Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David

On Sun, 01 Nov 2009 17:43:41 +0000, David J wrote:

Is this space really neccesary? Is fibreglass insulation inflammable?

No but your light fittings won't like being self-cooked even more than
allowed for in the strictly marginal design-down-to-the-last-penny and are
likely to fail even sooner than they might otherwise.


--
John Stumbles

Hypnotising Hypnotists Can Be Tricky

On Sun, 01 Nov 2009 17:43:41 +0000 someone who may be David J
wrote this:-

However the main bedroom has 5 flush mounted light fittings in the
ceiling,

That's the problem, crappy light fittings. These nearly always
produce uneven light, which is mostly directed at the floor. Useful
for illuminating a romantic tussle, but not much else. Removing them
and replacing them with something more useful for providing general
lighting is the best solution.

and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

You don't say what sort of lamps are installed in these crappy
fittings.

Is this space really neccesary?

I imagine the answer you want to hear is, no. However, the answer is
yes, except in unusual conditions which are most unlikely to apply
here.

Is fibreglass insulation inflammable?

Inflammable is a word the meaning of which can be confused.
Flammable and non-flammable are better words to use.

Is it OK for me to lay my extra layers over these voids?

To make up for the poor light distribution these sorts of fitting
tend to have high powered lamps in them, which give off a lot of
heat. If you insulate over them the insulation probably won't catch
fire, but you will shorten the life of the lamps dramatically as
they will overheat. You may also cause parts of the fitting to melt.

There is another question. What sort of cable is used to the
fitting? If it is ordinary twin and earth this is likely to melt if
overheated. The twin and earth should terminate near the fitting and
a heat resisting cable run to the lamp. Even that will only resist a
certain amount of heat.

There are flowerpot like hoods which can be fitted over these
contraptions. They are intended to keep insulation away from the
fittings, not to allow it to be run over them.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000...#pt3-pb3-l1g54

"David J" wrote in message
...
Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David

If you don't think it is a requirement to leave a gap simply cover it up.

David Hansen wrote:

However the main bedroom has 5 flush mounted light fittings in the
ceiling,

To make up for the poor light distribution these sorts of fitting
tend to have high powered lamps in them, which give off a lot of
heat.

Is it possible to get low-energy replacements for these ceiling lights?

--
Timothy Murphy
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

On Sun, 1 Nov 2009 18:44:52 -0000, "Roger"
wrote:


"David J" wrote in message
.. .
Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David

If you don't think it is a requirement to leave a gap simply cover it up.

Well, these lamps are all 240v 40W K1 spotlights. As most of the 40W
is light and is ventilated into the bedroom, that leaves just a small
fraction of the wattage in heat that will rise vertically into the
loft. So how much air space does that need to disipate itself?

Since most of the time the lights are off and the real issue is cold
entering the bedroom from the loft, my thinking is that an extra layer
of glass fibre insulation over these existing voids would not cause a
problem either to the lamps or to the fibre glass.

Removal of these particular lamps is a possibility, but the existing
holes would leave a nasty scar on the ceiling.

The comment provided above is smart but not particularly helpful...

David

David J wrote:
On Sun, 1 Nov 2009 18:44:52 -0000, "Roger"
wrote:

"David J" wrote in message
...
Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David
If you don't think it is a requirement to leave a gap simply cover it up.

Well, these lamps are all 240v 40W K1 spotlights. As most of the 40W
is light and is ventilated into the bedroom, that leaves just a small
fraction of the wattage in heat that will rise vertically into the
loft. So how much air space does that need to disipate itself?

Most of that 40W is heat leaving just a small fraction as light....

--
Eiron.

On Sun, 01 Nov 2009 23:39:23 +0000, David J wrote:

Well, these lamps are all 240v 40W K1 spotlights. As most of the 40W
is light and is ventilated into the bedroom, that leaves just a small
fraction of the wattage in heat that will rise vertically into the
loft. So how much air space does that need to disipate itself?

Light doesn't need ventilation, heat does. Most of the 40W will be heat, a
minute fraction of that actual light power.

--
John Stumbles

Pessimists are never disappointed

On Sun, 01 Nov 2009 17:43:41 +0000
David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David

You've got to let the heat out somehow. Put a big terracotta flower pot
over each lamp and insulate right up to it, but not over it.
R.

On 01/11/09 23:39, David J wrote:

The comment provided above is smart but not particularly helpful...

It was from the well known (and best ignored) "Tiscali Idiot".

On Sun, 01 Nov 2009 21:54:57 +0000 someone who may be Timothy Murphy
wrote this:-

Is it possible to get low-energy replacements for these ceiling lights?

Unless the fittings will only take low energy lamps it is reasonably
foreseeable that someone will replace them with incandescent lamps
in the future, which must be allowed for.

Anyway, low energy lamps are not all equal. For example, compact
fluorescents give off more heat than LEDs.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000...#pt3-pb3-l1g54

On Nov 1, 5:43*pm, David J wrote:
Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.


AIUI, in these highly regulated times, you must either add a further
180mm or none at all. By adding just 100mm you have "interfered with
a thermal unit" so you must bring it up to current building regs
(280mm); it's not enough just to improve it. Adding loft insulation
is a building control matter, so there will also be a £100 or so to
pay for the BC application and inspection.


