So our ceiling fell down...

[Damon]

Hi everyone

We finally picked up the keys to our new house! A modest norfolk cottage in dire need of restoration and the appropriate love. No doubt i'll be bombarding this place with question after question throughout the process.. That reminds me, does anyone know a good structural engineer in norfolk that's used to working on older buildings?

Unfortunately were welcomed by a big chuck of the ceiling resting on the floor as we walked in for the first time since our last viewing :roll: . I assume that as the house has sat unoccupied and damp for at least 6 months, resulting in the lime absorbing water and becoming heavy and weak. I've had a quick tap about around the rest of the ceiling and it all seems stable, however it does have a "marbled" effect with vein like cracks all over.

The ceiling in question is a lime on lath. The lath that is now exposed is bone dry and there are no damp patches/moisture that we can see. We've been on a mission removing the layers of carpet (5 layers of carpet in some rooms :lol: ) plus layers upon layers of wallpaper to all of the walls whilst airing the place. It is now slowly starting to dry out and already the humidity has dropped from nearly 100% in places a good 10% throughout (relative to ambient humidity)

My question is, how should I go about repairing the ceiling in question?

 

[Damon]

 

[paulc]

how should I go about repairing the ceiling in question?

Are you wanting to do the work yourself or get someone in to do it ?

If the former, grab a bucket or to of lime putty, a few bags of ground chalk, and a lot of hair (or polyester fibres). Mix up a batch of plaster and slap it in - Some will recommend using sand for the first coat or two.

There are a few videos on youtube on the subject of lime plastering - If you can manage common or garden Thistle gypsum plasters, lime isn't that much harder.

Might be worth leaving one carpet down in the affected room. It will save on having to put dust sheets down


Where abouts in Norfolk are you ?
There are a few suppliers of lime products in the county (Hendry over in Foulsham, and CT Baker in Aylsham). Needham Chalk have a couple of quarries in the county, although there are other sources..

 

[Damon]

Thanks for the quick reply. I'm definitely looking to do the work myself. Do you know any mix ratios for the putty mix?

The house is in a small village 15 minutes from Kings Lynn. I'll get looking for a local lime supplier as I think it's always better to source locally if at all possible.

Thanks again

 

[Damon]

Thanks for the quick reply. I'm definitely looking to do the work myself. Do you know any mix ratios for the putty mix?

The house is in a small village 15 minutes from Kings Lynn. I'll get looking for a local lime supplier as I think it's always better to source locally if at all possible.

Thanks again

 

[paulc]

Do you know any mix ratios for the putty mix?

The house is in a small village 15 minutes from Kings Lynn. I'll get looking for a local lime supplier as I think it's always better to source locally if at all possible.

For plaster, there are any number of mixes. Anything from a three to one mix of sand & lime through to three to two - For the first couple of coats, plenty of hair. The final top coat could be a one to one mix of chalk and lime, but no hair and applied very thin.

Needham Chalk have a quarry over at Castle Acre, but I really wouldn't know who to contact in the KL area for lime - With the number of old properties out that way, I'm sure at least one independent building supplier will carry lime putty in stock... West Norfolk Lime over at Hillington might be able to point you in the right direction, just avoid the likes of Travis Perkins (way too expensive. expect to pay around £14 per tub, not the £20+ that TP charge).

 

[plasticpigeon]

Oh dear what a shame. I'm going to guess the marbling is due to moisture, perhaps from stripping wallpaper off the ceiling with a steamer??

I've never lime plastered onto laths, but I am pretty certain that in my circa 1900 house the ceilings were plastered with haired guaged lime, which is lime mortar with gypsum plaster (plaster of paris) and hair in it. The plaster makes it set more quickly and it is slightly stronger. Not sure the purists would go for that but it is an option.

This may go against the grain of this forum, but it adds another perspective. Another option is to overboard with plasterboard and skim with modern plaster. Not very period but effective and the original celing will be preseved largely undamaged above! I mention this as I have been down the road of doing a total house restoration these last 5 years and I realise it is important to choose your battles wisely. For example I think restoring windows is a must, or at least getting them right for the house, otherwise the house looks terrible. Using lime mortar outside on stone or old brick is a must to prevent future damage. It is nice to have good floor finishes, and keep original featrues like built in cupboards etc, but I have given up with lime plastering especially on ceilings. Unless you are trying to make your property a completely historically correct for a personal challenge, or you have amazing cornicing or ceiling plasterwork to preserve, boarding and skimming a ceiling might be one of those few jobs that you'll be glad to offload to a tradesperson!

 

[paulc]

boarding and skim a ceiling might be one of those few jobs that you'll be glad to offload to a tradesperson!

Having boarded a ceiling myself, it is no fun struggling with 1800x900 sheets single handed on a step ladder. Wouldn't even consider 2.4mx1.2m sheets....

