is lime plastering really necessary?

[Anonymous]

one of the things I've picked up from this forum is some discussion about lime v gypsum plaster.

Can I ask a question though please?

I'm in a 17C farmhouse and a lot of renovation was done here 15 years ago. Most rooms were plastered but the bedrooms were papered in thick anaglypta. Under the paper in the bedroom I'm decorating I found patches of relatively new gymsum plaster within overall old lime plaster. This makes me think the 15 year old plastering was likely gypsum throughout the house.

The bedroom now needs skim plastering to even up a real patchwork of mends over the years. I think I've read here that one should lime plaster over lime plaster on old houses to let the stones breathe and hence prevent damp problems. My question is though - if all the rest of the house was gypsum plastered 15 years ago and it's OK (ie no damp), can't I just gypsum plaster this bedroom?

or have I missed something?

Caroline (on steep learning curve..)

 

[Anonymous]

You will reduce both flexibility and breathability of the wall.

It cant be recommended. It does not necessarily mean it will guarantee problems in the short or the medium term but almost certainly in the long term.

Lime also has antiseptic qualities but simply looks better long term than gypsum.

 

[Anonymous]

You are very lucky if you haven't got cracks everywhere! Our place was 'done over' in 1979 and the gypsum skim is cracked badly in all rooms. We are gradually picking out the worst and repairing with a lime filler which moves flexibly with the house. A long job!

 

[Anonymous]

Yep I agree, gypsum plaster is cracked everywhare and was done in about 1991 in my house. Every surface was swirly artexed to cover up the cracks. Henous!!

We are hacking off all cement/gypsum externally and internally (room by room). Dirty job but still satisfying.

 

[Anonymous]

and me.................. exactly the same, gypsum, artex, cracks through artex......

Though yesterday I actually found some lime plaster (only about 2' x 1') underneath some gypum, painted a nice cornflower blue, probably why they then painted it in a nice bright blue gloss....

Graham

 

[Anonymous]

Yup - we have the same in the kitchen - lime then a skim then gloss paint under emulsion. Much of it loose and cracking.

The bathroom is going the same way.

It MAY be that the modern method of putting Unibond may help adhesion but I doubt it - not when the house moves - and putting a layer of something not too breathable possibly isn't a great idea either.

 

[Anonymous]

what is all this gloss paint on walls about?? did they not read the tin??

got a lime plasterer coming later to look at the room.. it wasn't easy to find one -I am considering a new career..

 

[Anonymous]

Gloss used to be popular in kitchens and bathrooms a few decades ago.

Lime plastering courses - see SPAB.


http://www.spab.org.uk

 

[Anonymous]

Oooo...
Sounds like I'm in trouble... Just found this amassing forum with all this knowledge. I have just bought my first Victorian flat and for me it's a new world, I'm used to Swedish wooden houses.

Anyhow, I have just ripped down 100 years of wallpaper (interesting to see how the design have changed) to the plaster, the wall behind was in a remarkable good condition.

"Just" a few cracks and holes, in the end though it ends up to be quite a lot of spots of improvements...
I popped down to the local DIY shop and bought a "All purpose filler", my only concern was that I wanted it to be easy to sand.

After reading this freed it sounds like lime plastering is the right way to go. Is that correct interpreted?

When I have decided to do with the loft I will be back with some tricky questions ?

regards
hakan

 

[Anonymous]

Oooo...
Sounds like I'm in trouble... Just found this amassing forum with all this knowledge. I have just bought my first Victorian flat and for me it's a new world, I'm used to Swedish wooden houses.

Anyhow, I have just ripped down 100 years of wallpaper (interesting to see how the design have changed) to the plaster, the wall behind was in a remarkable good condition.

"Just" a few cracks and holes, in the end though it ends up to be quite a lot of spots of improvements...
I popped down to the local DIY shop and bought a "All purpose filler", my only concern was that I wanted it to be easy to sand.

After reading this freed it sounds like lime plastering is the right way to go. Is that correct interpreted?

When I have decided to do with the loft I will be back with some tricky questions ?

regards
hakan

 

[Anonymous]

Well - for small cracks and holes an all-purpose filler is OK - but for anything larger proper repair is better, using the right material - lime!

 

[Anonymous]

same here!

ours was all replastered in the 60s then again in the late 80s. cracks all over the place! areas which were skimmed over lime have the skim lifting off the lime plaster underneath - the skim has cracks, but the lime doesn't.

 

[monkey writer]

Yep, my kitchen walls, I have discovered, are also covered in gloss paint. Several thick layers of the stuff, the top layer of which seems to be a layer of shiny plastic film... Anyway, over the top of this was various fillers, and several layers of wallpaper.

Can anyone recommend a good way to get this gloss paint off? Underneath it, the walls are a real mess, so I am (horror) considering just taking it off the external walls and leaving it on the internal walls as they aren't damp and it'll be a whole load less hassle.

What is the easiest lime product to use to skim the walls flat again? What should I use to fill the lumps where the plaster has come away back to the brick?

Where the lime plaster is lose from the bricks underneath, but still fairly solid, should I pull it off or fill around it?

Would love some answers; this is a very steep learning curve! Thanks!

 

[plumbers mate]

>>Anyhow, I have just ripped down 100 years of wallpaper (interesting to see how the design have changed) to the plaster, the wall behind was in a remarkable good condition.

