Downlights in Lath and Plaster ceiling

[Richard Conway]

Hi folks,

I have some downlights that I would like to put in to a lath and plaster ceiling. They are of the variety that have a sprung clip which engages whilst pushing the lights up through the hole in the ceiling. I have fitted these lights to a plasterboard ceiling in the past but was wondering if anyone has any experience in fitting similar lights to a lath and plaster one. Are there any problems I should be aware of?

Any advice appreciated as always.

Cheers, Richard.

[Ali Mac]

I've done this and can't really think of any problems unless you have a particularly thick ceiling. Bit more of a job to cut through, obviously.

Alistair

[Pecanfan]

As Alistair says, bigger job cutting through but not a particular problem - sometimes the laths will just bend / break before they actually cut - sometimes easier to finish off from above if you can. If possible try to clear as much crap from around where the hole will be (from above) before drilling, to keep the mess down (try drilling 100mm holes in a ceiling with

3" of black loft soot above - not a pleasant experience).

Andy

[Andrew Gabriel]

Depends how well the plaster is keyed to the laths. If it's not in too good a state, you'll end up with a lath-and-no-plaster ceiling. What you could try (if you can get access from above) is to pour some dilute PVA over the area to be drilled 24 hours beforehand, which might help bind it togther during the drilling. Not tried this myself, but the thought has occured to me a few times in the past.

Note the lamps must be suitable for use in a combustable ceiling, and make sure you clear away all the wood shavings afterwards. Also, lath and plaster ceilings can be very thick in places, often over an inch in order to get the surface horizontal when the laths/joists aren't. The lamps will need to be able to handle this thickness.

[David W.E. Roberts]

I did a couple like this a few years back:

(1) Clean above the ceiling, including cleaning away the 'tails' of plaster - leaves just the laths from above.

(2) Make up an MDF plate to fit above the ceiling (I think I put ends on to fix to the joists at either side, as well).

(3) Bed the plate onto the top of the laths with runny plaster/plaster of Paris, and fix to the joists.

(4) Once dry and cured, drill and fit as for a plasterboard ceiling.

This has the benefit of strengthening the ceiling for the drilling, and taking the weight of the light fixing on the joists, not the ceiling.

HTH Dave R

[Pecanfan]

Were these particularly heavy downlights? ;-)

Andy

[David W.E. Roberts]

Very little confidence in the original 1930s ceiling.

Not without reason; our dining room ceiling has come down in quite a spectacular fashion, and our next door neighbour currently has a couple of our Screwfix props holding his lounge ceiling up.

I had visions of pushing the light fitting into the (jagged) hole and the whole shooting match coming down.

Lights over the bed should be firmly fixed - don't want waking up by bits of ceiling falling.

So any weight on the ceiling is undesirable.

Also, there is a good chance the hole saw would just rip the laths out of the plaster instead of cutting them.

With a ceiling of that age you need to stabilise everything before trying to cut through it.

Cheers

Dave R