Lime Novices in need of help

[Crymac]

Hi guys! Really hoping someone’s able to help. We have an 1850’s Yorkshire stone terraced cottage.

We’ve recently had our internal lounge (facing external wall) and fireplace wall removed of gypsum. It’s about 20sqm. We were quoted £3k to have it plastered and the guy said we’d be better off doing it ourselves. Figuring we would not be able to do a good enough job, we went with a recommended plasterer who had used limelite before and was up for a challenge. The place we got the lime said they were happy to advise on application and the plasterer was happy to operate in this way.

We were really happy with the finish. Except the corners. The guy was also really disappointed. We were mostly disappointed with the guy advising as clearly the way corners should have been handled should have been explained from the base layer. The plasterer tried to make them a point, which clearly doesn’t work in lime. We’ve had bits chip off and it just doesn’t look good. We don’t need it 100% but we do need to do something.

We have started to test how we might fix this. We have sanded down a corner that will be covered by curtain, plan to lime plaster over then possibly sand back to make sure the wall and fix merge. Will this work?! Any better ideas?! There are only 2 corners that will actually be visible so we have plenty of practice opportunity. Just not quite sure if it’s just going to look like we slapped it on and it will just peel off?!

It’s a risk we look to save £2k of money we don’t have - so no regrets. But trying to find the best fix from this point. On the up side it appears our damp issues are resolved :mrgreen:

Pic 1 is the corner finish
Pic 2 is the sanded down corner
Pic 3 is one :shock: of the chips

So many thanks for any help or advice that can be offered!

 

[paulc]

From the lack of visible images, I'm guessing it is external corners that are the problem. There are several ways of doing corners so that they do not chip.

For sharp corners, beading is the "modern" way of doing them - Stainless steel works well with lime. galvanised rusts and stains the plaster. Alternatively, casting a corner bead in cement and fixing to the wall once cured has been used in the past. My 1920's house has quite a few areas where a preformed cement bead has been used (mainly around the chimney breasts).

For rounded corners, I believe the traditional way of doing it was to fix a length of dowel to the wall and plaster up to it - I'm sure the more experienced members will comment on this over the next few days.

 

[Gothichome]

Crymac, yes corner beads either in plaster or wood are the traditional way to do exterior corners, but they were applied before the wall was plastered as PaulC mentioned. A little late for that now. But you do have a much simpler option. Wooden corner guards were (are) a traditional way of of protecting corners after the fact.
Google this term you’ll get lots of images of what i’m Referring to.

https://www.google.ca/search?q=victorian+wooden+corner+beads&client=safari&hl=en-ca&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj5gNqZjrHgAhVPRKwKHa9BBc4Q_AUoAXoECAwQAQ&biw=1024&bih=698

You stain them up to match your woodwork. They Provide a classic look, and you won’t have to fuss with the repair of the chipped corners. You can still buy them brand new from a lot of mill shops that specialize in vintage woodwork or it’ll give you a good excuse to go antiquing.
Ron

 

[TheForge]

Did your plasterer use limelite in the end? Limelite is a cementious product, not lime plaster and not suitable for historic walls.

 

[Crymac]

Thanks all.

It’s actually internal. Not sure why the photos didn’t post- I’ll try again. There’s no beading so far so the top layer one sounds interesting. I’ll have a look, thank you. Would save a load of faff, especially for the corners under curtains.

No, steered clear from the limelite. It’s a fine finish lime putty /ultra fine silica sand at 1:1 ratio

Ps, photos aren’t posting cos they’re too large. Not quite sure how to reduce them :-/

 

[plasticpigeon]

It is not a good idea to sand lime plaster because itr has sand in it and the finish goes very rough. Wooden corner beads was traditional and stainless works well too as has been said. retrospectively it is tricky to make good in lime, and I can't see any problem in doing the corners in gypsum or touching up in gypsum as it is much easier to get a good finish and blend it in. So long as most of the wall is lime the difference won't be a big deal. In my house gypsum was used to make good around fireplaces as light sconces and the like when the house was built, but of course the gypsum back then was pure white plaster of paris which sets very quickly compared to modern pink plaster but it is the same basic stuff.

 

[Flyfisher]

The problem can also be completely avoided by plastering a gentle curve instead of trying to achieve a sharp-ish corner. I've done this around a number of windows and I actually prefer the result, though it's a personal preference of course.

I've trawled through my hard drive for a photo or two but can't find any, which I find hard to believe as I usually take millions of photos of any work (OK, I exaggerate, maybe only hundreds :wink: ) but I remember MikeG posting some photos of the rendering on his project. OK, those photos are exterior rendering but the basic principle applies. I think it looks really good.
Full thread here: https://www.periodproperty.co.uk/forum/viewtopic.php?t=16086&p=219549#p219533

The relevant photos:

 

[paulc]

Limelite is a cementious product, not lime plaster and not suitable for historic walls.

From the MSDS sheet: http://limeliteplaster.co.uk/wp-content/uploads/2017/11/SDS-03.01-Limelite-Plaster-Products-V6-August-2016.pdf

Limelite Products are cementitious based pre-blended and dry bagged. They generally comprise of variations in blends of ordinary and specialist cements, expanded perlite aggregate, limestone flour and hydrated lime, dried and graded fillers and fine aggregates and chemical modifiers to achieve specific properties.

Limelite Easy-Bond - is a controlled blend of sulphate resisting cement, ethylene/vinyl acetate re-dispersible co-polymer resin powder and water retention aids.

Limelite High Impact Finishing Plaster - is a controller blend of retarded hemi-hydrate gypsum plaster, hydrated lime and limestone flour with organic additives.

Hydrated Lime – Calcium dihydroxide 5-15%
Ordinary Portland Cement (OPC) 5-40%

So more of a cement render with added lime as opposed to a proper lime plaster.

 

[Crymac]

It appears my posts are very slow to upload. That house is beautiful. Yes we thought rounded corners would work better - and were thinking we could sand back and reapply the lime in a rounded fashion. Not sure if we’d manage to blend.

No sure about using the gypsum. The texture would be different and have heard bad things about it adhering. The top coat we have on is 1:1 lime putty /silica sand.

It’s over a lightweight insulating lime plaster. Would that be causing any of the issue?

Thanks

 

[Easrow]

The limelite I've been using is natural hydraulic lime (nhl 3.5) and contains no cement or additives so if it's that it should be fine. As for edges I've used wooden dowel from a diy store to reinstate the nice edges around my fire place but that needs doing before plastering. What I have found to tidy up corners is plasterboard jointing compound works great. I get a big tub of ready mixed and put it on as neat as possible but it's very easy to sand anyway and is reasonably strong. I use it for all my filling now as it's that good. In smaller areas like tou are doing it shouldn't cause a problem with breathability and even dries white. I've not had any issues yet after 3 years using it.

 

[plasticpigeon]

Crymac said that the plasterer had used limelite before and was up for a challenge and that the plastering was done in lime.

 

[Crymac]

Will look into the plasterboard jointing compound. Thank you.
The only limelite we found had Portland cement in it, so steered clear. We use a local lime manufacturer.

Would there be any way to get some dowling at this stage? We could dremmel in space - but presume that may weaken the wall/plaster

Really hoping my posts get approved soon- looks like I’m ignoring everyone!

Thanks all

 

[TheForge]

The limelite I've been using is natural hydraulic lime (nhl 3.5) and contains no cement or additives so if it's that it should be fine.

You’re right, I didn’t realise Tarmac have expanded the Limelite brand to include NHL now. Just make sure it is the NHL and not Renovating Plaster etc.

The dangers when a product range includes appropriate and non appropriate products within the same brand name.