Lath and plaster ceiling question

[PaulJM]

Hi All,

DIY'er here!

I plan to take down a knackered L&P ceiling where its already sagging quite badly.

My question is....do the laths all need to come down too? I'm assuming that as the plaster is already detached from the laths, it will come down easy peasy leaving the laths in place.

Am I able to plasterboard right over the laths or should should they all come down so I can board right against the joists?

Many thanks!

 

[SFK]

Paul,
I found laths have to also come down as they curve in all directions and are all different thicknesses.
You then have to remove all the nails that held the laths in place.
Hopefully you also know that this is an unimaginably massively dusty job.

I only had access from below, so I recommend:
1) best dust mask and sealed eye protection you can get (think swimming googles)
2) Tarp on floor to stop some of the dust from getting between floorboards (and into grain of floorboards).
3) Tape up doors to stop dust getting into other rooms
4) If you cannot kick ceiling down from above, I used a large crowbar to hook several laths, and then swung on crowbar to pull it down.
EDIT Actually it is was Wreaking-Bar I used as it has a curved end like these: https://www.toolstation.com/search?searchstr=83372 66571 35590 55633
5) A shovel and builders baskets to pick up debris.
6) Crowbar to pull out all the nails.

Then
A) Consider if you need to put in noggins between joists to strengthen floor above and/or to assist screwing plasterboard to.
B) Consider if you need to put noggin or sheet of ply between joists where ceiling light will be to take weight of heavy lights.
C) Consider if you wish to use fire rated (red) plasterboard if there is a habitable room above.
D) Push light cable through plasterboard so you do not forget where it is later.

SFK

 

[PaulJM]

Hi SFK,

Thanks for the info. I thought that might be the case with the laths.

Directly above is the loft so I can get up there and kick it down. I've got a P3 dust mask and sealed goggles but I am dreading the mess. We did a full rewire a few years ago and we were hoovering every day for weeks!

I've heard this THE messiest job you can do in any house so I'm not massively looking forward to it. I have two large windows that I could prop turbo fans in front of to help get rid of the dust....would this be worthwhile?

Thanks,
Paul

 

[SFK]

Paul,
For me plaster from ceilings was worse than walls because there was also a (thankfully thin) 100yr old layer of sticky soot on the top of the ceiling (ie between the joists) which I presume was from when the coal fires were in constant use. This black dust added to the mess.

I also hated separating the the laths (which are full of nails) from the plaster. Good thing was that the local tip said the lime plaster was 'rubble' and not 'new plaster' and so this was a big cost saving (as here it costs a lot to take plaster sheets offcuts to local tip).

But I am getting off topic. In principle I think the fans in the window are a great idea. But in practice I can imaging my lawn and neighbors houses gaining a thin white coating of plaster!
:> I did close all other doors in house and put tape around outside of these. And had plastic sheet hanging on outside of door of room I was working in and I put masking tape around the doors once I entered the room (take in water in bottle and chair) and then did not leave room until all was pulled down.

But in the end it was an okay and dry job. And gives you good feeling of satisfaction once room is cleared and joists are visible and clean.
Good luck,
SFK

 

[endecotp]

Regarding fans, I’ve experimented with a bathroom extractor fan temporarily fitted in the window, in a sheet of hardboard that’s a tight fit to both - with ducr tape. (Easy in a sash window, harder otherwise.). The idea is not so much that it will extract much dust, but more just to ensure the air flow under the door is always slightly into the room, hence reducing the amount of dust that escapes into the rest of the house.

I can’t really comment on whether it works, since I don’t know how much worse things would have been without.

 

[23vc]

How about cross battening with chunky 25x50 battens screwed (with decent size long screws) securely into the joists which should pull up any sag. Then board over the battens. Just thinking of alternatives to having to take it down

 

[roy c]

You could also have a hose pipe up there and spray it as you knock it off !!!

 

[Tigercubrider]

no idea if it works but in the days of DIY books ( rather than videos on youtube) they said that a ceiling could be pushed back up with a 2x4 and a sheet of timber on top.
Then more wet plaster was used from above to bond the ceiling back in place?

 

[JohnD]

It can work, and I have done it, but you have to first hoover the top of the ceiling clean from above, and pick out all the broken nibs, as they are liable to get between the plaster and the laths or joists, and prevent it lifting up smoothly.

You can screw expanded metal lathing to the joists so that your pour of new plaster grips to that, and to the old ceiling, for more dependable support. The old nails in the laths are often rusted and broken.

 

[23vc]

I’ve gotta do the same soon for my sister and I’m planning on doing what I said above with decent size battens. There’s no way I’m pulling it down if I can avoid it. The height reduction won’t be an issue. I’ll try to remember to report back on the outcome

 

[oldbutnotdead]

If the loft is above and you plan on storing substantial Stuff up there you could do what I did years ago- installed 2" x 10" joists parallel with the existing (probably 4 x 2 or 3 x 2) old saggy timber then jacked the ceiling up with a pair of acros and a bit of 4 x 2 till the sag had gone then screwed through the old joists into the new ones. Finally boarded over the old ceiling (it was cracked but otherwise reasonable) and skimmed. Main pain was marking where the joists were and screwing without hitting lath nails (screwing into the 2" x 10" would have been iffy cos I'd packed it up by 10mm with slate to prevent the nibs above the laths fouling them)