Replacing damaged lathe and lime ceiling?

[Pogonation]

I think it would be both airborne noise and footsteps. It’s worth noting that with the current thick lime ceiling without insulation I hear nothing. I think the mass and rockwool would be very good for airborne noise and hopefully the dampening effect of the vinyl inbetween the joists and acoustic board will dampen sound from football as well as possible with the limited depth I have. Do you think this would work?

 

[bobby spray]

Its, a pity that you can’t get access from above. I have repaired a few areas of my own ceilings using a ‘Spanish windlass’ to pull the ceiling into place then reinstating the broken nibs between the laths. It can be a mucky job though!

 

[Lacan07]

Airborne noise is reduced via mass, acoustic wool, plasterboard, etc, and footfall / structural noise can only be reduced by decoupling your ceiling from the joists. If the old lath and plaster was doing a good of keeping the neighbours at bay then anything you add now is a bonus I would have thought. I'm guessing your neighbours are very respectful, I always think noise is very much dependent on who you live next door to. Btw I always thought that green glue stuff had been debunked as a waste of time?

 

[a twig]

At the risk of stating the obvious, if the lath and lime plaster ceiling definitely did the job before, wouldn’t the least risky option be to reinstate it?

 

[MatthewC]

I disagree (to my own surprise).

I did my house almost entirely with traditional techniques, with lime plaster on the walls and upstairs ceilings, and using lime mortar to repair stonework (see http://houseintheenchantedforest.blogspot.com/ if you have an hour or two to spare). In my view it is unlikely that you can do a patch repair on a ceiling because you cannot get a good join and the work you do might loosen the rest, especially if you need to nail a few new laths (hint: drill pilot holes and use screws). We took all of our upstairs ceiling plaster off (one of the worst jobs ever created, probably on a par with cleaning a chimney by climbing up it).

The "almost" is because when we found how bad most of the downstairs ceilings were, it was too late to do a lime repair. This is because you cannot walk on the floor above for a good long time while the lime beneath is curing - a "good long time" being quite undefinable precisely but 3 months is probably not long enough, 6 months might be better. Any walking is likely to upset the set of the lime and give you a ceiling more prone to cracking in future.

So the upshot is that, since the apartment in question has occupants above (who caused the issue in the first place), it is probably impossible to do a lime ceiling beneath them. I doubt insurers would pay for hotels for 3 - 6 months even if the occupants were willing!

As a result we compromised: we used plasterboard for the downstairs ceilings, then painted DG27 onto it (which was recommended at the time as a porous bond) and used some fine lime plaster onto that. It still looks right eleven years later

<pedant>By the way, the word for the ceiling in question is "LATH", not "lathe" which is a metal workshop machine. I congratulate Cubist for being almost the only person who got it right above!</pedant>

 

[Cubist]

<pedant>By the way, the word for the ceiling in question is "LATH", not "lathe" which is a metal workshop machine. I congratulate Cubist for being almost the only person who got it right above!</pedant>

Why, thank you Mr C.

Having, in my youth, been an eager your engineer playing with machines that could pick me up and spit out the bits, I soon learned to respect such turning equipment and use their proper term of address.

 

[malcolm]

It is possible to locally re-plaster in lime once any lath that has caused a problem have been nailed back on. It's also possible to replace lath. Some of the lath in the photo is new. Someone had whacked a hole in the wall. I did similar repairs in the ceiling and there is no reason not to go upstairs while the lime cures. Lime is a bit flexible and new lime even more so.



Lime ceilings are good at drying out after water ingress. The 17C straw plaster in my snug suffered from an overflow from the water tank in the attic while I was in Sweden. It took the lining paper off the ceiling and created a lot of cracks. It dried up. It's not as good as it was but it's still good.



I would be nervous about replacing an old ceiling with modern stuff. It'll lose all the features and will be more prone to damage next time someone messes up with the bath upstairs. For acoustics the damping effect of dissimilar materials can be handy too.

 

[a twig]

<pedant>By the way, the word for the ceiling in question is "LATH", not "lathe" which is a metal workshop machine. I congratulate Cubist for being almost the only person who got it right above!</pedant>

A lathe is also available in other flavours than metal, and at my count there are at least 4 members using lath correctly in this thread, thus your membership of the pedant society is now revoked.

