Spot lights on a flat roof - fire!!!!!

[hilali]

I wonder if anyone can hlep because I am running in circles because of this.
My electrician and builder dont want to put spot lights in a flat roofed room due to risk of fire. My my readings tell me LED lights are safe and if one wants to be doubly sure can put a "hood" over the light. I am aware of cutting a hole in the insulation but that again something the builder didnt want to do. I wonder what you suggest?

 

[Deleted member 9648]

Could be they dont want the hassle of trying to get downlights in celotex....a nightmare,but do-able,think they are bull-pooing you with the 'fire risk' line

 

[Baker1988]

Aslong as nothing is layed over the top 'ie insulation' and there is suitable airflow for the heat to disburse then I don't see any problem at all sounds like they just don't want to put them in

 

[Gethyn Turnbull]

Use fire rated downlighters, when they are putting in the celotex ask them to leave a clear gap for a sufficient airflow. If you are still paranoid use LED lamps which gives out hardly any heat. You probably could even use fire hoods aswell as firerated spots ..........:smilielol5:

 

[telectrix]

risk of fire is only there if they can't be arsed to fit them properly. are they going to refuse to connect up the boiler in case it catches fire?

 

[Dave 85]

They're talking ****

 

[Baker1988]

risk of fire is only there if they can't be arsed to fit them properly. are they going to refuse to connect up the boiler in case it catches fire?

I agree aslong as you fit correctly and not bodge it up they will be fine they wouldn't be able to sell them if they wasn't safe

 

[Jamie444]

What is it with builders and kingspan and celotex? You ask them to leave a space for your downlights and when you come to cut your holes they filled the gap with insulation. Makes my blood boil!!!
They are more likely trying to put you off the idea.As long as you have sufficient clearance in accordance with the downlights spec and there is airflow at the back of the fitting you should have no problem.perator:

 

[Gavin A]

I reckon people are being a bit quick to judge here without knowing all the facts.

There are other considerations here as well as safety, such as minimum U values for the roof that could well be pretty hard to meet if you're going to be cutting holes through the insulation all over the roof - bearing in mind that these holes will probably go all the way to the cold side of the insulation, this is one hell of a lot of cold bridging, particularly if using the enclosed downlighters, which will basically mean you've got a fair amount of metal running directly from the warm inside of the house through the metal enclosure to the cold side of the insulation.

If the U value calc is being done correctly then they'd have to take into account of maybe 1m2 or more of totally uninsulated ceiling, and maybe 0.1-0.2m2 of metal, within their overall calculations, which could well need an extra 50% thickness of insulation to compensate.

Even then, you'd potentially have problems with condensation and damp on the cold spots, though I guess this could be less bad because the spots will also be leaking cold air into the room so will keep that area ventilated.

Bottom line, putting led spots into an insulated flat roof contruction can be done safely, but it's still going to be a very bad idea in energy efficiency terms that you'll be paying for in your energy bills for the rest of the time you live there, and will either mean your roof isn't building regs compliant, or it will cost you quite a lot extra in the insulation to compensate for the heat losses from the uninsulated sections of ceiling.

 

[Gavin A]

What is it with builders and kingspan and celotex? You ask them to leave a space for your downlights and when you come to cut your holes they filled the gap with insulation. Makes my blood boil!!!
They are more likely trying to put you off the idea.As long as you have sufficient clearance in accordance with the downlights spec and there is airflow at the back of the fitting you should have no problem.perator:

It's probably because you're making their roof non-compliant with the minimum U value requirements needed for building regs compliance. Or do you carry out U value calcs in advance of cutting holes in the insulation to ensure it's still compliant?

 

[Jamie444]

It's probably because you're making their roof non-compliant with the minimum U value requirements needed for building regs compliance. Or do you carry out U value calcs in advance of cutting holes in the insulation to ensure it's still compliant?

I was referring to the original post which quoted the builder and electrician didn't want to fit the spotlights due to being a fire hazard, not because of the u values.
If the builder has done his u value calculations and says no downlights for that reason then you can't argue with that and you would have to go with another type of lighting alternative.

