Home | About us | What we do | Sectors | Contact us | Careers | Travel to BRE | News & Information | Services A-Z | Login

Green Guide Calculator

Frequently Asked Questions:

This FAQ is available to download along with step by step instructions on how to use the Green Guide Calculator within our comprehensive Guidance Document.

  1. Where can I find the element number?
  2. The available element sub-categories do not sufficiently describe my specification. What should I do?
  3. Why has no rating been calculated for my specification?
  4. What type of insulation should I use?
  5. Thickness X is not sufficient for my specification; or additional materials are needed to complete a single layer.
  6. Can I model a Green/Brown roof using the Green Guide Calculator?
  7. Can I model a Basement or underground wall using the Green Guide Calculator?
  8. Can I model a roof light or atrium using the Green Guide Calculator?
  9. My Upper Floor specification requires insulation, but this is not available in the Green Guide Calculator.
  10. Why can I not specify a particular floor finish as part of a Ground, Upper or Separating Floor specification?
  11. What does "Aluminium curtain walling types 1, 2 & 3" mean?
  12. I am registered to perform Code for Sustainable Homes assessments via a thrid party organisation, but I am also registered with BRE for BREEAM so I can access the Green Guide Calculator. Can I use the Green Guide Calculator to model specifications required as part of an assessment registered through a third party?
  13. I need to submit a bespoke request to BRE for multiple specifications, which all have the same problem, or missing data. What should I do?

 

1. Where can I find the element number?

The element number, or reference is shown:

  • On the project homepage, where all of the elements created within a single project are listed.
  • On the printer-friendly report, in the specification box, under "ID".

[Top of the page]

 

2. The available element sub-categories do not sufficiently describe my specification. What should I do?

The categorisation of element specification sub-types is for information only. The calculations which compare the specifications and generate Ratings are performed on the category as a whole. E.g. External wall specifications are compared to all other external wall specifications to generate the rating, regardless of sub category.

Therefore the actual sub category chosen is not vital for the assessment; please choose whichever category is closest to the specification type you are attempting to model.

[Top of the page]

 

3. Why has no rating been calculated for my specification?

Please check that you have added layers to the specification, in addition to the descriptive text in the "Element Description" field.  Click the "Add Layer" button to find and add detail to the specification.  Please see section 1.7 in the guidance document.

[Top of the page]

 

4. What type of insulation should I choose?

For an Element Specification to comply with the regulations set out in the BREEAM/EcoHomes/Code for Sustainable Homes, a generic type of insulation must be assumed for the Mat1 credit. The components which contain this insulation material are marked with a “*” character at the end of the description.

Some specific constructions, e.g. a SIP panel with PIR insulation, or a manufacturer-specific product may be modelled as appropriate with the correct type of insulation.

The impacts of specific insulation types are taken into account in the section for the Mat6 credit.

The exception to this rule is where a Code for Sustainable Homes Level 5 or 6 is required.  In this instance, please choose the most appropriate insulation type from the options available.

[Top of the page]

 

5. Thickness X is not sufficient for my specification; or additional materials are needed to complete a single layer.

Assessors may use multiple instances of the same component, where an increase in material thickness is required.

Different components can be used in combination where a single component is not sufficient to fulfil the design requirements.  You may label multiple layers with the same “layer number” to show where items should be grouped.  The order of the layers does not affect the calculated rating, but are used to improve the logic of the model.

[Top of the page]

 

6. Can I model a Green/Brown Roof using the Green Guide Calculator?

Green/Brown Roofs are not assessed directly within the guide.  This is because the building assessment methods (BREEAM, EcoHomes and the Code) do not have any way currently of recognising the benefits of these types of roofs in terms of albedo effect, reduced run off, biodiversity, etc.  Thus within Green Guide they would only be penalised in terms of the additional materials (root barriers, growing media, sedum, etc.)

Therefore, for any green roof specification, we will ignore the additional materials required specifically for the green roof function and only model those materials which form the basic structure.

Alternatively, you may locate the generic roofing specification which most closely matches the construction required, but ignoring the green roof covering and support (i.e. substituting a generic tile roof or similar).

[Top of the page]

 

7. Can I model a Basement or underground wall using the Green Guide Calculator?

Basement walls are excluded from Mat1 assessment.  No Green Guide Specification is required.  Please mark this as “excluded” or “not assessed” within your report.

[Top of the page]

 

8. Can I model a roof light or atrium using the Green Guide Calculator?

If the roof light performs the same function as a window, then it can be assessed as a window; in which case an element-specific proforma is available to download from the BREEAM extranet, and must be submitted to us separately.

Areas such as atriums are a type of roof construction which does not comply to our standard functional unit. These are to be excluded from assessment. Therefore no Green Guide Rating is required.

[Top of the page]

 

9. My Upper Floor specification requires insulation, but this is not available in the Green Guide Calculator.

Usually we do not include insulation in a typical Upper Floor specification, unless it is a Separating Floor.  If you compare the functional unit descriptions for both Upper and Separating floors, this may help to define how it should be categorised.

If your specification should be a Separating Floor, then please recreate the element using this category and element type.  This may make a difference with regard to the Green Guide Rating calculated.

[Top of the page]

 

10. Why can I not specify a particular floor finish as part of a Ground, Upper or Separating Floor specification?

Floor finishes are assessed as a separate category within the Green Guide to Specification.  Floor finishes are therefore not included as part of the floor structure.  Please exclude this material layer from the model.

For a bespoke Floor Finish rating, please complete the Floor Finishes proforma available through the BREEAM Extranet, and submit to BRE.

[Top of the page]

 

11. What does “Aluminium curtain walling types 1, 2 & 3” mean?

The descriptions of some components have been condensed to fit as drop down list entries.  Please see below for the expanded descriptions of some of the more complex components:

“Curtain walling, aluminium type 1, frames, fixings.”
Aluminium curtain walling type 1 (3 transoms per floor) (includes mullions, transoms, clamping strips, cover plate and fixing brackets), Aluminium Mullion 121 x 50mm, Transom 121 x 50mm.

“Curtain walling, aluminium type 2, frames, fixings.”
Aluminium curtain walling type 2 (1 transom per floor) (includes mullions, transoms, clamping strips, cover plate and fixing brackets), Aluminium Mullion 184 x 50mm, Transom 184 x 50mm

“Curtain walling, aluminium type 3, frames, fixings.”
Aluminium curtain walling type 3 (2 transoms per floor) (includes mullions, transoms, clamping strips, cover plate and fixing brackets), Aluminium Mullion 142 x 50mm, Transom 142 x 50mm

[Top of the page]

 

12. I am registered to perform Code for Sustainable Homes assessments via a thrid party organisation, but I am also registered with BRE for BREEAM so I can access the Green Guide Calculator. Can I use the Green Guide Calculator to model specifications required as part of an assessment registered through a third party?

Unfortunately at this time BRE are unable to provide support to assessments registered through another company. Please refer to the guidance provided by the relevant scheme operator for the completion of bespoke ratings requests.

[Top of the page]

 

13. I need to submit a bespoke request to BRE for multiple specifications, which all have the same problem, or missing data. What should I do?

To allow us to respond quickly to your query, submit only ONE of the specifications to BRE. The response and guidance can then be applied to all specifications with the same issue.

[Top of the page]