	Part 1: Desk-top research - Obtaining services record drawings. These may be kept in operation and maintenance manuals or an archive. - Looking for testing and inspection reports such as electrical, gas and mechanical systems reports. - Collating information on incoming supplies and electricity, gas and water usage. - Checking the asbestos register for the property. - Collating any environmental monitoring data such as temperature and humidity records (may be recorded as part of a Building Management System / BMS). - Reviewing asset registers, which are lists of all the services in the building used by maintenance staff. Part 2: site survey - Visually assessing the condition of the systems and components. - Verifying the accuracy of the record drawings is correct. - Assessing if any services can be retained and reused. - Assessing the heritage significance of the systems. - Reviewing the capacity of the current systems. - Identifying maintenance issues including access constraints for maintenance, replacement or new work. - Identifying hazards. - Carrying out building performance inspections such as thermal imaging, load monitoring.
Building performance	Gather robust objective data on building performance is fundamental to identifying the accurate energy performance baseline of a building. The scope and comprehensiveness of any building performance survey should be proportionate to the significance of the building and the project’s objectives. It should consider what is feasible within the specific circumstances and available resources.	Desktop research: Initial energy audits can be achieved by reviewing previous energy bills or smart meter data to estimate annual energy use. Site Survey: A range of non-destructive tests can also be carried out to assess the thermal performance and moisture content of the building envelope, such as: - Air pressure testing - Infrared thermography - U-value measurement - Heat loss coefficient testing or calculations - Temperature, humidity and CO2 readings - Hygrothermal assessment modelling and analysis

Background Data

Relevance to Decarbonisation Planning

Methodology

Building form

Scaled drawings are required to establish the overall layout, dimensions, external form and characteristics of the building.

These also enable robust calculations of heat loss areas and ventilation requirements.

Site Survey:

Obtain or commission a measured survey of the building. Ideally this would include a topographical (landscape) survey; measured building plans, sections and elevations.

Building significance

An assessment of significance is required to identify aspects of the building's heritage significance that may be affected by proposed works, including:

- External features, such as building materials, windows, doors, doorcases, eaves or cornices, that contribute to the architectural and aesthetic qualities of the building.

- Interior features, such as historic plasterwork, fireplaces, cornices, doorcases, panelling and window shutters, that contribute to the historical and architectural interest of the building.

- Structural elements of historic importance, such as roof and floor structures.

- The overall ‘hierarchy of significance’ identifying areas of particular significance, which are more sensitive to change, and areas of lesser significance, where a greater degree of change could be accommodated.

Desktop research and site survey:

Undertake an assessment of significance. This should be carried out by a Heritage expert or architect with demonstrable experience in the conservation of historic and listed buildings.

It will include both desktop research and site visits and may be summarised in the form of a brief Heritage Statement, with drawings illustrating the ‘Hierarchy of Significance’ across the building or site.

Building construction

Identifying the building’s construction helps with understanding the building's moisture and thermal properties (hygrothermal performance), suitability for intervention, and inform appropriate material choices. You should consider:

- Age(s)

- Construction type, structure, and materials

- Building phases and the attachment to other dwellings or buildings

- Building detailing or architectural features (including differences between building phases)

- Location and type of previous alterations or energy efficiency measures already installed

An architect or building surveyor commissioned to help produce a decarbonisation plan can identify the key characteristics of the building’s construction through:

Desktop research:

Review of published and archival information on the history of the building and phases of construction.

Site visit:

Visual inspection of the building to establish the nature of construction and primary materials used.

Building condition

Prioritising repair and maintenance are essential and should be regarded as the primary measure in any energy efficiency project. This not only stops the building falling into disrepair, but also means that the efficacy of interventions will not be undermined and risks to buildings and fabric reduced.

A condition survey should be undertaken to establish the location and severity of any existing defects. It should provide a schedule of repairs that need to be carried out prior to installing any mitigation or adaptation interventions.

Site Survey:

Condition surveys involve site inspections including visual assessments of condition, and if required, further testing of building defects such as water penetration and damp, timber rotting and decay.

A visual inspection may be carried out by an architect with demonstrable experience and competency in this area, or by a Chartered Building Surveyor registered with an appropriate professional body such as RICS.

Building services

A survey of existing services and systems helps to establish the size, capacity, and loadings of the incoming utility services, as well as the type, age and condition of heating, cooling, hot water, ventilation, lighting and power distribution systems, plus electrical panels, switchgear, and any other equipment.

This will also help to establish the delivered energy demand and measure building performance.

Depending on the scale and nature of the building, a separate ventilation assessment may be required to determine the existing provision and inform design requirements.

The removal and replacement of services must be done in a way that limits damage to the historic fabric of the building.

