Bespoke PSI (Ψ) Value Calculations assess heat loss at junctions between different building elements and provide project-specific thermal bridging values for use in energy assessments such as SAP.
We provide bespoke PSI Value Calculations for architects, developers, housebuilders, contractors and construction professionals, helping project teams accurately assess thermal bridging, improve the performance of their building design and support Building Regulations Part L compliance.
A PSI value (Ψ-value) measures the linear thermal transmittance of a junction where two building elements meet, such as a wall and floor, wall and roof or window and wall.
Unlike a U-value, which measures heat transfer through an area of a building element, a PSI value measures additional heat loss along a junction. PSI values are expressed in W/m·K.
Our calculations can assess junctions including:
• The calculated values can then be provided to the relevant energy assessor for inclusion in the SAP or other applicable energy assessment.
Thermal bridging contributes to the overall heat loss of a building and can have a significant effect on its energy performance.
Bespoke PSI Value Calculations can help you:
• Use thermal bridging values based on your actual construction details
• Improve the accuracy of your SAP assessment
• Identify junctions where heat loss can be reduced
• Support compliance with Building Regulations Part L
• Reduce reliance on conservative default values where project-specific calculations are appropriate
Assessing thermal bridges during design also gives architects and developers an opportunity to improve junction details before construction begins.
We work with architects, developers, contractors, housebuilders and construction professionals, providing design and build compliance services across residential and commercial projects.
From SAP Calculations and SBEM Assessments to air pressure testing, acoustic testing, ventilation and thermal performance assessments, we provide the technical compliance services your project needs at different stages of design and construction.
With one company and one point of contact, we make it easier to manage multiple compliance requirements from design through to completion, helping your project stay on track and meet applicable Building Regulations.
Our calculations are carried out with reference to:
• Building Regulations 2010 – Part L
• Approved Document L, Volume 1: Dwellings
• Standard Assessment Procedure (SAP)
• BS EN ISO 10211 – Thermal bridges in building construction
• BR 497 – Conventions for calculating linear thermal transmittance and temperature factors
Whether you require a Bespoke PSI Values on its own or alongside other compliance services, we’ll help coordinate the process through one trusted provider, making property compliance simpler to manage.
Our competent surveyors carry out Bespoke PSI Values across a wide range of commercial and residential properties, ensuring each survey is appropriate for the building and its intended use.
Based in Manchester with a particular focus on Greater Manchester and the wider North West. But our team supports clients across the UK, so wherever your properties are located, we’re ready to help.
Our compliance reports are written in plain English, with clear findings, practical recommendations and documentation that’s ready to use. No unnecessary jargon, just reports that help you act quickly and stay compliant.
From your first enquiry to your final report and beyond, we’re committed to clear communication, prompt responses and proactive recommendations and reminders to help you stay compliant without the stress.
We coordinate your compliance services in one place, reducing administration, saving time and making property compliance easier to manage, so you can focus on supporting your residents.
Working with the Compliance Company is always great, they produce their work in a timely and professional manner.
Communication is always top notch too, which is really appreciated. They are our go to consultants for anything Part L or SBEM related.
Very happy with their prompt noise survey and report. All done smoothly and within the timescales communicated during quotation. Highly recommended!
Ryan was exceedingly helpful. A wealth of guidance, advice, and wisdom. Very personable, professional, and honest. He answered all my questions promptly and thoroughly.
It’s very refreshing when you don’t have to chase people! Really cannot recommend Ryan enough. He and his business are top-notch
We provide Bespoke PSI Values across the UK, supporting commercial property owners, landlords, housing providers, managing agents, contractors and organisations responsible for maintaining safe, compliant buildings.
Our surveyors regularly work across:
• Greater Manchester (Manchester, Salford, Bolton, Stockport, Oldham, Rochdale, Bury, Tameside, Trafford, Wigan)
• Merseyside (Liverpool, Wirral, St Helens, Southport, Knowsley, Sefton)
• Cheshire (Chester, Warrington, Crewe, Macclesfield, Northwich, Ellesmere Port, Wilmslow)
• Lancashire (Preston, Blackburn, Blackpool, Burnley, Accrington, Rossendale, Chorley, Lancaster)
• West Yorkshire (Leeds, Bradford, Wakefield, Huddersfield, Halifax, Dewsbury, Batley)
• South Yorkshire (Sheffield, Doncaster, Rotherham, Barnsley)
• North Yorkshire (York, Harrogate, Scarborough, Ripon, Selby, Skipton)
• East Midlands (Derby, Nottingham, Leicester, Derbyshire, Nottinghamshire, Leicestershire)
• Staffordshire (Stoke-on-Trent, Stafford, Tamworth, Newcastle-under-Lyme, Burton upon Trent)
• West Midlands (Birmingham, Coventry, Wolverhampton, Solihull, Walsall, Dudley, Sandwell)
• North East (Newcastle, Sunderland, Gateshead, Middlesbrough, Darlington, Durham)
• East Anglia (Cambridge, Norwich, Ipswich, Peterborough)
• Greater London (Central, North, South, East, West London)
• Kent (Maidstone, Canterbury, Medway, Ashford, Dartford, Tunbridge Wells)
• Surrey (Guildford, Woking, Reigate, Epsom, Redhill)
• Essex (Chelmsford, Colchester, Basildon, Southend-on-Sea, Harlow)
• South Coast (Hampshire, Sussex, Portsmouth, Southampton, Brighton, Eastbourne)
• South West (Bristol, Devon, Cornwall, Somerset, Gloucestershire, Plymouth, Exeter, Bath, Gloucester, Cheltenham, Taunton)
• South Wales (Cardiff, Newport, Swansea, Bridgend, Merthyr Tydfil)
• Scotland (Glasgow, Edinburgh, Aberdeen, Dundee, Stirling, Perth)
Bespoke PSI calculations are not legally required for every new dwelling. However, Building Regulations require thermal bridging to be accounted for in the energy assessment, and we recommend bespoke PSI calculations for new-build projects where accurate, project-specific thermal bridging values are beneficial.
