Downlighters in celotex

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Hi

I am contemplating installing some standard downlighters in a vaulted ceiling (subject to a previous question i have just posted).

The ceiling has 150mm of celotex installed between and underneath a sloping ceiling.

Do I have to cut great swathes of insulation out around each of the downlighters?

Seems as though i could end up with large cold spots around the lights.

Does anyone know of any 'cold' downlight solutions? I did wonder about led downlights, but only like the 'warm' style bulbs which are like £30 each

Thanks in advance.
 
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You cannot fit downlighters in the the celotex, as they will overheat and set on fire.
You cannot cut holes in the celotex either, as vast amounts of heat will be lost and it won't comply with building regulations.

The answer - fit some other style of lighting.
 
As above or create a false ceiling and pepper it with as many downlights as you want, at 50W each, 1 per linear metre and a meter apart would suffice.
 
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Hi

I am contemplating installing some standard downlighters in a vaulted ceiling (subject to a previous question i have just posted).

The ceiling has 150mm of celotex installed between and underneath a sloping ceiling.

If this is new space and has building control involved then you must confirm with BC what they will accept.
The thermal requirements in roofing is very specific - you cannot go hacking holes in the celotex. If you do BC will tell you to put it back.
 
Hi

I am contemplating installing some standard downlighters in a vaulted ceiling (subject to a previous question i have just posted).

The ceiling has 150mm of celotex installed between and underneath a sloping ceiling.

If this is new space and has building control involved then you must confirm with BC what they will accept.
The thermal requirements in roofing is very specific - you cannot go hacking holes in the celotex. If you do BC will tell you to put it back.

The U value figures for ceilings/walls etc are AVERAGE values. as long as they are airtight (draught proof), and you seek guidance from building control, it shouldnt be a problem. You may have to increase the insulation thickness to the next one up. If you had your plans in prior to Oct 2010, you should be able to use the pre oct 2010 figures.

Ignore comments on here; the I think recent events show that "global warming" is a complete and utter myth. Within 20 years, the UK will pretty much be supplied by nuclear anyhow. We installed 11 50W downlights in our living room (7.5m X 4 m) and it looks awesome, much better than HF lighting, far smaller holes and the gear is far more tolerant to local dodgy electricity supplies.

you cannot go hacking holes in the celotex. If you do BC will tell you to put it back.

You can, as long as the average U value across the building meets the requirements.

If you have a right lefty sandal-wearing BCO, get BC to sign off the construction then get the downlights installed afterwards.

My only concern would be if the celotex is acting as a vapour barrier, in which case any holes could allow damp air into the gap which is supposed to be airtight. Result will be damp, which isnt good for wiring or wooden joists.
 
If local BC get unionist on you, you can quote the below reference:

http://www.bre.co.uk/filelibrary/pdf/rpts/BR_443_(2006_Edition).pdf
Recessed light fittings
For recessed light fittings in an insulated ceiling where the insulation in the
vicinity of the light fitting has been removed to allow the dissipation of heat,
either obtain the overall U-value of the roof as an area-weighted average or
add a correction, ΔU, to the U-value of the roof according to:
ΔU = f (2.0 – Uroof)
where f is the fraction of the total ceiling area with removed insulation and
Uroof is the U-value of the roof before application of the correction.
 
Must get some new batteries for my slide rule.

If you can argue that point then they will next hit you with the passage of moisture curved ball.

It is much easier not to install the nasty things in the first place.
 
Must get some new batteries for my slide rule.

If you can argue that point then they will next hit you with the passage of moisture curved ball.

It is much easier not to install the nasty things in the first place.

As long as the recessed lighting is airtight (heatproof caulking/seal) then I dont know how they could.

Building control - nothing but a load of jobsworths.
 
I think recent events show that "global warming" is a complete and utter myth.
That statement displays such ignorance and contrariness that "I think" is a lie - you are incapable of thinking.

Mate, you are speaking to someone who burns 7 tonnes of Kerosene an hour; there is absoulutely no evidence whatsoever that global warming is man-made.

If you think that turning down the boiler or choosing PELs over halogen is going to make the slightest bit of difference, you need to consider the complete carbon cost; something that environmentalists seem to forget.

For example, corn based fuel consumes more in oil based fertiliser than it produces

Wind turbines in the channel will require 10 years of generation before they pay off for the carbon cost to construct them

PV panels will NEVER regenerate the energy used in their manufacture.

The only reason we have governments worried about consumption is down to peak supply. Nothing to do with "global warming". They are worried the lights will go out when global supply cant keep up with demand. What is there to suggest that global warming in fact isnt down to natural phenomenon? Do you know what the global contribution to the environment in terms of SO2 and CO2 is from volcanic eruptions as opposed to man made?

That doesnt mean I dont try and save energy, either at work, where the scale of being careful can lead to tonnes of fuel saved, or at home, by installing insulation and getting a more efficient boiler.

But I would be lying if I said I was doing it for environmental reasons and I certainly am not going to have my concience tweaked over picking 550W and nice tidy small downlighters over industrial sized and electrically sensitive High frequency lighting.
 
there is absoulutely no evidence whatsoever that global warming is man-made.
Absolutely none, eh?

