Question about distemper
Anonymous asked:
Does a new lime plastered wall need to be coated with distemper to allow it to breath or do modern emulsions do the same ? is distemper applied in the same way as emulsion ?
Just to clarify, and avoid the misunderstandings:
Distemper bound with casein is based on chalk with a casein binder that makes the coating non-chalking and non reversible and not necessarily super breathable.
Soft distemper is based on chalk. It is chalking and reversible (ie can be washed off) is very porous, and is suitable for ornamental decoration.
Lime wash is based on lime. It is also chalking and porous and should not go on top of other coatings. It is suitable for interior and exterior lime plaster walls.
(Patrick Baty is the leading authority to grill on the technical nuances and differences)
Lime wash on interior lime plaster walls
The traditional finish on lime-based plaster is lime wash.
A recipe to mix your own limewash »
lime putty and water to a thin single cream consistency (I seem to remember 40kg lime made around 150lts lime wash), pigment if wanted, about 250ml boiled linseed oil (stops it rubbing off on your hand when dry).
I used a big 180lt barrel and a plaster mixer on the end of a drill, but then I was painting everything inside and out and wanted colour consistency.
Apply about 3 coats.
You find that it doesn’t look like you’ve done anything but wet the wall to start with. Then it dries and starts to go opaque. Wait till it is dry before re-coating.
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If you are near Bristol then Chards have everything you need – H J Chard & Sons, 1 Cole Road, Bristol, BS2 0UG. 0117 977 7681
How to apply limewash
Check out the video. The basic premise is to damp the wall first, apply a watery coat with a block brush, wait 20 minutes and then scrub the surface with a dry brush to even out the coat as well as possible. Leave 3-4 days and repeat.
Lime wash on exterior lime render
On ProjectBook, this article on exterior lime render explains the whole plastering process and the requirements for curing etc. Their recommended painting process is 4 coats of limewash with some added boiled linseed oil.
The silicate masonry paint they refer to in the article, I know of KEIM paints, which in simple terms combine with the substrate rather than lay as a coat on top of it.
Emulsion paint on lime plaster
You definitely want to avoid modern vinyl emulsion on lime plaster because lime plaster is breathable and vinyl emulsion would seal it and negate the breathability benefits of lime plaster.
Technically, cheapo contractors emulsion, Supermatt and the like are breathable, and are a suitable modern choice as a sealer / wash coat and finish on lime plaster (as well as on modern gypsum plaster surfaces).
So would I use Supermatt emulsion on new lime plaster? On exterior surfaces, definitely not, for reasons of durability. On interior work? I think some heritage-conscious plasterers and restoration folks would probably shoot me if they saw me use supermatt, but would they be right to be so disdainful? From a technical point of view, no, because it works. But if purists wanted the new lime plaster to be painted with lime wash, as in days of yore, then any emulsion would prevent the walls from ever being over-painted with lime-wash.
I have learnt from Patrick Baty, that not all modern paints are inappropriate in a traditional property, and it is good to realise that many traditional finishes also produced their own issues. Maintaining tradition is a good aim, but you have to realise that not everything old is good – tinkering with paint recipes didn’t start with the discovery of the oil industry. Craftsmen of olde always modified commonly used materials, trying to make them perform “better”, but as you can see from the introduction, overcoming some deficiencies in distemper, like chalking, result in frankenstein scrubbable impermeable hybrids that can create many vexing issues further down the road.
If you have any questions, post a question on our heritage decorating forum and we will do our best to help. TP decorators like Matt Evans of Welsh Heritage Decorating work with these products regularly.
Please share it on Twitter, Facebook, or print it out for reference. Thanks.
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19 comments to “Question about distemper”
[watch out!] Question about distemper – via #twitoaster https://traditionalpainter.com/distemper
RT @JGDecorator: @arugglesbrise Distemper can be as “breathable” as v.matt. Depends. Aftr researchin @paperspaints etc https://traditionalpainter.com/distemper
@acmasterpainter Andy, you are quite right. The matter of paints to use on lime plaster is a big problem, which most people get wrong.
@paperspaints is it fair to say that dead flat emulsions respect limeplaster “breathable”properties, but their sheen is mod not traditional
@acmasterpainter One coating for lime plaster is a trade emulsion although different jobs require different approaches.
Updated post addressing questions about painting over lime plaster, applying lime wash https://traditionalpainter.com/distemper expert input from @paperspaints
RT @acmasterpainter: updated post addressing questions about painting over lime plaster, applying lime wash https://traditionalpainter.com/distemper expert …
RT @acmasterpainter: updated post addressing questions about painting over lime plaster, applying lime wash https://traditionalpainter.com/distemper expert …
traditional distemper when being applied to new plaster, would have a base coat of clairecolle first. this would help reduce suction when applying the distemper. clairecolle is basicly traditional glue size. f&b reckon their distemper doesnt need it, but what do they know!
Limewash was not a particularly common interior paint in Scotland apart from farmhouse dairies and few other historical applications however distemper was.
We use quite a lot of distemper over old and new surfaces, lime and gypsum plaster. There are however a lot of modern paints formulated to go over lime plaster and we have been involved in the specifications for these. Many of the Italian paint manufacturers produce modern interior decorative paints suitable for use over lime plaster, there are also quite a number of UK eco manufacturers whose products are vapour permeable….whilst I love traditional paints there is nothing to stop someone with a listed home having very modern slick and decorative finishes over their lime plaster/ lathe and plaster if their decorator is willing to do the research
Thanks for adding your perspective Cait. You raise a good point about “if their decorator is willing to do the research” The toughest jobs are following behind decorators who didn’t do the research!
Very interesting article and thread, thanks for posting.
There will be a short test tomorrow Charlie, just to check it all sunk in 🙂
I’m quite absorbent, and most of it sunk in.
Hi I think I maybe having some issues with distemper. Im renovating a 1960s house have sanded the walls back and have got a really smooth finish but as soon as I apply any type of paint I get certain areas that dont stick and bubble up. I have tried zinsser perma white as a base coat which is a little better but as Ive sanded the walls so smooth it seems a shame to except a bubbly finish. Is there anything I can scrub wall with or seal with prior to applying emulsion. Many thanks.
Over surfaces where you know there is distemper Classidur Classic is the renovators friend.
The other approach is to remove what is there and start again. I wrote a piece on preparing walls for repainting where we used artex to soften the coating before easily scraping the whole lot off back to the bare plaster.
Adding Owatrol’s E-B to the first coat of a water based paint on a suspect surface would also greatly increase the chances of good adhesion.
if you are going with a modern emulsion as a top coat and are not looking at a breathable coating just give it a coat of Alkali resisting Primer, open windows, let it dry, scratch up before applying emulsion, and away you go.
I’ve just painted my ceilings with limewash and two surfaces have reacted whilst drying. It looks like the lime has dried on the surface and can be wiped off using your hand ! I’m guessing the original surface coating is distemper ? So my question is what’s the best was to correct my issue ? Do I wash and scrap it all off ? Or do I apply distemper over the top ? My ceilings are lath and lime and my house was built in 1793 . Thanks
My experience of limewash is not huge but it sounds like it could be a couple of things:
It has dried to fast this leaving the ‘lime’ on the surface. Scrape off and damp the area down a bit more and re apply.
It may also be that the limewash needs to be mixed a bit more. Remix and again damp dowm the surface and reapply as above.
Limewashing on ceilings is a pretty messy process and it is difficult to do without half of it running down your arms or ending up on the floor! Have a look at mineral paint systems too – like Keim. Much easier to apply and it won’t run down your arms!!