Lath and plaster ceiling / new light fittings

[clueless1]

Hi
My late 1920s house has lath and plaster ceilings, all sound and in good condition. I would like to replace the ceiling lights with haolgen spots but am not sure if this is possible in lath and plaster ceilings - can anyone advise please?

many thanks

 

[plugwash]

i can't see why you couldn't fit them although you would have to take great care when making the holes.

 

[clueless1]

Yes, this is one of the things I am concerned about! Is there any hope of lathes unsupported at two new ends (created by cutting through to install the spotlight) staying up?

The other concern is the likelihood of the plaster containing horsehair and the associated fire risk......

Any thoughts?

 

[ban-all-sheds]

Yes, this is one of the things I am concerned about! Is there any hope of lathes unsupported at two new ends (created by cutting through to install the spotlight) staying up?

Try the Building Forum?

The other concern is the likelihood of the plaster containing horsehair and the associated fire risk......

Use 'F' marked luminaires.

 

[Giles]

Not sure there would be horse hair in a 1920s

Just removed a celing in my 1902 House, and it didn't have any horse hair....just very crumbly mortar and black soot!

I think you can get a special drill but for drilling the holes for downlights...this may go through the plaster and lathes...the lathes are pretty solid being nailed to several joists.

 

[fireman22]

dont go there tried and failed unless your very lucky

 

[Lectrician]

A normal by-metal hole saw will sort you out - I would use F type fittings, these are not usually readily available in ELV (from my wholesalers anyway).

 

[felix]

I've had to cut holes in lath and plaster before. Laths that are cut right through tend to flap around behind and there's a risk of the plaster crumbling.

One way out is to put a disc of plywood/plastic/metal/anythingyoulike between the light fitting and the ceiling. You cut your nice round hole in this then here comes the clever bit. Before you cut the big hole in the plaster you put small, countersunk screws through disc and plaster and into the laths. This will anchor them and trap the plaster between lath and disc. Now you can cut that hole with relative impunity. The only difficult bit is locating the actual laths. You will need to do some test drillings first.

 

[clueless1]

Thank you all for your input - I think I will give it a go using Felix's suggestion. Fingers crossed.....

Can someone tell me more about F type fittings please? I'm guessing that this is some sort of fire hazard / safety rating?

 

[ban-all-sheds]

It means that they are safe to be mounted on normally flammable surfaces.

 

[Adam_151]

It means that they are safe to be mounted on normally flammable surfaces.

Shouldn't they be C marked (for combustable surfaces)

Petol is flammable, wood is combustable, (as far as I know, anyway)

Anyway, thats beside the point, F marked is what they are, incorrectly or correctly

 

[Beefcake daddy]

I'm about to do the same thing, same problem - lath and plaster is in bad shape in mine. I've got 6mm mdf to put in from above, fixed to joists, screwed into through laths then hole cut through both. My only worry is that my lights say the maximum thickness of ceiling they can go through is 25mm, hoping they'll still fit!

How did you get on with yours?

 

[clueless1]

I haven't attempted it yet........ I'll let you know when I do and I'd be interested to hear how you get on too. Fingers crossed for both of us!

 

[Beefcake daddy]

cool, shouldn't be long before I start. Just got to fit my shower first so at least I can clean up when the whole lot comes down on my head!

 

[Beefcake daddy]

Right, just put mine in as plasterer comes in the morning so had to bite the bullet.

The whole supporting the laths with board went out the window, couldn't be pestered with it! I just got a new holesaw blade and drilled straight through the laths, worked fine! I wouldn't have got away with it if it had been my kitchen ceiling though, it's in a far worse state. This one had some pretty major cracks running through it but the bulk of it was ok.