 

[Gavin A]

I was referring to the original post which quoted the builder and electrician didn't want to fit the spotlights due to being a fire hazard, not because of the u values.
If the builder has done his u value calculations and says no downlights for that reason then you can't argue with that and you would have to go with another type of lighting alternative.

true, but without wanting to dis the thread starter, how many customers have you known that always get the full picture prior to taking to the internet to try to prove you wrong?

I'm just saying that there could well be more to the builder and sparks reasoning than is apparent from the OP. Fire risk could be because they can't comply with building regs on energy efficiency without covering any hole with insulation, so they either install a roof that doesn't comply with building regs for insulation, or they install it in a way that creates a potential fire risk, or they advise the customer that it can't be done.

Out of interest, I'm just working up a U value calc for this to see how much extra insulation would be required to compensate.

 

[Jamie444]

true, but without wanting to dis the thread starter, how many customers have you known that always get the full picture prior to taking to the internet to try to prove you wrong?

I'm just saying that there could well be more to the builder and sparks reasoning than is apparent from the OP. Fire risk could be because they can't comply with building regs on energy efficiency without covering any hole with insulation, so they either install a roof that doesn't comply with building regs for insulation, or they install it in a way that creates a potential fire risk, or they advise the customer that it can't be done.

Out of interest, I'm just working up a U value calc for this to see how much extra insulation would be required to compensate.

I suspect your right. The builder doesn't want the u value altering due to spaces in his insulation.in that case he should be clear on the reason to the customer and then there is no argument.i would think also the cost and extra work involved in adding insulation due to the downlights being installed would not be included in his original quotation!!!

 

[Gavin A]

I suspect your right. The builder doesn't want the u value altering due to spaces in his insulation.in that case he should be clear on the reason to the customer and then there is no argument.i would think also the cost and extra work involved in adding insulation due to the downlights being installed would not be included in his original quotation!!!

not just that, but the thickness of the rafters, height of the roof etc is probably determined by the thickness of the insulation, so unless this is being done at planning stage, chances are that it's far too late to be considering this sort of a change without serious cost implications.

 

[Jonny66]

IMO how can you so readily come to a conclusion that the builder and electrician are talking rubbish..........they are on site and have seen the flat roof, you are basing your opinion on what? your imagination and a vague description from the client (who isnt competent and needs to employ perhaps a builder or electrician to have a look?) .....and so the never ending cycle of madness goes on.....I know whose opinion I would take, but that's clients for you.......pay for professional help get them to have a look, disregard everything they say and seek opinions from a forum and people who have no idea what the REAL situation is because they are not there..........humans aren't they great

 

[Jamie444]

I am guessing here but sounds like to me the flat roof is built and the insulation is to be installed next after the wiring for whichever lighting (to be decide) is 1st fixed.

 

[Jonny66]

I am guessing here but sounds like to me the flat roof is built and the insulation is to be installed next after the wiring for whichever lighting (to be decide) is 1st fixed.

Thats the problem with these type of posts.......... so the answers the client so desperately wants to hear shouldn't be so easily given because they are just guesses..............

 

[Jamie444]

Thats the problem with these type of posts.......... so the answers the client so desperately wants to hear shouldn't be so easily given because they are just guesses..............

But also after reading these posts the client can take the information posted apply it to his situation then put the information to his builder/electrician. And between them come to an agreement.

 

[Jonny66]

But also after reading these posts the client can take the information posted apply it to his situation then put the information to his builder/electrician. And between them come to an agreement.

Cool, so next time your at your place of work and give your professional opinion, dont forget to inform the client to also ask some complete stranger (who's never seen the job) for their opinion....... so that between them and you, the client can come to some conclusion.........great train of thought there mate.

 

[Jamie444]

Yep.the facts are there.either the downlights are a fire hazard because the insulation is already installed and the client is trying to have them installed. Or the insulation isn't installed yet and fitting downlights will change the u value of the insulation. Either way the client and builder/electrician have to come to some agreement so the install is done correctly.