 

[Lacan07]

A lathe is also available in other flavours than metal, and at my count there are at least 4 members using lath correctly in this thread, thus your membership of the pedant society is now revoked.

I also use 'lath' correctly I think, although I may not have mentioned the word in this thread thus far

 

[paulc]

s a result we compromised: we used plasterboard for the downstairs ceilings, then painted DG27 onto it (which was recommended at the time as a porous bond) and used some fine lime plaster onto that. It still looks right eleven years later

I've done the same, but used Febond Blue Grit. It appears to be an acrylic binder similar to DG27, but considerably cheaper. Also seems to let water pass through to the substrate behind quite well.

A lathe is also available in other flavours than metal, and at my count there are at least 4 members using lath correctly in this thread, thus your membership of the pedant society is now revoked.

Wood, spinning, glass, metal of assorted types.. Then there are vertical models as well as the more common horizontal types.
I have been known to abuse the lathes I own for a variety of tasks.

 

[RBailey]

Wood, spinning, glass, metal of assorted types.. Then there are vertical models as well as the more common horizontal types.
I have been known to abuse the lathes I own for a variety of tasks.

OFF TOPIC WARNING
This is one of my favoutire lathes, its one of suppliers at work.

You can see the "tool post" / moving operators cabin on the left hand side.
Just a tad smaller than my Dad's Myford Super 7

 

[Zebra]

I'm with Cubist - breathability doesn't matter on ceilings, just like it doesn't matter on internal walls.

Wood wool boards - ask "Zebra" on here, I think most of the interior of her timber-frame house was done with wood wool boards prior to being lime plastered over, *if* memory serves me rightly.

Oh, well done Feltwell, yes, you're right, I've used woodwool boards extensively for internal plaster work and I think this would be a good compromise here. It would be a relatively easy job to apply the boards over the affected area, it would allow a lime plaster to be blended in with the existing. Only reservation is the thickness. A woodwool board with base coat and top coat might be thicker than lath with base coat and top coat, giving you a problem at the join.
Another option would be lime hemp base coat (instead of haired lime & sand mix) if the laths are still attached. It's easy to apply and is strong once set - which could get around the problem of movement upstairs causing cracking. That's what I used on my living room ceiling as a base coat, with a float coat of lime &sand over the top. I walked around upstairs and don't think it was an issue.

 

[Zebra]

I think you have to brave the mess and have a poke about to see if the laths are reusable, much might depend on that.

 

[Pogonation]

Thanks Zebra, it’s good to know that this wood wool board is an appropriate replacement.. it seems like the entire ceiling has to come down (with the cornicing spared) hence why we were thinking of just blending it all in up to the cornicing. Maybe the old laths are usable but I would rather remove them and pack the space with acoustic mineral for soundproofing so the boards are probably better.

New plasterer has suggested boarding it then using lime hemp on top and then finishing with a marble lime coat (he used this skim on one of my walls and it is perfectly smooth).

The only thing I am thinking at the moment is this will mean I can’t decorate for 3 months (while it sets).. and I can’t get as much mass as using STS board, mass loaded vinyl and acoustic plasterboard. So I’m not sure if just replacing it with modern materials will be the easiest way forwards.

I think you have to brave the mess and have a poke about to see if the laths are reusable, much might depend on that.

 

[Pogonation]

At the risk of stating the obvious, if the lath and lime plaster ceiling definitely did the job before, wouldn’t the least risky option be to reinstate it?

Haha, you are correct but firstly my current neighbour is renting above me and she’s potentially just quiet as a mouse (I think she is) so I could have a future problem if a music enthusiast or a heavy man moves in!

The other thing is that loads of my heat is being used to heat that neighbour above so if I can get the insulation in it will keep my place warmer, save me a bit of money and reduce any noise =)

 

[Pogonation]

I disagree (to my own surprise).

