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

We would be pleased to offer discounts, for example for multiple dwellings that are of the same or very similar construction. For individual dwellings then you would be looking in the region of £120 – £300 dependant upon the complexity of the design and the size. By providing the plans, it will be possible to get a fixed quotation.

Before we explain the difference, here is what you will require 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 computations of pre defined data set of a properties design that’s put together to demonstrate the energy efficiency of a dwelling. EPC is short for Energy Performance Certificate and it’s a summary report from the SAP calculations in an easy to understand 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 which is created from building plans where all the components of the building are known. This will normally be needed by building control to show that the property meets specific targets essential to the building regulations. Building control would also need to see the SAP calculations which shows in detail whether all of the components going into the property conform to the building regulations.

The second sort of EPC is the standard one that will be required if you are marketing, or renting a property. This particular EPC uses what’s called rdSAP, which is short for 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 existing property. In this situation assumed thermal values are used based on the age of the property. This particular EPC will be no good to show compliance with any building regulations. Sometimes building control would simply ask you for the EPC, however what they would really require are the Sap calculations (which is the information behind the EPC) and the SAP EPC (which is actually summary report from the Sap calculations).

If you are still perplexed, after that phone us for additional assistance.

These will be the finished set of SAP calculations created after the dwelling has actually 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 a set of “Design Sap” calculations to show that the planned construction, in theory at least, will be compliant with Part L1A.

Unfortunately this is not some thing that you can do yourself. Sap calculations need to be done by an On Construction Domestic Energy Assessor or OCDEA, using approved Government software. The Assessor must be approved under one of the certification schemes and is also regularly audited to keep 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)

Every new property require Sap calculations to demonstrate compliance with Part L1A (Conservation of fuel and power in new dwellings) of the building regs.

It’s now popular to have large bi-folding doors, sky lights and large quantities of glazing on new extensions. But with the current building regulations the amount of glazing can be no more than 25% of the floor area of the new extension. So over compensations on the thermal elements in other parts of the property will have to be made to demonstrate that the CO2 emissions from the existing house along with the planned extension is not any worse when compared to the existing house and an extension whose 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.

For anyone who is altering the use of a dwelling, you will need 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 list is not exhaustive. Contact us, if you are unsure if you require them.