Downlights with no roof space

[Deanspoors]

I'm in the process of building an extension, it's all built and weatherproof with only the internals to complete. I am having a head scratching moment with the downlights though. The roof is a vaulted ceiling type, I have to fit 140mm of insulation, which I believe will be 50mm air gap and then 100mm insulation between joists, followed by another 40/50mm of insulation board, then plasterboard/fireboard. So with this current setup I have zero space for downlights.

 

I have seen various ways around this from cutting a big hole in the insulation, which seems daft (and possibly against building regs) to put in expensive insulation then cut a hole in it for heat to escape. Or I could lower the ceiling, but the edges of the ceiling will be 2.15m as is so if I drop in another 100mm or so it's going to get cramped. 

 

I have also seen these which look like they need less space, but I am not sure whether I need to buy fire rated ones;

http://www.ebay.co.uk/itm/LED-Recessed-Flush-Mounted-Ceiling-Slim-Panel-DownLight-Round-Square-Top-Quality-/111782066218?var=&hash=item1a06baf82a:m:mXUXDG5WbO_Zkd4d6DRsv0A

and these;

http://www.iq-ecolight.com/iq-products/led-light-fittings/flood-downlights/15w-led-commercial-downlight

 

 

 

Any ideas on how I should go about lighting this?

 

Cheers,

 

Dean

[Kit Car Electronics and Essex AO]

Can't you just fit them in the area with the collar ties?

[Greggs]

As Mike says above, or have you thought about uplighting? Around the perimeter, or a combination of both..

Will it be a kitchen?

Greggs,

[Deanspoors]

I could light it from the centre, but don't think it will look very good, but then again if it's going to save me pulling my hair out then it might be the best option. It's going to be a gym Greggs.

[Mark (smokey mow)]

Dean, i'm short of time to reply over breakfast but feel free to give me a call at work and I can talk you through a few options

http://www.colchester.gov.uk/article/13429/Building-Control-Surveyors-Areas

[Deanspoors]

Thanks for the offer Mark, but I'm currently offshore of Russia. I'll be home on the 18th if I can call then.

 

Thanks,

Dean

[Mark (smokey mow)]

Thanks for the offer Mark, but I'm currently offshore of Russia. I'll be home on the 18th if I can call then.

Thanks,

Dean

thats fine I wasn't sure if you were in a hurry and needed to start insulating now.

I might have had enough time to reply to the post by the 18th !

[Darrell O'Neill]

Using quality LEDs will remove the need for surrounding air space. But even so, make sure there is plenty of air flow in the roof structure. I have seen even LEDs 'sweat' when used.

Personally I try and avoid them in pitched ceilings with solid insulation. You really would be best off putting something on the horizontal bit.

Maybe even 'tilt' type so it projects over the whole floor space. Another option is very thin LEDs circular panels ( these are only something like 16mm thick) and come in various sizes and output.

Don't forget whatever u fit, they will have to be fire-rated for building regs.

Try to avoid the slopes if the insulation is solid, otherwise choose carefully.

Oh, and with 25+ yrs in the trade, I've fitted thousands....

[Rory's Dad]

Darryl - why do they need to be fire rated for BR approval??

[Dave Eastwood (Gadgetman) - Club Chairman]

I was told that every opening I made/specified on the current job, in a ceiling, had to have a fire rated "filling" or cover to meet the current building regs. (By the builders, who were fairly helpful and obliging generally, so gave no reason to disbelieve them).

All the down lighters we spec'd for the lighting control system were fire rated, and all the ceiling speakers had to have fire hoods.

[Mark (smokey mow)]

Downlighters only need to be fire rated when installed into a ceiling that has a floor above it. If the downlighters are installed into a ceiling that does not have a floor above it (as is the case with Dean's extension) then these don't need to have a fire rating.

The reason for this is that floors within dwellings have to have 30 minutes fire resistance for Insulation, Integrity and loadbearing capacity from their underside. This ensures that should the worst happen and you become trapped on an upper floor by fire, you are protected for at least 30minutes from the affects of heat from the fire below the room, 30 minutes where the floor and ceiling will retain their integrity and thirdly 30 minutes where the floor will continue to perfom its structural function. a 12.5mm thickness of plasterboard with a 3mm skim coat of plaster is sufficient to provide this 30minutes FR, however each and every hole made in that ceiling will compromise its fire resistance, so these will need to be filled eiter with intumescent seals or Fire Rated fittings.

