Downlights In Lath And Plaster

[pmb515161]

I have a customer who has asked me to install some Downlights to her house. The ceiling is Larve Plaster, I was thinking of installing JCC LED7's but I am concerned about maintaining the fire rating of the ceiling.

The instructions only mention installing in plasterboard and with the wood content of the Larve ceiling and the fact the fire hood will be in direct contact with the wood I don't think I should be fitting them.

I do a lot of work on old houses so any ideas would be greatly appreciated.

 

[Evans Electric]

What is Larve Plaster M8 ? 

 

[pmb515161]

Sorry lath, never really thought about how its spelt...

http://en.wikipedia.org/wiki/Lath_and_plaster

 

[Doc Hudson]

I doubt the Lath & Plaster will be a fire barrier anyway?

Doc H.

 

[sprocketflup]

whooo....deja vu.....

sure this was discussed fairly recently

 

[sprocketflup]

Yep, it was. See what you can glean from this thread fella

http://www.talk.electricianforum.co.uk/topic/21994-lat-and-plaster-with-downlighters/?hl=plaster

Biggest problem I reckon with lath and plaster is getting them cut in and then getting them to sit right afterwards

 

[revjames]

larvae in the plaster - maggots?

 

[pmb515161]

Thanks for the link. I did a search on the forum but it seems I can't spell...

 

[ProDave]

Best of luck cutting a clean round hole in Lath and plaster, and clipping a downlight into it without it all turning to one horrible crumbling mess.

 

[Evans Electric]

Not criticising your spelling PMB , just confused . I of course never smell anything wrong.  :innocent

Right then , answering the question ..... installing LED downlights in a LATH and plaster ceiling .

LED downlights give off very little heat at all so don't worry about that.

Use fire rated fittings  , you can do no more.

Warn the customer that it is possible to drill these ceilings but only if they are solid and sound and don't go ahead if its not .   Fit a track or something.    As Prodave said  , a recipe for disaster.

Most of what I've done were impossible , ceiling breaking up ,  so builders overboarded with p/board and I left large holes in the lath and plaster for the lights.

The heat problem is much reduced now with the LEDS.

Edit;  The other post was for LAT and plaster !  What is it with this stuff?

 

[Riggy]

If the plaster's good (big if!) cut the holes with a jigsaw. Using a holesaw bursts the lath off the back of the plaster causing utter devastation.

Messy and time consuming, but it does work.

 

[steptoe]

Ive recently put 20 downlights and 2x 10" speakers into a lath&plaster ceiling,

no problems whatsoever,

use a really sharp holesaw, it will probably be blunt after about 5 holes BTW,  :|

cut really [REALLY] fast and with very little pressure.

as for the 10" speakers, I drilled a pilot hole then lifted the boards above, marked my hole size and used an imitation Fein,  [ala Clas Ohlson], another blade destroyed, 

then went downstairs and gently cut the plaster with a stanley knife,

job done, 

 

[kerching]

Ah, Clas. Ohlson ...my favourite after the Fein.

I can even fit one and a spare battery in the new Vetopac!

.......just saying!

 

[pmb515161]

Now I feel really foolish after buying a new Battery Fein this morning when I could have got something very similar for a fifth of the price!

I'll go for the 'high-speed-new-holesaw-not-pushing-too-hard' technique I think and keep a plasterer on standby.

 

[steptoe]

Go for short sharp jerks on the 'plaster' as soon as you feel the lath pull back slightly and give it some beans!

does that sound rude? :|

 

[batty]

Agree with Steps invest in plenty of hole saws and allow for them in your price they will be useless once finished. The good thing with LED 7 'S they do have two fixing depths so should be OK for lathe and plaster. I haven't tried them in lathe and plaster let us know how you get on.

 

[Mark2spark]

Yeah I gotta agree with the train of thought to just use brand new hole cutters for lathes. They'll still be sharp enough to get some more use in good old plasterboard afterwards.

The toolstation ones are only a fiver or so.

http://www.toolstation.com/shop/Power+Tool+Accessories/Holesaws/d80/sd1530

 

[chrisg1979]

Agree with Steps, cheapo hole saw, plenty of dust sheets etc shouldn't be a problem and let the hole saw do the work, should get about 4-5 holes per saw but they're only few quid each!

 

[a3]

I fixed the spelling error in the title

 

[Steve3948]

Maybe he's from London, then Larve sounds right