Part 1: Desk-top research

- Obtaining services record drawings. These may be kept in operation and maintenance manuals or an archive.

- Looking for testing and inspection reports such as electrical, gas and mechanical systems reports.

- Collating information on incoming supplies and electricity, gas and water usage.

- Checking the asbestos register for the property.

- Collating any environmental monitoring data such as temperature and humidity records (may be recorded as part of a Building Management System / BMS).

- Reviewing asset registers, which are lists of all the services in the building used by maintenance staff.

Part 2: site survey

- Visually assessing the condition of the systems and components.

- Verifying the accuracy of the record drawings is correct.

- Assessing if any services can be retained and reused.

- Assessing the heritage significance of the systems.

- Reviewing the capacity of the current systems.

- Identifying maintenance issues including access constraints for maintenance, replacement or new work.

- Identifying hazards.

- Carrying out building performance inspections such as thermal imaging, load monitoring.

Building performance

Gather robust objective data on building performance is fundamental to identifying the accurate energy performance baseline of a building.

The scope and comprehensiveness of any building performance survey should be proportionate to the significance of the building and the project’s objectives. It should consider what is feasible within the specific circumstances and available resources.

Desktop research:

Initial energy audits can be achieved by reviewing previous energy bills or smart meter data to estimate annual energy use.

Site Survey:

A range of non-destructive tests can also be carried out to assess the thermal performance and moisture content of the building envelope, such as:

- Air pressure testing

- Infrared thermography

- U-value measurement

- Heat loss coefficient testing or calculations

- Temperature, humidity and CO2 readings

- Hygrothermal assessment modelling and analysis

Use, Occupancy & Management

Background Data	Relevance to Decarbonisation Planning	Methodology
Occupancy	Understanding how the building is used and occupied is an important part of assessing its current energy demands, as well as the energy performance standards that need to be considered during the planning and design stages. The way a building is managed, its occupancy levels and hours, building use patterns, and the type of activity undertaken there can have great bearing on appropriate interventions, energy use and the perception of thermal comfort for users. Reorganising spaces may lower energy use. If possible, identify where spaces can be reordered easily to best accommodate different seasons. Factors normally considered include temperature, humidity, natural light, ventilation provision and access. For example, consider moving offices out of loft spaces that are prone to summertime overheating, or habitable accommodation out of basements where winter temperatures, low light levels, and damp may create uncomfortable conditions or unnecessary energy use.	Desktop research and site visit: Colour-coded plans identifying different types of use can be a useful tool to illustrate the arrangement of activities within the building.
Occupant Engagement	Occupant engagement is also a contributing factor. There can be considerable variations in energy use from one building to another.	Briefing meetings: Data gathering should also include interviews with building managers and/or users to find out how they use (or plan to use) the building. It should establish if there are any special considerations, including if the building is used by vulnerable people, such as the elderly or those with additional needs. It will also help to understand if there are currently problems with thermal comfort in the building – such as rooms that are too cold in winter, too hot in summer, or are considered stuffy or prone to draughts. It may be useful to walk around with the owner, facilities manager, operations manager, or other interested party to identify any site constraints from an operational perspective.

Background Data

Relevance to Decarbonisation Planning

Methodology

Occupancy

Understanding how the building is used and occupied is an important part of assessing its current energy demands, as well as the energy performance standards that need to be considered during the planning and design stages.

The way a building is managed, its occupancy levels and hours, building use patterns, and the type of activity undertaken there can have great bearing on appropriate interventions, energy use and the perception of thermal comfort for users.

Reorganising spaces may lower energy use. If possible, identify where spaces can be reordered easily to best accommodate different seasons. Factors normally considered include temperature, humidity, natural light, ventilation provision and access. For example, consider moving offices out of loft spaces that are prone to summertime overheating, or habitable accommodation out of basements where winter temperatures, low light levels, and damp may create uncomfortable conditions or unnecessary energy use.

Desktop research and site visit:

Colour-coded plans identifying different types of use can be a useful tool to illustrate the arrangement of activities within the building.

Occupant Engagement

Occupant engagement is also a contributing factor. There can be considerable variations in energy use from one building to another.

Briefing meetings: Data gathering should also include interviews with building managers and/or users to find out how they use (or plan to use) the building. It should establish if there are any special considerations, including if the building is used by vulnerable people, such as the elderly or those with additional needs.

It will also help to understand if there are currently problems with thermal comfort in the building – such as rooms that are too cold in winter, too hot in summer, or are considered stuffy or prone to draughts.

It may be useful to walk around with the owner, facilities manager, operations manager, or other interested party to identify any site constraints from an operational perspective.

Factsheet: Information Gathering

Define objectives and scope

Gather data and surveys

How to find required information

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