I did my house almost entirely with traditional techniques, with lime plaster on the walls and upstairs ceilings, and using lime mortar to repair stonework (see http://houseintheenchantedforest.blogspot.com/ if you have an hour or two to spare). In my view it is unlikely that you can do a patch repair on a ceiling because you cannot get a good join and the work you do might loosen the rest, especially if you need to nail a few new laths (hint: drill pilot holes and use screws). We took all of our upstairs ceiling plaster off (one of the worst jobs ever created, probably on a par with cleaning a chimney by climbing up it).

The "almost" is because when we found how bad most of the downstairs ceilings were, it was too late to do a lime repair. This is because you cannot walk on the floor above for a good long time while the lime beneath is curing - a "good long time" being quite undefinable precisely but 3 months is probably not long enough, 6 months might be better. Any walking is likely to upset the set of the lime and give you a ceiling more prone to cracking in future.

So the upshot is that, since the apartment in question has occupants above (who caused the issue in the first place), it is probably impossible to do a lime ceiling beneath them. I doubt insurers would pay for hotels for 3 - 6 months even if the occupants were willing!

As a result we compromised: we used plasterboard for the downstairs ceilings, then painted DG27 onto it (which was recommended at the time as a porous bond) and used some fine lime plaster onto that. It still looks right eleven years later

<pedant>By the way, the word for the ceiling in question is "LATH", not "lathe" which is a metal workshop machine. I congratulate Cubist for being almost the only person who got it right above!</pedant>

Thanks Matthew for this. I never considered that people walking around above may disrupt the curing of the lime plaster below. That is their only living room above me where 90% of the movement takes place so it could be an issue!

You are right, I thought it was lathe (as well as the machine which I have operated many times in my life) but I am wrong thanks for correcting me!

 

[Pogonation]

Airborne noise is reduced via mass, acoustic wool, plasterboard, etc, and footfall / structural noise can only be reduced by decoupling your ceiling from the joists. If the old lath and plaster was doing a good of keeping the neighbours at bay then anything you add now is a bonus I would have thought. I'm guessing your neighbours are very respectful, I always think noise is very much dependent on who you live next door to. Btw I always thought that green glue stuff had been debunked as a waste of time?

Thanks Lacan! You are right that the neighbours are very respectful ( at the moment. The 2 flats above mine are rented out so this could change at any point!

I think green glue is a load of rubbish according to the noise experts I have spoken to. Mass loaded vinyl on the other hand is apparently quite effective!

 

[Pogonation]

It is possible to locally re-plaster in lime once any lath that has caused a problem have been nailed back on. It's also possible to replace lath. Some of the lath in the photo is new. Someone had whacked a hole in the wall. I did similar repairs in the ceiling and there is no reason not to go upstairs while the lime cures. Lime is a bit flexible and new lime even more so.

View attachment 9662

Lime ceilings are good at drying out after water ingress. The 17C straw plaster in my snug suffered from an overflow from the water tank in the attic while I was in Sweden. It took the lining paper off the ceiling and created a lot of cracks. It dried up. It's not as good as it was but it's still good.

View attachment 9663

I would be nervous about replacing an old ceiling with modern stuff. It'll lose all the features and will be more prone to damage next time someone messes up with the bath upstairs. For acoustics the damping effect of dissimilar materials can be handy too.

I think you are lucky. The vast majority of my ceiling has delaminated from the laths and is hanging precariously above with no keys holding it in place. I have been told by a few plasterers now that I cannot be saved.

You’re right about features and character, however at the moment it is papered over and looks like any standard ceiling. The beautiful cornicing is where it stands out and these will be retained (hopefully) once the ceiling comes down. I’m not sure plasterboard will massively change the appearance provided the original cornicing work is kept intact as right now it isn’t lumpy really.

 

[Lacan07]

Thanks Lacan! You are right that the neighbours are very respectful ( at the moment. The 2 flats above mine are rented out so this could change at any point!

I think green glue is a load of rubbish according to the noise experts I have spoken to. Mass loaded vinyl on the other hand is apparently quite effective!

Yes, I think I read something similar, apart from anything else the green glue makes no sense whatsoever.

 

[Zebra]

Haha, you are correct but firstly my current neighbour is renting above me and she’s potentially just quiet as a mouse (I think she is) so I could have a future problem if a music enthusiast or a heavy man moves in!

Or a rhinoceros!