DIYbanter - View Single Post - Advice on bathroom lighting in shallow false ceiling

wrote:

We're still mulling over ideas for the lighting in the refurbished
bathroom at our flat.

The basic plan is now fairly well defined, six downlighters in a false
ceiling which we will put up. The existing ceiling is quite high and
is concrete or similar so making holes in that for downlighters is out.

How much light should one need in a 2.5 metre by 1.5 metre bathroom
with virtually no outside light (it just has a narrow window onto a
stairwell)? I guess the choices are 6 x 20 watt, 6 x 35 watt or 6 x
50 watt.

We're thinking of using MDF for the ceiling rather than plasterboard
on the basis that it will be easier to work with and it might be more
practical to make one or two panels removable for access. Does this
sound like a good idea or not?

What's the minimum depth that downlighters need? I'm a bit worried
about the heat in the (small) void between the downlighters and the
real ceiling. I've no worries about the real ceiling being flammable
as it's cement or something similar but what about the MDF and the
battens used to hold it etc.?

Any comments on whether mains or low voltage downlighters would be
better? A couple of them need to be IPx4 and I can't find many
downlighters that quote the IP rating. In addition we'd like two
matching (or at least similar) eyeball (i.e. swivelling) downlighters
for above the washbasin.

I'd go for 6x50W as the bulbs are a bit more robust.

300W spread over the area of the ceiling - 3.75 sq meters - is less than
100W/sq meter. That is about what my underfloor heating kicks out at
full crack. If you are worried, use plasterboard rather than MDF. That
will take a deal of heat. Or even Masterboard (multiboard) which is
'asbestos replacement' board

If you are worried about heat also, youi could run fat '50A' cable from
a remote toroidal to the lights rather than tuck transformers up in the
void. I'd avoid electronic transformers vbeacuse of the possibility of
damp,. and the blasted buzzing they produce.

Use the special bathroom fitments where spalshing is likely.