I received the following information from the GGF and thought it may be of interest to those installing conservatories:
Within Approved Document L; there is no longer a definition for a conservatory; instead a dictionary definition is to be used:
Oxford Dictionary definition – a room with a glass roof and walls, attached to a house at one side and used as a sun lounge or for growing delicate plants.
Chambers Dictionary definition – a a greenhouse for plants; b a similar room used as a lounge, which is attached to and entered from, the house.
Cambridge Dictionary definition – a glass room, usually connected to a house, in which plants are grown and kept.
L1B 2010 edition states:
Conservatories and porches
3.15 Regulation 9 of the building regulations exempts some conservatory and porch extensions from the energy efficiency requirements. The exemption applies only for conservatories and porches:
• which are at ground level
• where the floor area is less than 30m2
• where the existing walls, doors and windows in the part of the dwelling which separates the conservatory are retained or, if removed, replaced by walls, windows and doors which meet the energy efficiency requirements; and
• where the heating system of the dwelling is not extended into the conservatory or porch
3.16 Where any conservatory or porch does not meet all the requirements in the previous paragraph, it is not exempt and must comply with the relevant energy efficiency requirements (see paragraphs 4.8 and 4.9 below).
Conservatory which are exempt from the energy efficiency requirements of AD L1B must comply with the requirements of building regulations Part N Glazing – safety in relation to impact, opening and cleaning and Part P Electrical safety – dwellings.
If a conservatory or porch is not exempt from the energy efficiency requirements because the 4 requirements stated above are not met then AD L1B refers to paragraphs 4.8 ad 4.9. These state:
Conservatories and porches
4.8 Where the extension is a conservatory or porch that is not exempt from the energy efficiency requirements (see paragraphs 3.15 and 3.16 above) then reasonable provision would be to provide:
a. Effective thermal separation between the heated area in the existing dwelling, i.e. the walls, doors, and windows between the dwelling and the extension, should be insulated and draught proofed to at least the same extent as in the dwelling.
b. Independent temperature and on/off controls to any heating system installed within the extension. Any fixed building service installed within the extension should also conform to the standards set out in paragraphs 4.24 to 4.37.
c. Glazed elements should meet the standards set out in Table 1 and opaque elements should meet the standards set out in Table 2. However the limitations on the total area of windows, roof windows and doors as set out at paragraph 2 above do not apply.
4.9 Removing and not replacing any or all of the thermal separation between the dwelling and an existing exempt extension, or extending the dwelling’s heating system into the extension, means the extension ceases to be exempt (see paragraphs 3.15 and 3.16 above). This constitutes a change in the building’s energy status (Regulation 4B). In such situations, the extension should be treated as a conventional extension and reasonable provision would be to demonstrate that the extension meets the guidance set out in paragraphs 4.1 to 4.7 above.
The effects of this guidance are:
1. For a conservatory to be exempt, all 4 requirements must be met in full.
2. If an extension is to be classified as a conservatory, it must be thermally separated from the dwelling, paragraph 4.8.a states that effective thermal separation must be installed.
3. If the extension is to be classed as a conservatory, the dwellings heating system must not be extended into it and any heating system installed in the conservatory must have independent temperature and on/off controls to the dwelling.
4. The regulations do not state that heating appliances such as radiators need to be fitted to fail the exemption criteria but states the dwelling heating system is not extended into the conservatory. For example, the installation of pipework from the dwelling’s existing heating system into the conservatory and for the homeowner to fit radiators at a later date, constitutes the dwellings heating system being extended and therefore the conservatory would not be considered exempt. This would appear to be the point of paragraph 4.9.
5. The final part (c) of 4.8 indicates that should the conservatory fail for reasons of being above or extending above ground level or being over 30m2, the conservatory glazing element must comply with the standards set out in Table 1 and Table 2 – Windows, roof windows or rooflights WER band C or better or U-value 1.6 W/m2 K.
6. If either the thermal separation or extension of dwelling heating system criteria cannot be met, the regulations are effectively stating that the extension cannot be classified as a conservatory but would be an extension that would be subject to 4.1 to 4.7. This would limit the total glazed area to the sum of 25% of the extension floor area plus the total area of any windows or doors which as a result of the extension works, no longer exist and are no longer exposed, or use the area-weighted U-value method, or whole dwelling calculation method.
Tags: Approved Document L, Conservatories, Conservatories Building Regulations 2010, definition of conservatory, GGF
I feel confused by the above Mathew.
Anyway, I tend to sell conservatories with full building regs so I guess/hope the impact, if any will be less for me. I’m never sure why all the companies seem to shy away from b/regs. Must be a cost thing.
Ron