downlights and flower pots

[bluebirdnick]

As I said in my other thread, I am retrofitting MVHR in my 1930s house. We have done quite a bit to improve the airtightness, mostly as a happy side-effect of the other work we have done, but I am now looking at what I can do specifically to improve airtightness. I know this is possibly a futile project given the age of the house and the construction methods used, but I still want to do as best I can with it. One of the big issues is that we currently have a cold loft. This will change next year when we extend into it, but for now it is a cold loft. All ceilings beneath have been boarded over and re-skimmed, and a vapour barrier installed on the cold side. Which is all very good, but then we go punching holes in it to fit downlights - about 25 in total.

 

What can I do to mitigate the impact that these have on airtightness? The electrician has used fire rated units that take LEDs so tells me I need no "caps" above them in the loft space to shield them from the thermal insulation above, but presumably I can/should do so? You can buy plastic loft caps that look like they would be airtight, but they are very expensive for what looks like a very basic product. Would a basic upturned terracotta flower pot do the trick? And if so, presumably I would have to cover the hole in the bottom? I'd probably seal around the bottom of it too, just to make sure. I can't see why this shouldn't work, but have a nagging concern about moisture in the wet rooms getting trapped in the flower pot and condensing on the light. 

 

And what to I put above the smaller holes made by ceiling roses and other light fittings? And cables from switches etc where they come up from below? I'll be changing the loft hatch too (We need a new one anyway). 

 

Any thoughts welcome! Thanks.

[Declan52]

I used plant pots for mine. You will need to notch out enough on the lip of the pot for the cables. I used silicone and some airtightness tape to fill in the hole in the bottom of the pot and then used silicone to stick the pot to the plasterboard.

For the rest of the holes I used silicone and airtightness tape. 

Don't forget the conduit at every plug, light switch etc will also need sealed up.

The easiest way to check what you have done is to light a candle and walk round the house watching to see if it flickers as you put it up to all the bits you have sealed up.

Or you could use surface mounted led lights instead.

[Miek]

Airtight expanding foam might help you. 

 

fm330

 

 

[Russell griffiths]

I made plasterboard boxes to go over mine. 

[Onoff]

Your best bet, pre skimming and depending on the impact on room height, might have been counter battens to create a service void then another layer of pb as the finished ceiling. Then low profile LED panels.

 

With hindsight I should have done that. I have Thermahoods.

 

 

 

 

[tonyshouse]

Clay/terracotta flower pots 

[MJNewton]

If the fittings are fire rated aren't they already airtight (sufficiently so for what's required here at least)? 

[dpmiller]

31 minutes ago, MJNewton said:

If the fittings are fire rated aren't they already airtight (sufficiently so for what's required here at least)? 

 

Probably not as fire-rated means sealed in the event of fire,  so often with vents and intumescent material

[dpmiller]

to the OP are you looking for focussed pools of light or diffuse light from above? If the latter, then the slim LED panels  fit within the PB layer, but you'll need a bit of space above (slack membrane between joists) for the clips and driver.

[MJNewton]

3 minutes ago, dpmiller said:

 

Probably not as fire-rated means sealed in the event of fire,  so often with vents and intumescent material

 

Ah okay. The ones I've been looking at (Integral Evofire) are sealed by the bezel on the ceiling side and have a piece of glass over the bulb. I guess they use different methods by the sounds of it. 

[Carrerahill]

1 hour ago, Onoff said:

Your best bet, pre skimming and depending on the impact on room height, might have been counter battens to create a service void then another layer of pb as the finished ceiling. Then low profile LED panels.

 

With hindsight I should have done that. I have Thermahoods.

 

 

 

 

LED panels! It ain't an office!

 

 

[Carrerahill]

46 minutes ago, dpmiller said:

to the OP are you looking for focussed pools of light or diffuse light from above? If the latter, then the slim LED panels  fit within the PB layer, but you'll need a bit of space above (slack membrane between joists) for the clips and driver.

Again, this mention of panels!

 

Do you, @dpmiller and @Onoff know what an LED panel is?

 

This is a panel...

 

[joe90]

Or https://www.ebay.co.uk/itm/LED-Ceiling-Light-Round-Panel-Down-Lights-Bathroom-Kitchen-Living-Room-Wall-Lamp/283782887813?_trkparms=ispr%3D1&hash=item4212c73985:m:mVeG8bdHNC4IlW-dO2MdtPA&enc

 

or you can get them that fit flush with the plasterboard and barely thicker than the plasterboard!

Edited June 1, 2020 by joe90

[Carrerahill]

14 minutes ago, joe90 said:

Or https://www.ebay.co.uk/itm/LED-Ceiling-Light-Round-Panel-Down-Lights-Bathroom-Kitchen-Living-Room-Wall-Lamp/283782887813?_trkparms=ispr%3D1&hash=item4212c73985:m:mVeG8bdHNC4IlW-dO2MdtPA&enc

 

or you can get them that fit flush with the plasterboard and barely thicker than the plasterboard!

That isn't a panel and never has been though, that is a low profile down-light. That is a case of someone calling it a panel because it is thin but it is not more a panel than a search-light.

 

If you want diffused light there are far better ways of achieving it while keeping a smart domestic look, multifaceted reflectors or etched diffusers etc. even some GU10 lamps now come with an optic system which will give uniform distribution without the tight beam angles and sharp cut-offs. 

 

 

 

 

 

 

[Onoff]

46 minutes ago, Carrerahill said:

Again, this mention of panels!

 

Do you, @dpmiller and @Onoff know what an LED panel is?

 

This is a panel...

 

 

Yes and neither of us meant that! ?

[dpmiller]

I don't care what shape it is, it's still the same tech- an edge-lit panel.

[bluebirdnick]

Thanks all.

 

27 minutes ago, dpmiller said:

to the OP are you looking for focussed pools of light or diffuse light from above? If the latter, then the slim LED panels  fit within the PB layer, but you'll need a bit of space above (slack membrane between joists) for the clips and driver.

 

The former. But the downlights are already installed. I am personally not a fan of them because as you suggest, they are a bit rubbish at providing even lighting in a room, but my wife likes them and it wasn't something I felt so strongly about. 

 

2 hours ago, Miek said:

Airtight expanding foam might help you. 

 

fm330

 

 

Thanks - I assume you mean for sealing up the hole in the pots? I actually have a can or two of this left over from a previous sound insulation project.

 

1 hour ago, Onoff said:

Your best bet, pre skimming and depending on the impact on room height, might have been counter battens to create a service void then another layer of pb as the finished ceiling. Then low profile LED panels.

 

With hindsight I should have done that. I have Thermahoods.

 

 

 

 

I do actually have that above the new en suite, but not in all rooms. I've not got two layers of plasterboard though, and it would be near-impossible to fit it from above now.

 

So it seems that flower pots (or plasterboard cubes) would do the trick. For those that fitted them - what size did you use? thanks