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Sap Calculations Bexley

Need Sap calculations for either Part L1A, or Part L1B, we are here to help. E mail us for a quote for your project.

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So, Just What Are Sap Calculations

For anyone who is reading this, you’ve more than likely recently been requested by someone, typically your building control official, to supply sap calculations for your building project. But you probably haven’t been told what sap calculation actually are and why you need them.

You can click on the video recording on this page, where Andreas will shed some light on this, or read on.



Bexley SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Bexley SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Bexley SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP stands for Standard Assessment Procedure and it is the united kingdom government’s method of determining the energy efficiency of dwellings. Sap calculations are necessary to demonstrate that a building conforms with specific energy targets set down in the building regulations.

In a brief overview, that’s basically it.


When Are SAP Calculations Needed?

Sap calculations usually are required for three main reasons

1. For all newly built homes
2. For a dwelling that’s changed its use,e.g altering a single family home to residential flats.
3. For extensions that have over 20% glazing

The sap calculations are necessary to establish that the dwelling emission rate (DER) and the dwelling fabric energy efficiency (DFEE) comply with specific targets.

A good set of building plans will need to be provided to the Assessor, because all the calculations are done from the building plans ,so there is no need to visit the property. Your Assessor will advise you of precisely what is needed. Once the calculations are completed, an Energy Performance Certificate or EPC can also be produced.

Your Assessor can provide you with further guidance if the calculation show your dwelling isn’t compliant, as well as advise you which would be the most effective changes to make. It can be expensive if you realise at a late phase in the construction that your building isn’t compliant. So it is wise to liaise with the Assessor as early on in the project as possible, ideally before any building commences.

Should you require guidance on a project you may have in or around , or simply require a quote, contact us or fill in our get a quote form. We’re here to help.


Need an answer to a query you might have about SAP calculations in Bexley? Here are the 10 most frequent questions.

So, Just What Are Sap Calculations

This is by far the most common question asked. Take a look at Andrea’s video explanation above, or read the full explanation here on the right.

How Much Do Sap Calculations Cost

We would be pleased to offer discount rates, in particular for multiple dwellings which are of the same or very similar design. For single properties then you would be looking in the region of £120 – £300 dependant upon the complexity of the construction and also the dimensions. By providing the plans, it will be possible to get a fixed price quote.

What’s The Difference Between Sap and EPC

Before we get to the differences, here is what you will require depending on your project.

For a new build property you’ll need – SAP calculations and an EPC.

For dwelling change of use or conversion you’ll need – Sap Calculations and an EPC.

For overglazing on an existing dwelling you’ll – Sap calculations only.

SAP or Standard Assessment Procedure are the calculations of pre defined data set of a buildings design that’s put together to show the energy efficiency of a building. EPC stands for Energy Performance Certificate and it’s a summary report of the SAP calculations in an simple to comprehend report, that can also be used to sell or rent a property.

There are actually 2 types of EPCs. The first is a SAP EPC which is produced from building plans when all the elements of the building are known. This will normally be required by building control to demonstrate that the dwelling satisfies specific targets required by the building regulations. Building control would also need to see the SAP calculations which shows in greater detail whether all the elements going into the property comply with the building regulations.

The 2nd form of EPC is the standard one that would be required for anyone who is selling, or renting out a property. This type of EPC uses what’s called rdSAP, which stands for Reduced Data Standard Assessment Procedure, which is used where specific thermal values of, for example, the walls, roof, floors, etc, are not precisely known on an established property. In this situation assumed thermal values are used based on the age of the property. This particular EPC will be no good to demonstrate compliance with any building regulations. Sometimes building control would simply ask you to get an EPC, however what they would really need are the Sap calculations (which is the data behind the EPC) and the SAP EPC (which is actually summary report of the Sap calculations).

Still perplexed, after that call us for further advice.

What Are As Built SAP Calculations

These will be the final set of SAP calculations produced after the dwelling has been completed to confirm that it is compliant with Part L1A of the building regulations. Ahead of the project starting, it ought to have had some “Design Sap” calculations to demonstrate that the proposed construction, on paper at least, will be compliant with Part L1A.



Can I Do The Sap Calculation Myself

No, this is not some thing that can be done by yourself. The calculations have to be done by an On Construction Domestic Energy Assessor or OCDEA, using approved Government computer software. The Assessor needs to be certified under one of the certification schemes and is regularly audited to keep their certification.

What Information is Required For Sap Calculations

Your Assessor would advise you of exactly what is needed. Typically you would need the following:

  • Floor Plans to include sections and elevations
  • Orientation of the property
  • Construction specification of walls, roof and floors
  • Specification for all doors and windows
  • Primary and secondary heating
  • Provision for providing  hot water
  • Any renewable technology (if any)


Sap Calculations For New Build

Every new dwelling need Sap calculations to demonstrate compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regulations.


Sap Calculations For Extensions

It’s now trendy to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. However with the current building regulations the quantity of glazing can be a maximum of 25percent of the floor area of the new extension. Therefore over compensations on the thermal elements in other areas within the property will have to be made to demonstrate that the CO2 emissions from the existing house along with the proposed extension is not any worse than the existing house and an extension where the glazing is within the permitted amount judged against Part L1B of the building regulations.

You will require SAP calculations to find solutions and demonstrate compliance.


Sap Calculations For Conversions

For anyone who is altering the use of a dwelling, you will require Sap calculations. {The new dwelling will have to comply with Part L1B of the building regulations.}


Do I Need to have Sap Calculations

You will need Sap calculations for any of the following: 

  • Building a new property
  • Changing the use of an existing property (e.g, a barn conversion, commercial building to residential)
  • Extensions with more than 25% glazing
  • Opening up the main house to an existing conservatory
  • Extension where the extension is more than 50% of the original property wall area
  • Garage conversions
  • If requested by building control

This checklist is not exhaustive. If you’re unsure whether you require them, then contact us.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully certified and accredited with many years practical experience carrying Sap calculation in Bexley . We also cover the whole of the UK and can help on any project nationwide.

Reliable & Fully Insured

You will be assigned a dedicated Assessor who is also covered by full professional indemnity insurance of up to £100,000 and that means you know you’re in save hands.

Prompt Service

We’ll respond to your enquiry within 24 hours. We’ll also help you to deliver your project within your timescale.

Satisfaction Guaranteed

We aim to provide 100% customer satisfaction and look forward to working with you.


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