Robert

On 2 Nov, 09:38, RobertL wrote:
On Nov 1, 5:43*pm, David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

AIUI, in these highly regulated times, *you must either add a further
180mm or none at all. *By adding just 100mm you have "interfered with
a thermal unit" so you must bring it up to current building regs
(280mm); *it's not enough just to improve it. *Adding loft insulation
is a building control matter, so there will also be a £100 or so to
pay for the BC application and inspection.

Robert

Depending on how far up for arse your head is, of course.

Cheers
Richard

On 2 Nov, 15:07, geraldthehamster wrote:
On 2 Nov, 09:38, RobertL wrote:

On Nov 1, 5:43*pm, David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft..

AIUI, in these highly regulated times, *you must either add a further
180mm or none at all. *By adding just 100mm you have "interfered with
a thermal unit" so you must bring it up to current building regs
(280mm); *it's not enough just to improve it. *Adding loft insulation
is a building control matter, so there will also be a £100 or so to
pay for the BC application and inspection.

Robert

Depending on how far up for arse your head is, of course.

Cheers
Richard

That should have been "your arse".

geraldthehamster wrote:

On 2 Nov, 15:07, geraldthehamster wrote:
On 2 Nov, 09:38, RobertL wrote:

On Nov 1, 5:43*pm, David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

AIUI, in these highly regulated times, *you must either add a further
180mm or none at all. *By adding just 100mm you have "interfered with
a thermal unit" so you must bring it up to current building regs
(280mm); *it's not enough just to improve it. *Adding loft insulation
is a building control matter, so there will also be a £100 or so to
pay for the BC application and inspection.

Robert

Depending on how far up for arse your head is, of course.

That should have been "your arse".

Houses are bought and sold 'as is', and they don't need to meet any
particular standards at the time of sale. The thing is not to lie
about its condition when selling - but all that might be needed is an
adjustment of the price, or the taking out of a 'building regs'
insurance policy, which apparently aren't all that dear.

SWMBO and I spent three sessions in the loft increasing the insulation
from 25mm to 125mm,and it was such fun we won't be rushing back to add
any more.

Our inefficient back boiler manages to keep this smallish 3-bed
sixties jerry-built semi warm, with the lounge at 23 degC, for a
whopping cost of £500 a year at current rates. I have no intention of
spending £1000s on Class A boilered replacement system.

On Mon, 02 Nov 2009 15:49:45 +0000, Terry Fields
wrote:


geraldthehamster wrote:

On 2 Nov, 15:07, geraldthehamster wrote:
On 2 Nov, 09:38, RobertL wrote:

On Nov 1, 5:43*pm, David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

AIUI, in these highly regulated times, *you must either add a further
180mm or none at all. *By adding just 100mm you have "interfered with
a thermal unit" so you must bring it up to current building regs
(280mm); *it's not enough just to improve it. *Adding loft insulation
is a building control matter, so there will also be a £100 or so to
pay for the BC application and inspection.

Robert

Depending on how far up for arse your head is, of course.

That should have been "your arse".

Houses are bought and sold 'as is', and they don't need to meet any
particular standards at the time of sale. The thing is not to lie
about its condition when selling - but all that might be needed is an
adjustment of the price, or the taking out of a 'building regs'
insurance policy, which apparently aren't all that dear.

SWMBO and I spent three sessions in the loft increasing the insulation
from 25mm to 125mm,and it was such fun we won't be rushing back to add
any more.

Our inefficient back boiler manages to keep this smallish 3-bed
sixties jerry-built semi warm, with the lounge at 23 degC, for a
whopping cost of £500 a year at current rates. I have no intention of
spending £1000s on Class A boilered replacement system.


Final update on the issue.. ... and thanks for all the comments.

I was wrong about the lamps in use in my bedroom. I took one out, and
they are actually 12V 20W BAB Halogens. There must be a mains Tx up
there in the loft somewhere. So the waste heat being generated up
there is even less than I thought. I'm going to take up TOF's
suggestion of using a plantpot over each unit and insulate around it.

I picked up some more loft insulation at B&Q today in their 2 for 1
offer. Excellent value at about £1/square M.

It's amazing what can be made out of old wine bottles, isn't it?

David

David J wrote:


I picked up some more loft insulation at B&Q today in their 2 for 1
offer. Excellent value at about £1/square M.

It's amazing what can be made out of old wine bottles, isn't it?

LOL

I do my best to help....I put out about 25 every month for recycling.

"TheOldFellow" wrote in message
. ..
On Sun, 01 Nov 2009 17:43:41 +0000
David J wrote:

Checking out the loft insulation in a recently purchased house, I
found the builder had installed the regulation 100mm (house built
about 1997) so I have added another 100mm layer over most of the loft.

However the main bedroom has 5 flush mounted light fittings in the
ceiling, and the installer had cleared an open space in the insulation
above each light, presumably to allow for the lamp heat to escape.

Is this space really neccesary? Is fibreglass insulation inflammable?

Is it OK for me to lay my extra layers over these voids?

David

You've got to let the heat out somehow. Put a big terracotta flower pot
over each lamp and insulate right up to it, but not over it.

Cut a notch in the rim to get the cable in and seal with a silicon bead.
Seal up the hole in the bottom.