Next job on my list is the kitchen - This is currently a half & half mix of plasterboard and lime & lath ceiling. The whole lot is coming down and then plasterboard going up. This time, I'll be working off a scaffold tower and using a little helper. Will be skimming with a lime plaster after using a suitable primer.

 

[MikeG]

boarding and skim a ceiling might be one of those few jobs that you'll be glad to offload to a tradesperson!

Having boarded a ceiling myself, it is no fun struggling with 1800x900 sheets single handed on a step ladder. Wouldn't even consider 2.4mx1.2m sheets.......

There's where you went wrong.

Tacking a ceiling alone isn't easy, but it is do-able. You DON'T use a step ladder! You have to set up boards (usually on blocks) at exactly the right height so that when standing on them your head can support the plasterboard sheet tight against the ceiling. You will also need a "dead man".........a tee shaped prop which you pull into place to support the plasterboard in a second position (your head being the other). I pre-screw some screws prior to lifting the board so that I can quickly get a few fixings in without doing too much fiddling around.

The alternative is to hire a board lift. With these you just put the board on the lift platform and wind a handle. This will require a totally clear floor, but it does allow accurate location of the board, and is much easier on your head and neck (although less easy on your wallet).

 

[Anonymous]

My Sympathies on your ceiling, definitely worth having a go yourself, if all else fails you can then get a professional in to fix the problem...good luck!!

With regard to plasterboarding I found a really good technique on youtube, where basically you screw some screws half way into the wall just below where you will be putting the plaster board. You use the screws to hold the plaster board in position on one side and then simply screw the board to the joists. Very easy and saves a lot of money on board lifts etc. I've successfully boarded most of my bathroom using this technique and this has an apex ceiling rather than a flat one, good old Youtube !!

Unfortunately it has meant that I've now taken to leaving comments on all the chemical damp proofing videos which in turn has resulted in quite a lot of hate mail but there you go.

Paul.

 

[Flyfisher]

Unfortunately were welcomed by a big chuck of the ceiling resting on the floor as we walked in for the first time since our last viewing :roll: . I assume that as the house has sat unoccupied and damp for at least 6 months, resulting in the lime absorbing water and becoming heavy and weak. I've had a quick tap about around the rest of the ceiling and it all seems stable, however it does have a "marbled" effect with vein like cracks all over.

It's hard to guess why that patch of ceiling collapsed, though I wouldn't automatically assume it was because of damp causing it to become heavy and weak. I say that because we had a lath & plaster ceiling that was completely soaked during a pipe leak, so wet in fact that the ceiling paper peeled off of its own accord! However, the lime plaster stayed put, dried out without apparent harm and remains as solid as ever about eight years after the event.

Having said that, Given the circular nature of the fallen plaster, could there be, or have been, a long term water leak (from a pipe or roof) near the centre of the failed area?

As for repairs, be sure to ensure that the old plaster is fully removed from between the laths, otherwise the new plaster will not be able to push up between the laths and form the 'nibs' that provide the essential 'grip' on the laths.

Also check the nails securing the laths. Long term damp can cause the nails to rust away and fail, resulting in ceilings (or walls) to become detached from the underlying structure, even though the like plaster itself may still be in good condition. That doesn't look to be the case in the photo here but it's worth bearing in mind.

 

[Roger H]

[/quote]

Next job on my list is the kitchen - This is currently a half & half mix of plasterboard and lime & lath ceiling. The whole lot is coming down and then plasterboard going up. This time, I'll be working off a scaffold tower and using a little helper. Will be skimming with a lime plaster after using a suitable primer.

Hi Paul,

Not quite sure why you would use lime on a plasterboard ceiling? Do you think it is likley to adhere? It's not helping breathability on a ceiling, although it might act marginally as a humidity buffer. I'd be inclined either to replace the laths with new and do it in lime, or just gypsum skim if you are putting up modern plasterboard.

Best,

Roger

 

[paulc]

There's where you went wrong.

Tacking a ceiling alone isn't easy, but it is do-able. You DON'T use a step ladder! You have to set up boards (usually on blocks) at exactly the right height so that when standing on them your head can support the plasterboard sheet tight against the ceiling. You will also need a "dead man".........a tee shaped prop which you pull into place to support the plasterboard in a second position (your head being the other).

Screwed a couple of blocks to the joists so that the plasterboard would be held in place at one end, a deadman prop to hold the other end (or middle) up - Wasn't too bad for most of the boards, but would have been so much easier with a helping hand. Have now invested in a scaffold tower, so I won't have to struggle when in comes to doing work in the other rooms.

Not quite sure why you would use lime on a plasterboard ceiling? Do you think it is likley to adhere? It's not helping breathability on a ceiling, although it might act marginally as a humidity buffer. I'd be inclined either to replace the laths with new and do it in lime, or just gypsum skim if you are putting up modern plasterboard.

