Conservatory building regs

I'm having a bit of a problem with the design of our new utility room/conservatory and the building regs. people and was wondering if anyone has any ideas.
We got the builders to extend the house up to the old garage and was planning to convert the garage into a conservatory/utility room. The design I was going to go for has the right and far walls with solid brick for 1/3 at the bottom and 2/3 toughened glass above. I was going to leave the left wall as it is because it's on the boundary of the property and the neighbours garage is about 40cm on the other side. Roofing was going to be just clear square walled plastic sheets.
It turns out that although conservatories don't need to be inspected the building has to have over 50% transparent external walls to count as a conservatory. If it doesn't meet that requirement then it appears that it has to be built with double skin walls, double glazing etc.
http://www.cambridge.gov.uk/planning/formsgns/conservatories.pdf
The snag is that the building inspector says the design will have less then 50% glass because of that solid brick wall and the brick bases to the windows! Aargh! The crazy thing is that the building will be unheated and will only have a plastic roof so a double skin and double glazing would be a complete waste of time and money as far as I can tell.
I could put windows along the wall facing my neighbours garage but that would look ugly and I suspect I might run foul of planning regs for putting windows which look onto the neighbours property (even if all the window faces is a brick wall). The only other thing I can think of is to bring the glass all the way down to near the floor but I don't particularly want to do that as I don't think it would look as good.
I've no idea what the regulations are trying to achieve, they seem pretty crazy to me as the room is unheated and is outside the main house walls etc. so there will be no heat loss through it. I was wondering if anyone has any experience of this, or any ideas how to meet the regs without dramatically changing the design?
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I'd go that method. Full height glazed conservatories can look very good, especially if rather than using large glazed panels that make it look like a shop, you just replace a wooden panel with a small glazed unit or two. Companies such as Baltic Pine would be delighted to supply you with wooden frames and glazed panels in this configuration. They look particularly handsome with glazed fanlights with a single Georgian bar such as the following diagram, with all panels glazed. Personally, I think dwarf wall conservatories look a bit odd and prefer full height designs, whether the bottom panels are glazed or wood panelled.
+--+--+ | | | +--+--+ | | | | | | | | +--+--+ | | | | | | | | | +--+--+

The problem is that there is no way of preventing you plugging in a fan heater and making it heated.
I'd use double glazing anyway. It isn't that much more money and will make the room much more comfortable, particularly due to the large glazed area. Also, consider using triple wall polycarbonate (or better still, double glazed roof) for the same reason.
The building regulations don't require you to use cavity wall methods. Just bolting on sufficient thickness of Celotex insulation is enough and is recommended anyway. However, due to the large glazing requirement, you are unlikely to be able to comply with building regulations without using the conservatory exemption.
Christian.
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Many thanks for the advice.
Must admit I hadn't thought of putting in panelled glass rather than just single sheets. It was the shop window look I was trying to avoid.
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On Fri, 20 Aug 2004 09:15:49 GMT, Sapient Fridge

One way is to build inside the regs, then alter it with a minor uninspected alteration later.
Rick
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On Fri, 20 Aug 2004 09:15:49 GMT, Sapient Fridge

Someone I know had a similar situation - they built it with windows facing the neighbour to meet the regulations and then put up "shutters" (rather nice faced boards) over the windows inside and out immediately afterwards. They had told the neighbour what they intended to do beforehand so there were no complaints about overlooking them.
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On Fri, 20 Aug 2004 09:15:49 GMT, a particular chimpanzee named
keyboard and produced:

If it is unheated, and you're not making the existing external walls or doors between the heated part of our house and this extension any worse (or if you're installing any doors, that they are external quality and draught-stripped), then there is no limitation on the heat loss through the extension; as per Approved Document L1, Sections 1.59 to 1.61.
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The problem is that 1.58 says:
> 1.58 For the purposes of the guidance in Part L, a conservatory has not > less than three-quarters of the area of its roof and not less than one half > of the area of its external walls made of translucent material.
It's that second bit that is causing the problem, if I have less than half glass then it no longer counts as a conservatory.
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On Sat, 21 Aug 2004 07:42:40 GMT, a particular chimpanzee named
keyboard and produced:

Conservatories are exempt from the Building Regulations if they meet the criteria in Schedule 2 of the 'Regs, which is: "the extension of a building by the addition at ground level of... a conservatory...where the floor area of that extension does not exceed 30m, provided that in the case of a conservatory or porch which is wholly or partly glazed, the glazing satisfies the requirements of Part N of Schedule 1".
The problem comes in that there is no adequate definition of a conservatory. IIRC, the old 'Manual to the Building Regulations' gave it as having a transparent or translucent roof, with no mention of the glazing to the walls. The guidance in AD L1 only relates to conservatories to which the Regulations apply; namely those which are constructed at he same time as the house, or those which don't meet the other exemption criteria. It's circular logic to apply this as a criteria as to whether the conservatory is exempt. Unfortunately, this logic has been adopted by many authorities and/or officers.
There's two separate routes to compliance here; 1. Your proposed extension is an exempt conservatory, in which case, it doesn't matter how you construct it; or 2. It's an unheated extension, in which case a Building Regulations application is required, and matters such as its structure, fire safety, drainage, etc will need to satisfy the Requirements. With your extension also containing a utility room, I would suggest that it falls into the second route.
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The rules are there to stop people building what are in fact extensions to their living space, e.g. utility rooms, disguised as "conservatories". Around here its very tempting for people to want to convert their integral garages to e.g utility room + kids play room, but a lot of work has to be done to get through the regs,or if they ignore then problems when they sell.
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