Bespoke calculations assess the actual construction details rather than relying on default or reference values. This can provide a more accurate SAP assessment and may help improve the overall energy performance of the dwelling.
Not necessarily. If the SAP assessment meets the applicable requirements using permitted thermal bridging values, bespoke PSI calculations may not be required. However, project-specific PSI values can provide a more accurate representation of the actual junctions and may improve the SAP result where the calculated junctions perform better than the values otherwise used.
We typically need scaled construction details, dimensions, material specifications, insulation arrangements and information about the adjoining building elements. The more detailed and accurate the construction information, the more representative the thermal model will be.
Potentially, yes. Where the same construction detail is used across multiple plots or house types, a calculated PSI value may be applicable to each instance of that same detail, provided the construction and relevant assessment conditions are consistent.
Ideally, thermal bridging should be considered during the design stage, alongside the development of the building fabric and construction details. This gives the design team an opportunity to improve junctions before the construction specification is finalised.
Yes. We can provide PSI Value Calculations alongside SAP Calculations where required, giving architects, developers and housebuilders a convenient way to coordinate thermal bridging and energy performance requirements.
Learn more about our SAP Calculations.
New homes need to demonstrate compliance with the energy efficiency requirements of Part L of the Building Regulations. SAP calculations assess the energy performance of a dwelling and help determine whether the proposed design meets the required standards.
We provide SAP calculations for new-build and conversion projects, assessing energy performance, carbon emissions and key building specifications, and provide the reports needed for Building Control and compliance.
Non-domestic buildings need to demonstrate compliance with the energy efficiency requirements of Part L of the Building Regulations. SBEM assesses the energy performance of buildings such as offices, retail units and commercial spaces against the required standards.
We provide SBEM assessments for new-build and commercial projects, modelling energy performance, carbon emissions and building specifications, and providing the reports needed for Building Control and compliance.
Overheating can affect comfort, health and the performance of new homes. Under Part O of the Building Regulations, new residential buildings must be designed to reduce the risk of overheating and provide adequate means of removing excess heat.
We carry out Part O overheating assessments using the Simplified Method or Dynamic Thermal Modelling, providing clear results and compliance documentation for your project.
Whether you’re managing a residential property, supported accommodation, office, school or commercial premises, an EPC provides an A–G energy efficiency rating and recommendations for improvement.
EPC requirements apply to many properties when they are constructed, sold or rented, with Minimum Energy Efficiency Standards (MEES) also applying to certain rented properties.
We carry out EPC assessments and provide the certification and information you need to understand your property’s energy performance and meet applicable requirements.
Energy performance needs to be considered early in the design process, particularly where planning requirements call for a clear strategy for reducing energy use and carbon emissions.
We prepare energy statements for residential and commercial developments, assessing energy demand, efficiency measures and low-carbon technologies to demonstrate how a project meets its energy and sustainability targets.
New homes need to demonstrate that their water use meets the requirements of Part G of the Building Regulations. Our water efficiency calculations assess the proposed fittings and appliances against the required litres-per-person-per-day target.
We calculate water consumption for new dwellings, helping you meet the required 125-litre or optional 110-litre standard and providing the documentation needed for Building Control.
Air leakage can affect a building’s energy performance and its compliance with Part L of the Building Regulations. For new dwellings, air pressure testing is an important part of demonstrating that the required standards for air permeability have been met.
We carry out accurate air pressure tests, identify air leakage and provide the certification and reporting needed for building control.
Poor sound insulation can affect comfort, privacy and compliance in residential developments. Under Part E of the Building Regulations, buildings must provide appropriate resistance to the passage of sound.
We carry out airborne and impact sound testing to assess acoustic performance, identify issues and provide the test results and reporting needed for building control.
Is the ventilation system actually delivering the airflow it was designed for? Our testing checks MEV, MVHR and other mechanical ventilation systems at individual terminals, helping identify performance issues before they hold up sign-off.
We provide accurate flow-rate results and the certification needed to demonstrate compliance with Part F of the Building Regulations.
Compliance in supported housing is a different beast.
It has stricter frameworks, sector-specific requirements and a very different set of responsibilities.
We have a specialist division built entirely for it. Same one-stop-shop approach, built specifically for housing providers, care organisations and nominated individuals managing property compliance.