Half the kitchen is a 1970s extension, all the walls have been skimmed in gypsum (over gloss paint in some areas). The breathability of the walls has gone out of the window, and I need to add insulation to the extension - Will use Celotex/Kingspan as it provides a better U-value in the space I have available. As for "why lime", I want to use polished plaster throughout, so a skim of lime will provide a suitable key. I've done a couple of test panels primed with Febond Blue Grit and another with an acrylic primer with added sand - Both appear to be holding up well and the lime isn't flaking off. One could use Baumit DG27, but it is so expensive compared to some of the other primers on the market.

 

[Zebra]

You can use lime hemp plaster as a base coat. Breathable and strong, perhaps a little less authentic.

 

[MikeG]

How is a tower going to help? It will only get in the way.

 

[Damon]

Unfortunately were welcomed by a big chuck of the ceiling resting on the floor as we walked in for the first time since our last viewing :roll: . I assume that as the house has sat unoccupied and damp for at least 6 months, resulting in the lime absorbing water and becoming heavy and weak. I've had a quick tap about around the rest of the ceiling and it all seems stable, however it does have a "marbled" effect with vein like cracks all over.

It's hard to guess why that patch of ceiling collapsed, though I wouldn't automatically assume it was because of damp causing it to become heavy and weak. I say that because we had a lath & plaster ceiling that was completely soaked during a pipe leak, so wet in fact that the ceiling paper peeled off of its own accord! However, the lime plaster stayed put, dried out without apparent harm and remains as solid as ever about eight years after the event.

Having said that, Given the circular nature of the fallen plaster, could there be, or have been, a long term water leak (from a pipe or roof) near the centre of the failed area?

As for repairs, be sure to ensure that the old plaster is fully removed from between the laths, otherwise the new plaster will not be able to push up between the laths and form the 'nibs' that provide the essential 'grip' on the laths.

Also check the nails securing the laths. Long term damp can cause the nails to rust away and fail, resulting in ceilings (or walls) to become detached from the underlying structure, even though the like plaster itself may still be in good condition. That doesn't look to be the case in the photo here but it's worth bearing in mind.

Thanks for the replies everyone. I think I'll use a hair and lime putty mix to repair the ceiling. Ideally I'd like to keep it as close to original as possible and stay away from any gypsum based plaster where possible.

The house was so damp ALL of the wallpaper had taken itself off or partially off the wall. A lot of the wallpaper layers were stuck onto layers of artex style foam plastic wallpaper so there was no way it was going to breath. The 5 layers of carpet didn't help either...

We have since removed all the carpet plus the wallpaper whilst airing out the house and the humidity levels have dropped already. As to why that specific piece of plaster had failed I have no clue. There is no pipework above it (none in the main house anywhere near it) and there are no leaks I can see at all. The lath isn't damp and any plaster around the edge is the fallen section is dry to the touch also. Strange one!

Would you think a finishing lime wash/washes across the whole ceiling will help with any fine cracks in the remaining plaster?

Thanks once again for the replies. Informative as always

 

[Flyfisher]

Fair enough, it'll probably just remain a mystery then - there are usually at least a few with period properties. Perhaps the previous owner's removals firm dropped something heavy on the floor above :wink: At least it sounds like the rest of the plaster is sound, which is good news.

As for the fine cracks, lime wash is a good filler for small blemishes. An alternative is to use a good lining paper before painting. We've done this on a section of ceiling that was in poor condition because of historical rain ingress and it has stabilised the plaster but also followed the contours of the ceiling so that it matches the other sections of the ceiling, rather than being dead flat - though this may be less important if your ceiling is in good condition and is all in one section rather than divided up by beams.

 

[paulc]

Just to throw another option into the mixing pot...

If the laths and/or nails are rotten, you could fill the gap with woodwool boards - These can be fixed in place with screws then skimmed with lime plaster. Available in a variety of thicknesses from 15mm to 75mm (if you use the Savovit boards).

How is a tower going to help? It will only get in the way.

If you have high ceilings (mine are 2.7m, the stairwell even worse), the boards can be rested on the ends of the tower before finally lifting in to place. Once up, it is much quicker to scoot across the platform inserting fixing screws, scrim tape, or slapping on a bit of plaster. If nothing else, a lot safer than working off a step ladder.

 

[MikeG]

You didn't read what I wrote before?

You should NEVER work off a step ladder when doing a ceiling. At any stage, ever. You set up boards at shin height or thereabouts such that the ceiling is at your head height. There are people who do this for a living, and they do it the way they do it for very good reasons. Please re-read my previous post. There are only two viable options for doing a plasterboard ceiling, and neither of them include tower scaffolds or step ladders.

 

[Andys]

If plasterboarding a ceiling again, I would definitely try out a board lift. My only experience, even with a deadman was distressing due to not being a super-strength octopus - once the board's in the air you have to either get it fixed quickly or die trying.