I wonder why, in that case, the IPCC have stated that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely (>90%) due to the observed increase in anthropogenic (human) greenhouse gas concentrations?

And that the probability that this is caused by natural climatic processes alone is less than 5%?

I wonder why over 30 national science academies have issued joint declarations confirming man-made global warming, and urging countries to reduce emissions of greenhouse gases?

I wonder why hundreds of countries have signed the Kyoto protocol?

I wonder why survey after survey of published papers and of direct polling of scientists shows that an overwhelming majority agree that man-made climate change is real?

We are talking here of the work involving thousands of scientists, all peer-reviewed. We are talking here of organisations like the Royal Society saying ""There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation." Of the American Association for the Advancement of Science saying "The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society."

I wonder why surveys have formed conclusions such as

"the relative climate expertise and scientific prominence of the researchers unconvinced of ACC (Anthropogenic Climate Change) are substantially below that of the convinced researchers."

and

"It seems that the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes."

?

I wonder why not one scientific body of national or international standing now rejects the findings of human-induced effects on global warming?


Do you really think that all this is some fantastically, (and historically utterly unprecedentedly well) organised conspiracy by hundreds of countries and thousands of scientists to scare us all into using less oil before it runs out?

Does every individual scientist agree? No.

Is 100% of the evidence unequivocal and consistent? No.

Is every single scientific paper correct? No.

But "absolutely no evidence whatsoever that global warming is man-made"? Please don't insult our intelligence.
 
there is absoulutely no evidence whatsoever that global warming is man-made.
Absolutely none, eh?

I wonder why, in that case, the IPCC have stated that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely (>90%) due to the observed increase in anthropogenic (human) greenhouse gas concentrations?

And that the probability that this is caused by natural climatic processes alone is less than 5%?

I wonder why over 30 national science academies have issued joint declarations confirming man-made global warming, and urging countries to reduce emissions of greenhouse gases?

I wonder why hundreds of countries have signed the Kyoto protocol?

I wonder why survey after survey of published papers and of direct polling of scientists shows that an overwhelming majority agree that man-made climate change is real?

We are talking here of the work involving thousands of scientists, all peer-reviewed. We are talking here of organisations like the Royal Society saying ""There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation." Of the American Association for the Advancement of Science saying "The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society."

I wonder why surveys have formed conclusions such as

"the relative climate expertise and scientific prominence of the researchers unconvinced of ACC (Anthropogenic Climate Change) are substantially below that of the convinced researchers."

and

"It seems that the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes."

?

I wonder why not one scientific body of national or international standing now rejects the findings of human-induced effects on global warming?


Do you really think that all this is some fantastically, (and historically utterly unprecedentedly well) organised conspiracy by hundreds of countries and thousands of scientists to scare us all into using less oil before it runs out?

Does every individual scientist agree? No.

Is 100% of the evidence unequivocal and consistent? No.

Is every single scientific paper correct? No.

But "absolutely no evidence whatsoever that global warming is man-made"? Please don't insult our intelligence.

If you think using PL instead of spots will make the slightest bit of differnce then I am sorry but you are wrong. More energy could be saved through opting for more efficient ways of heating their home. couple of hundred watts over say 100 to light a room? Your rads spit out 1Kw, thats per room! I bet in some greenies eyes, having a few PLs makes up for the fact they have no cavity wall insulation.

The reasons for cutting back on energy usage I disagree with, but the sentiment is the same, I agree we need to cut back. But being a green extremist over "wasteful" sic. lighting is nothing but P*ssing in the wind whilst I spit out 25 tonnes of CO2 per hour out the back of my Jet.
 
If you think using PL instead of spots will make the slightest bit of differnce then I am sorry but you are wrong.
My objection to the use of spotlights for room lighting is the engineering obscenity of the gross misuse of inappropriate technology. They are wrong wrong WRONG even if they only have a few W of LEDs in them.


But being a green extremist over "wasteful" sic. lighting is nothing but P*ssing in the wind whilst I spit out 25 tonnes of CO2 per hour out the back of my Jet.
Stop doing that then ;)

But I'm not being a "green extremist" - I don't agree with the idea of trying to light rooms using products designed to specifically not do what you're trying to use them to do.

I also agree that solar PV in these latitudes is a dangerous fantasy, made worse by the fact that we're going to kill more old people by bribing people into using it and that biofuels are environmentally negative.

Can we now return to the issue of there being absolutely no evidence whatsoever that global warming is man-made?
 
Can we now return to the issue of there being absolutely no evidence whatsoever that global warming is man-made?


Something that has always worried me about global warming, is that the climate has been warmer than now in the past. For example in the early middle ages the climate in Greenland was warm enough to allow the Vikings to live by northern european subsistance agriculture, until they were wiped out when temperatures fell in the little ice age. Also the moors of Devon and Cornwall were farmland in the Bronze Age, when the climate was also warmer than now.

So who was burning all the fossil fuel in the Bronze Age, and the Dark Ages after the fall of the Roman Empire? I don't say that there is no such thing as global warming, and it may be caused by human emitted CO2. But as we are still well within the natural range of temperatures, why is it such a disaster? When I was at school we were being taught that we were over due for an Ice Age, now it is Global Warming. I can not help suspecting that in a few more years Global Warming will also be history.
 

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