This is quite possibly the most frequent query asked. Check out Andrea’s video explanation above, or read the full explanation here on the right.

This might differ considerably dependant upon the size and complication of the dwelling, but a typical cost range will be between £120 – £300. There may be an additional fee of approximately £50 if an EPC is called for at the end of the build. For multiple dwellings of similar designs, then discounts could well be available.

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

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 demonstrate the energy effectiveness of a property. EPC means Energy Performance Certificate and it’s a summary report of the SAP calculations in an simple to comprehend document, which could also be used to market or rent out a property.

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

The 2nd sort of EPC is the regular one that will be required for anybody who is selling, or renting out a property. This type of EPC uses what’s called rdSAP, which means Reduced Data Standard Assessment Procedure, which is used where specified thermal values of, such as, the walls, roof, floors, etc, usually are not precisely known on an established property. In this situation assumed thermal values are used according to the age of the property. This kind of EPC will be no use to demonstrate compliance with any building regulations. Sometimes building control would simply ask you for an EPC, but what they would really need to have are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is a summary report of the Sap calculations).

If you are still perplexed, after that give us a call for further advice.

These will be the finished set of SAP calculations created once the building has been completed to confirm that it is compliant with Part L1A of the building regulations. Prior to the construction starting, it ought to have had a set of “Design Sap” calculations to demonstrate that the planned building, in theory at least, will be compliant with Part L1A.

No, this is not something you can do yourself. Sap calculations need to be done by an On Construction Domestic Energy Assessor or OCDEA, by using approved Government computer software. The Assessor must be approved under one of the accreditation schemes and is regularly audited to keep up their qualification.

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)

All new property need to have Sap calculations to show compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regulations.

It’s now quite fashionable to get large bi-folding doors, sky lights and large quantities of glazing on new extensions. However under the latest building regulations the amount of glazing must be a maximum of 25percent of the floor area of the new extension. So over compensations in the thermal elements in other places within the property will have to be made to show the CO2 emissions from the current house and the planned extension is no worse when compared to the existing house and an extension where the glazing is within the allowed amount judged against Part L1B of the building regulations.

You should have SAP calculations to find solutions and demonstrate compliance.

When you are modifying the use of a building, you will require Sap calculations. {The new dwelling will have to comply with Part L1B of the building regulations.}

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 is not an exhaustive checklist. If you’re uncertain whether you require them, then simply phone us.