Oh what a shame that the wallpaper has gone - did you photograph the oldest layers before removing them?

 

[Gervase]

Gloss paint is an absolute pig to remove, I'm afraid. If the plaster beneath is sound, then use a poultice stripper like Klingstrip, but you'll have a lot of mess when it comes to washing it off.

If the plaster beneath is blown and coming away from the wall anyway, you might as well take the bloomin' lot off and start again.

If you do go back to basics, then you can get away with two coat plaster - scratch coat of 3:1 sharp sand and lime putty with hair, put on to a max thickness of your thumb and rubbed down well with a wood float to close up cracks, following by a 2.5:1 seived sharp sand and lime top coat, put on no thicker than your little finger and scoured down with a wooden float followed by a polish using a wet brush and a steel float.

If it's in a kitchen and you're installing fitted units you'll be wanted plumb and square walls, so it's worth using dots and screeds and a feather-edge or a derby to get your coats nice and flat.

For details, have a look at Holmes and Wingate, Building with Lime; the best book in English on the subject.
If your French is OK, there's Bertoncello and Fouin Les Materiaux Naturels, which came out this spring, and is perhaps the best book of its kind around and available through Amazon in France. I can't recommend it highly enough.

 

[monkey writer]

oh man! I'm going to have to learn to plaster! I guess it's a good skill to know... I've always marvelled at how people can get walls so flat and square...

We're not really going for a fitted kitchen - we're going 50's style so mostly freestanding, except for (hopefully) one wall of English Rose units if we can find any cheap enough.

Thanks for the book suggestion. Much appreciated.

Under the gloss paint the original plaster has been filled in here and there and everywhere with a white powdery (though fairly solid) substance. What is this likely to be?

 

[BMcD]

When Gypsum finish is applied over the top of lime plaster it is akin to icing a cake in so far as you are covering a soft background with a hard shell and this is why cracking occurs. Each plaster coat should always be softer than the previous. Also where a gypsum or sand:cement backing plaster has been patched in next to lime plaster, where the hard and soft edges of the two plasters meet is a likely place for cracking. It is worth mentioning that gypsum based plasters and lime based plasters are not realy compatable although (for what ever reason) it is common practice for gypsum skims to be applied over lime work (with the liberal use of PVA as a bonding agent)

Gervase wrote:

If the plaster beneath is blown and coming away from the wall anyway, you might as well take the bloomin' lot off and start again.

I'll echo this sentiment but you may find that only the finish coat is loose in which case you will only need to apply a finish coat (you will know this if only a 2-3mm layer of plaster comes off leaving behind a firm sandy surface with swirly line scored into it).

Caroline wrote:

This makes me think the 15 year old plastering was likely gypsum throughout the house.

If it was refurbished 15years ago it will depend on the extent of refurbishment. It may be that it was only re-skimmed and so the background could still be original, all be it with patches of modern backing plasters here and there

 

[monkey writer]

Hello, I've been chipping away at the layers of gloss paint on our victorian terrace's kitchen walls and am testing out the klingstrip at the same time - it seems to work like magic so far.

However, the walls are generally quite a mess of various fillers and plasters and with my inexperience, I am having trouble identifying them and deciding what to do with them all.

The original lime plaster is fairly easy to recognise with the hairs sticking out, but there is also:

white powdery stuff (easily scratched but quite solid and firm) (this is under the gloss)
light grey powdery stuff (easily scratched but quite solid and firm)
Dark grey mortar type stuff (very hard, a recent addition)
Brown stuff (very hard, I suspect this was applied as a base for the pink stuff below)
Pink stuff (I guess modern plaster - it goes over the gloss)

Which of these are acceptable and can be left and which should I exterminate with extreme predjudice?

Thanks for all your help guys.

 

[Sue Wilkinson]

For details, have a look at Holmes and Wingate, Building with Lime; the best book in English on the subject.

It is a very good book, but a bit scary I should think for a new learner. My advise would be to read it, but not allow yourself to be put off by it. This is a book for the professional. You can get away with a bit less provided you follow the basic rules. I'd start with 2 coat work rather than 3. Its fine for a cottage or poorer town house.

On the point of fillers, I would avoid modern fillers if you ever intend to use a lime wash or distemper decorative finish in the future. The stuff just wont cover up. I saw an advert recently for a lime filler. Not used it, so can't vouch for it, but its worth investigating if you are about to fill lots of cracks in lime.

Chalk Hill Lime Products
Conservation Filler
For filling hairline cracks and stopping gaps. Will NOT shine through lime washes.

It claims to be made from lime putty and very fine silica sand. Will keep indefinatley if sealed. Available in 1 litre tubs by post.

Phone 01653 648112 for more info.

Sue

 

[BMcD]

white powdery stuff (easily scratched but quite solid and firm) (this is under the gloss)
light grey powdery stuff (easily scratched but quite solid and firm)
Dark grey mortar type stuff (very hard, a recent addition)
Brown stuff (very hard, I suspect this was applied as a base for the pink stuff below)
Pink stuff (I guess modern plaster - it goes over the gloss)

Which of these are acceptable and can be left and which should I exterminate with extreme predjudice?

Well it sounds like the bottom 3 are sand/cement and gypsum plasters whilst the top 2 could be lime based skim coats and if so and they are in good nick then keep the top 2 but get rid of bottom 3 then replaster with lsand/lime. See previous posts.