SAP Calculations
Planning Permission
Warm Roof sun lounge

SAP Calculations FAQ’s

1. What is an SAP Calculation?

SAP stands for “Standard Assessment Procedure”, the Governments approved procedure for energy rating domestic dwellings. Properties are given a rating score between 1 to 100 depending on their performance.

2. Do I need to have a SAP calculation, how much does it cost?

All extensions and sun lounges must have a SAP Calculation. Each calculation costs £195 + VAT.

3. How does ASW calculate the energy rating?

This is done by calculating the Target Carbon Dioxide Emission Rate (TER) for your property by using the Standard Assessment Procedure. Once this has been done, the Design Carbon Dioxide Emission Rate (DER) can be calculated by entering the actual design specification. To meet the requirements of the Building Regulations, the DER must be lower than the TER.

4. What happens if my proposed sun lounge fails to meet Building Regulations requirements?

We will advise you of the failure, and discuss suitable recommendations to improve the design to pass Building Regulations.

5. When should I have the assessment done?

You must have the assessment carried out before any construction work commences in case.


Planning Permission FAQ’s

You will need planning permission if one or more of the following statements applies to you:

1. Your sun lounge is forward of the front elevation or side elevation of the house and is facing a highway.

2. Your sun lounge and other buildings (including previous extensions) exceed 50% of the total area of land  around the original house**.

3. Materials used in the sun lounge are not similar in appearance to those of the exterior of the existing house.

4. The width of your sun lounge to the side of your house is greater than half the width of the original house.

5. Your sun lounge to the side of your house is taller than four metres.

6. Your sun lounge is within two metres of a boundary and the eaves is higher than three metres.

7. Your sun lounge extends beyond the rear of the original house by more than three metres if an attached house or by four metres if a detached house.

8. Your rear sun lounge exceeds four metres in height.

9. Your sun lounge eaves and ridge height are higher than those on the existing house.

10. If your sun lounge is on designated land* cladding to any part of the exterior of a sun lounge with stone, artificial stone, pebble dash, render, timber, plastic or tiles will need planning permission.

11. On “designated land”, side extensions will need planning permission.


* Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

** Original house means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Sheds and other outbuildings must be included when calculating the above 50% limit.


Warm Roof sun lounge FAQ’s

1. Do I need Building Regulations Approval for a sun lounge?

Unless your sun lounge is used as an entrance porch YOU WILL NEED BUILDING REGULATIONS APPROVAL.

2. How do I obtain Building Regulations Approval?

The best way to obtain approval is through ASW (in conjunction with our affiliated partners Assent Building Control). Simply fill in the forms and we will do the rest. This should cost no more than using your local authority and approval can be gained up to 7 weeks earlier when compared to other routes.

3.   Exactly what information do ASW need to comply with Building Regulations?

As well as filling in the forms and sending them to ASW, you will also need a location plan of your plot and a SAP Calculation (energy rating for your property / extension), these are required by law for your extension approval. These services are offered at ASW at very competative rates making the whole process much easier for you. Procedures for making Building Regulations applications are detailed by ASW, time savings also applying to Assent, and with additional national coverage site surveyors with established experience will be available to view ongoing works and report on site progress.

4.    With a standard sun lounge , what are the maximum dimensions depending on style?

Edwardian – at 600mm c/c – width 5.00 meters, projection 5.00 meters

Victorian – at 600mm c/c – width 6.00 meters, projection 5.20 meters

Lean-to – at 600mm c/c – width (unlimited), projection up to 3.0 meters

Duo pitch – at 600mm c/c – width 4.00 meters, projection up to 3.10 meters

5.    Can I fit the Warm roof to my existing conservatory?

If your existing support frames are reinforced and the conservatory is in good condition there should be no reason why a new sun lounge roof cannot be fitted to your old conservatory. Your existing foundations should be adequate to support the roof (as the Warm roof system is designed to be no heavier than a glass roof). If you have any concerns it may be prudent to expose a section of foundation for inspection by ASW prior to starting construction.