Vapour seals (or not)?......

Following on from my other thread about downlight fittings I have a more general question which I hope someone can clear up for me. Reading around the place has got me a bit worried.... (a little bit of knowledge and all that...)

We had a large extension about 11-12 months ago (with planning permission, building regs, etc). I know this is not popular around here but we had fire-rated downlighters in the kitchen (single storey so with roof space above), bedroom and ensuite bathroom (loft a bove). All the work was done by a registered electrician (including quite a bit of rewiring of the main house, new CU etc) and we have a NAPIT certificate for all of it.

One thing that concerns me is reading around the internet I have read that in kitchens and bathrooms (or areas communicating with a loft space) there is a need for a 'vapour seal' around downlights to prevent condensation etc. I think products like the 'loft cap' are designed for this purpose.

Can someone clarify the regs regarding the use of these lights in these circumstances? As far as I am aware, I don't have any of these seals around the lights, and as I have outlined in my other post some of the lights don't fit snugly in the ceiling (although I am hoping to sort this out with adjustments....).

Should this have been done?
Should I be worried, given that all the work has been certified and registered?
How easy is it to seal these fittings? Does the foam around the light's fitting surface constitute a seal?

I'd be grateful for any advice. Thanks in advance.

The seal you have in your downlights is an intumescent seal designed to swell up in a fire and plug the downlight hole. This is different to a vapour seal. If you require a vapour seal because of building regs part L, then you can add a loftcap. Have you been asked to fit them?

It's Part C which requires a vapour seal - as long as the insulation is continuous and covering the lights then Part L has not been contravened.

NHBC downlight installation guidelines: http://www.nhbcbuilder.co.uk/NHBCpu...ical/StandardsExtra/filedownload,21353,en.pdf

Pre-formed cap to seal downlights: http://www.aico.co.uk/firecap_loftcap.htm (It's NOT a firehood....) And it needs to be sealed, not just plonked there, so I hope you have access to them from above...

Thanks for your replies. I've not been asked for a vapour seal, and as I say we've had our certificate of conformation with building regs etc. It was just when I was looking around for other information, I happened across THIS and got a bit concerned.

So does that mean that assuming the lights fit well and that the loft space above them is suitably insulated then no other vapour seal is required? If so then I assume this is the reason that the electician didn't install anything formal.

I guess what I need to know is whether a formal vapour seal should have been installed. Given the circumstances, would you install a formal vapour seal when fitting downlighters in the kitchen or bathroom? Could this vapour seal take the form of a silicone sealant around the light fitting?

So presumably I havent got anything too much to worry about? Or should I be chasing down the electrician?

FWIW I can access the loft above the bathroom easily enough, but not the roof space above the kitchen.

NB ban-all-sheds - that NHBC link appears to be broken...
Sorry for the clarification, but obviously I'm not in the trade!

gus4778 said:

Thanks for your replies. I've not been asked for a vapour seal, and as I say we've had our certificate of conformation with building regs etc.

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Sadly, many electricians (and this is one of the reasons for the widespread resentment of the whole Competent Person regime) never took on board the fact that their work has to comply with ALL of the Building Regulations, not just Part P.

If your guy signed a piece of paper to say that what he did complied with the Building Regulations, and he made holes into an unheated loft space and did not seal them then he misled you - he should not have signed it.

So does that mean that assuming the lights fit well and that the loft space above them is suitably insulated then no other vapour seal is required?

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No it doesn't - the insulation is what means you do need a vapour seal, as the insulation stops the loft space from getting warm, and therefore you'll get condensation up there.

If so then I assume this is the reason that the electician didn't install anything formal.

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I'm assuming ignorance.

I guess what I need to know is whether a formal vapour seal should have been installed.

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IMO yes - check with LABC.

Given the circumstances, would you install a formal vapour seal when fitting downlighters in the kitchen or bathroom?

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Yes.

Could this vapour seal take the form of a silicone sealant around the light fitting?

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Probably not, as the actual fitting is probably not internally air-tight.

So presumably I havent got anything too much to worry about?

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Or should I be chasing down the electrician?

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Check what LABC say - with no access from above then remedial work in the kitchen could be expensive. You should be on firm ground before going after the electrician. Even better if you can interest LABC in going after him.

NB ban-all-sheds - that NHBC link appears to be broken...

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Hmmm - try this one - it's a similar, or the same, article: http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,16553,en.pdf

The NHBC have required all downlighters to be sealed since July 2005: http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,25275,en.pdf

Sorry for the clarification, but obviously I'm not in the trade!

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That's alright - neither am I....

Thanks for that.

I'll probably give LABC a call... it seems from those links that NHBC has made it a requirement, but is this in excess of the standards for building regs? I guess the LABC will tell me this.

Do you think that the majority of electricians are using these seals in practice or that they 'should' be in an ideal world? I only ask because I know loads of people who have these downlighters in similar circumstances, and to the best of my (and their!) knowledge it is not something that has been done....

Because (most) electricians think that all they have to worry about are the electrical aspects...

Screwfix has half a dozen fire hoods, but no vapour hoods/seals. That's indicative of the requirement of part C being ignored.

Here's the advice in the Approved Document part C:

6.12 To avoid excessive moisture transfer to roof voids gaps and penetrations for pipes and electrical wiring should be filled and sealed; this is particularly important in areas of high humidity, eg bathrooms and kitchens. An effective draught seal should be provided to loft hatches to reduce inflow of warm air and moisture.

And here's the actual legal requirement:

C2 The walls, floors and roof of the building
shall adequately protect the building and people
who use the building from harmful effects
caused by—
(a) ground moisture;
(b) precipitation including wind-driven spray;
(c) interstitial and surface condensation;
and
(d) spillage of water from or associated with sanitary fittings or fixed appliances.