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Sap Calculations Hammersmith and Fulham

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So, Just What Are Sap Calculations

For anyone who is reading this, you’ve probably been asked by someone, normally your building control official, to provide 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 clip on this page, where Andreas will shed some light on this, or read on.



Hammersmith and Fulham SAP Calcs For Dwelling Change Of Use

  • Reports for Part L1B Compliance
  • Free Advice

Hammersmith and Fulham SAP Calcs For Overglazed Extensions

  • Carbon Emissions Reports
  • Heat Loss Calculations
  • Free Advice

Hammersmith and Fulham SAP Calcs For New Builds

  • Reports for Part L1A compliance
  • Free Advice

What does SAP mean?

SAP is short for Standard Assessment Procedure and is the UK government’s method of calculating the energy performance of dwellings. The calculations are needed to show that your building complies with specified energy targets laid down in the building regs.

As a quick overview, that’s more or less it.


When Are SAP Calculations Needed?

Here are most of the reasons you may well be asked for sap calculations

1. For extensions that have more than the permitted amount of glazing
2. For all new homes
3. For a dwelling change of use, such as

The two main areas which the sap calculations will be looking at is that the carbon emissions from your property are within set tolerances and that certain elements of the property, such as the walls, floors, roof and windows comply with certain thermal energy targets.

A good set of construction drawings will need to be provided to the Assessor, since all the calculations are done from the building drawings . Your Assessor will advise you of precisely what is needed. An EPC or Energy Performance Certificate can be produced after the computations are completed.

If your sap calculations reveal that your property is not compliant, the Assessor will give you recommendations on improvements that may be made to make it so. It’s very important to liaise with your Assessor as early on in the project as possible because when the building is finished any non-compliances could possibly be quite costly to rectify.

If you need advice on a project you could have in , or require a quotation, give us a call or fill in our get a quotation form.


Here we have provided the most frequent queries asked about SAP Calculations in Hammersmith and Fulham.

So, Just What Are Sap Calculations

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

Sap Calculations, How Do They Cost

We would be pleased to offer discount rates, in particular for multiple dwellings which are the exact same or very similar construction. But typically for a single property the charge would be in the area of £120 – £300. By supplying the plans, you will be able to get a fixed quotation.

What Is The Difference Between Sap and EPC

Before we explain the difference, this is what you will need 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 computations of pre defined data set of a buildings design that’s put together to demonstrate the energy effectiveness of a dwelling. An EPC or Energy Performance Certificate is a overview report derived from the Sap calculations which produces a SAP score from 0 to 100. This score is expressed on the EPC as A the highest to G the lowest. It will also list suggestions that would improve the rating of your property.

There are actually 2 types of EPCs. First is a SAP EPC that is produced from building plans where all of the elements of the construction are known. This would normally be needed by building control to demonstrate that a property satisfies specified targets essential to the building regulations. Building control would must also see the SAP calculations which illustrates in detail whether all the components going into your property comply with the building regulations.

The second sort of EPC is the standard one that would be required for anyone who is marketing, or renting a property. This sort of EPC uses what’s called rdSAP, which is short for Reduced Data Standard Assessment Procedure, which is used where specific thermal values of, for example, the walls, roof, floors, etc, usually are not precisely known on an existing property. In this instance assumed thermal values are used according to the age of your property. This type of EPC would be no use to demonstrate compliance with any building regulations. Sometimes building control would simply ask you to get an EPC, but what they would really need are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is actually summary report of the Sap calculations).

If you are still confused, then give us a call to get more assistance.

What Are As Built SAP Calculations

These will be the finished set of SAP calculations generated after the building has been completed to hopefully demonstrate that it is compliant with Part L1A of the building regulations. Ahead of the construction starting, it should have had some “Design Sap” calculations to demonstrate that the proposed construction, in theory at least, would be compliant with Part L1A.



How To Do Sap Calculations

Unfortunately this is not something you could do yourself. The calculations must be carried out by an On Construction Domestic Energy Assessor or OCDEA, using approved Government computer software. The Assessor must be certified under one of several certification schemes and is also regularly audited to keep their certification.

What Info is Needed 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 property require Sap calculations to prove compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.


Sap Calculations For Extensions

It’s now modern to get large bi-folding doors, sky lights and large amounts of glazing on new extensions. However with the current building regulations the quantity of glazing can be no more than 25% of the floor area of the new extension. So over compensations in the thermal elements in other areas of the property will need to be made to demonstrate that the CO2 emissions coming from the existing house and the proposed extension is not any worse than the existing house and an extension where the glazing is within the allowed amount judged against Part L1B of the building regulations.

You need SAP calculations to find solutions and illustrate compliance.


Sap Calculations For Conversions

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


Will 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 list is not exhaustive. If you’re not certain whether you need them, then simply give us a call.


Our Services

What You Can Expect From Us

Trusted & Experienced

Our Assessors are fully qualified and accredited with years experience carrying Sap calculation in Hammersmith and Fulham . We also cover the whole of the UK and can assist on any project nationally.

Reliable & Fully Insured

You will be allocated 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 seek to provide 100% satisfaction and look forward to working with you.


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