Down Lights in Celotex

[Midwest]

Know this has been debated before, but I'm getting a bit peeved.

Talking of downlights installed in vaulted ceilings, insulated with Celotex or Kingspan. Without ceiling being designed to have a false void to install said down lights, as far as I'm aware there's no way of pyhsically installing downlights without cutting holes into Celotex, which reduce u-value and can create damp in ceiling void.

Last time I checked with my LBC, this was a big no no for them, and they wouldn't pass off building work with such an installation. Celotex & Kingspan say the same. So that's what I've always said when customers have asked for such.

I've just been to quote a job in a property, with a recently finished extension, with a vaulted ceiling full of downlights. Am I missing some recent developments, or are people just going ahead regardless?

 

[sparksburnout]

If it is a sealed void then the builder can (and probably should) use breathable roofing felt.

 

[Midwest]

Have had approval from LBC to install DL in said vaulted ceiling, following site meeting. Arrangements for Celotex/Kingspan as per my reply of email from LBC post 12.

I'm going to use Interceptor Micro's. My problem now is the layout design of the DL's. The vaulted ceiling is quite large, but is populated with three large Velux Integra roof windows, and roof truss's, some of which are doubled up. There's plenty of space for a layout of DL's, just not in the regimented 2 or 3 rows of X amount of DL's.

I've been hunting the web for some pics of similar set ups, but only found one. Does anyone have any sites they could recommend, so I can pinch some ideas? Thinking of a random set up, to light up the floor area of extension.