Its also worth noting when talking about fire rated light fittings, that their FR rating is only in relation to maintaining the fire resistance of the ceiling, the FR rating does not mean that the fitting will not set fire to the insulation or timber within the roof if the manufactuers specified clearances to the light fitting have not been observed.

PUR insulation will burn, so it is important to ensure that it is kept clear of hot fittings. This however does sometimes create a conflict with the Building Regulations and maintaining the continuity of insulation as its not uncommon to see large uninsulated voids left around downlights in vaulted ceilings.

These uninsulated voids are a bad idea for several reasons: firstly the room will not be as well insulated and heat will be allowed to escape through the uninsulated areas. Condensation occurs where the hot air from the room meets the cold external air, this is at the back of the light fitting. Finally the breather membrane on the roof will not perform as intended, as the pores within these are not able to cope with large volumes of warm saturated air.

Personally I don't feel that downlighter are a good idea for vaulted ceilings, although I do see plenty. I would normally reccomend either wall lights, or downlighters only within the ridge where there is more space. The insulation manufactuers all reccomend counter battening the ceiling to create a void large enough for the light fitting so the insulation layer isn't compromised.

If there is a strong desire to fit downlighters then I would always ask for a minimum of 50mm PUR insulation behind the light fitting to minimise the risk of condensation. this is something that would need to be agreed with Building Control though as other surveyors may have differing views to my own.

[Mattt]

LV tension wire spots?

[Deanspoors]

LV tension wire spots?

 

Hi Mattt, I looked into these, but the manufacturers said that these were designed for 6m runs maximum, and the width of the room is 8m.

 

 

Downlighters only need to be fire rated when installed into a ceiling that has a floor above it. If the downlighters are installed into a ceiling that does not have a floor above it (as is the case with Dean's extension) then these don't need to have a fire rating.

The reason for this is that floors within dwellings have to have 30 minutes fire resistance for Insulation, Integrity and loadbearing capacity from their underside. This ensures that should the worst happen and you become trapped on an upper floor by fire, you are protected for at least 30minutes from the affects of heat from the fire below the room, 30 minutes where the floor and ceiling will retain their integrity and thirdly 30 minutes where the floor will continue to perfom its structural function. a 12.5mm thickness of plasterboard with a 3mm skim coat of plaster is sufficient to provide this 30minutes FR, however each and every hole made in that ceiling will compromise its fire resistance, so these will need to be filled eiter with intumescent seals or Fire Rated fittings.

Its also worth noting when talking about fire rated light fittings, that their FR rating is only in relation to maintaining the fire resistance of the ceiling, the FR rating does not mean that the fitting will not set fire to the insulation or timber within the roof if the manufactuers specified clearances to the light fitting have not been observed.

PUR insulation will burn, so it is important to ensure that it is kept clear of hot fittings. This however does sometimes create a conflict with the Building Regulations and maintaining the continuity of insulation as its not uncommon to see large uninsulated voids left around downlights in vaulted ceilings.

These uninsulated voids are a bad idea for several reasons: firstly the room will not be as well insulated and heat will be allowed to escape through the uninsulated areas. Condensation occurs where the hot air from the room meets the cold external air, this is at the back of the light fitting. Finally the breather membrane on the roof will not perform as intended, as the pores within these are not able to cope with large volumes of warm saturated air.

Personally I don't feel that downlighter are a good idea for vaulted ceilings, although I do see plenty. I would normally reccomend either wall lights, or downlighters only within the ridge where there is more space. The insulation manufactuers all reccomend counter battening the ceiling to create a void large enough for the light fitting so the insulation layer isn't compromised.

If there is a strong desire to fit downlighters then I would always ask for a minimum of 50mm PUR insulation behind the light fitting to minimise the risk of condensation. this is something that would need to be agreed with Building Control though as other surveyors may have differing views to my own.

 

Thank you Mark on a comprehensive reply, I think I will go with your recommendation and install directional down lights into the ridge area only. It looks like that will be by far the easiest option.

 

Thanks,

Dean

[Andy (Sycho)]

I may be wrong but I presume you have a steel in the ridge, its my understanding that that should be fire proofed so if you haven't protected it with paint or another method you will still need fire rated downlighting & I don't think you can get directional downlight which fire rated.

[Paul Hurdsfield - Joint Manchester AO]

Have you thought about some perimeter lighting?

Form a 'pelmet' along the two long sides then drop a rope light or strip LEDs or something similar along them  ,