Clay paint v Contract trade Emulsion

[michael]

I was astounded to find that as of January 2009 a 5lt tub of ‘off white’ Earthborn clay paint from my local supplier now costs £42.50. Almost double the cost of regular paints and emulsions. I have a large house and I don’t intend to take out another mortgage just to paint the interior.

If I was starting from scratch, I would opt to paint all the walls with limewash but unfortunately, I have inherited a multitude of bodged wall surfaces ranging from modern gypsum plaster to old lime plaster many of which are emulsioned. There are also some areas of new lime plaster which I applied myself to areas where the gypsum had failed. In some instances all of these surfaces can appear in one room.

Obviously, I want to achieve good adhesion to these varying surfaces and a consistency of colour and finish throughout, I also wanted to allow the new and old patches of lime plaster to breath, I figured therefore that clay paint would be the solution however the cost of this product would seem to make it very prohibitive when dealing with a large property.

I am looking therefore at alternative 'multi surface' paints that are more sensibly priced and I have been advised that Contract trade emulsion may be the answer - the cheap, very weak and wishy washy paint that is apparently very breathable.

I understand that this paint is applied to new gypsum plaster on new builds and its breathability allows the water to evaporate and the plaster it is covering to fully cure. Apparently it is also recommended by SPAB particularly in cases like mine.

I wondered if there was any difference between the various brands of Contract Trade Emulsion e.g. Leyland , Dulux etc. I understand that NBT Eco trade emulsion is pretty good (very breathable) but is it any different from the others?

I would be most interested in your views and comments

 

[Schoolmarm]

I used it in my bedroom, it took lots of coats to get any depth. If you have a lot to do you may need to bear that in mind.

 

[Flyfisher]

I'll be following this thread with interest as, although some while off yet, I'm going to face exactly the same problem. I've used F&B caesin distempter in a small part of the house but it was about the same price as (maybe a bit more than) the earth paints.

I suspect the problem is matching the breathability of the paint with the required/ideal breathability of the walls. Presumably, limewash on a lime-plastered/lime-mortar wall is going to be a good match but given that emulsion paint is, fundamentally, a suspension of water-repellant material, it must surely be 'not very' breathable when it dries out and leaves a water-repelling layer of paint on the walls. But perhaps it would be 'breathable enough'?

I can imagine that a very thin, wishy-washy emulsion paint might be 'more breathable' than a thicker one-coat emulsion, but it'll need multiple coats to give a good solid colour covering so will the end result be the same as a thicker one-coat emulsion - i.e. 'not very' breathable?

Or, is this 'trade' emulsion a fundamentally different sort of emulsion that confers extra-breathability. I doubt this, but it's only a guess. I've always thought the advantage of thinned emulsion was to 'seal' newly plastered surfaces before applying the colouring coat(s) and the cynic in me says that if 'trade' was significantly different, i.e. more breathable, then it would not be sold off cheap but would be packaged as a 'special' breathable paint with an appropriate premium.

In other words, I don't know the answers either, but would very much like to learn before I have to splash out on more very expensive paint.

 

[Schoolmarm]

I think the important difference might be the lack of acrylic in the trade emulsion.

 

[michael]

Good point schoolmarm

These are the websites for NBT. What do you think?

http://www.natural-building.co.uk/eco_paint.htm

http://www.natural-building.co.uk/PDF/Eco%20Paint/NBT_Eco_Emulsion_Paint.pdf

I think they cost about twenty somthing pounds for 5lt against forty someting pounds for the clay paints.

 

[Flyfisher]

Yes, good point about acrylic, but the paint on that first NBC link has "Vastly reduced TiO2 and Acrylic resins compared to standard trade emulsions", implying that even trade emulsions use acrylic. I guess we need some actual breathability specs to really compare the options.

Interesting article here: http://www.greensteps.co.uk/tmp/assets/1162572170890.doc
Especially the section "Health and Buildings" on page 10.

Minke has done some interesting work comparing the effects of different paints and finishes on the moisture vapour absorbance of a clay wall, and has also found that until you reach a very high resistivity, as in double boiled linseed oil (probably similar to epoxy resin resistance) the finishes on the walls make relatively little difference to the wall performance (Earth Construction Handbook by Gernot Minke WIT press 2000 pages 16 – 18 ).

 

[Cloudscape]

Interestingly (maybe) the stockists list on the NBT website includes Mike Wye and Ty-Mawr.

http://www.natural-building.co.uk/nbt_products_purchasing.htm

 

[michael]

Still looking at alternatives to clay paint
Dose anybody know anything about Silicone resin emulsion paints. I’ve just seen this website

http://www.srep.com/srep/en/die_initiative/faq/faq.jsp

Obviously it’s meant for exterior use but it seems to have all the breathable properties. Could it be used indoors? What’s the finish like? (Dose it come in matt) Is it affordable? and is it easy to obtain?

 

[Carol]

Try Potmolen in Warminster, Wilts They do a mail order service, I believe.

We have very mixed surfaces and were told always to use Trade matt but found it fairly awful stuff, needing lots of coats and regular repainting. When buying lime putty I got talking to the very knowledgeable staff at Potmolen and was recommended something called Amstel soft distemper which we have now used extensively. On walls it goes on well, covers beautifully and has that nice chalky finish I like. Best of all it is breathable and will safely adhere to the lime parts and the modern gypsum as well. The Amstel covers very well so I only need two coats making it reasonably economical, 5l cans were about £35, cheaper than clay and not much more than D**** or C****. Colour can be tinted to anything.

Don't know much about techy specs. but it is 'green' too apparently!

 

[Cloudscape]

If you're looking at silicon paints (about which I know nothing) there's a reference to them on the page you linked to above: http://www.natural-building.co.uk/eco_paint.htm

BaumitBayosan Silicon masonry Paint a highly breathable external masonry paint.

It wasn't easy to find a link in English, but...

http://www.baumit.com/en/main4/sub2/15368

 

[Penners]

Michael

I was in H*mebase today, and happened to spot a range of emulsion paints that I haven't seen before. It's called 'Ecolibrium' (made by Blackfriar) and they have some really lovely colours (IMO).

They claim that the paint is made with over 90% natural ingredients. Quite what the other <10% is, they don't specify!

I don't know whether that's of any interest.

 

[middi]

If the other 10% was non toxic the would have gladly advertised what it was. ( pullonium 5 ??)

 

[Cloudscape]

There's an Ecolibrium website:

http://www.ecolibriumpaints.com/SupportTool/News.aspx?aid=50

One assumes, if over 90% of the ingredients are 'natural' (some extremely toxic substances are 'natural' :? ), then the rest of the ingredients are 'unnatural'?

I can't find any info on breathability.

 

[Flyfisher]

Could emulsion paint be 90% water?

The natural-vs-unnatural issue can be amusing, as Cloudscape rightly points out. I recall reading somewhere that some 'E numbers' actually refer to perfectly naturally occuring substances.

 

[Penners]

There's a TV ad campaign running at the moment for Natural Mineral cosmetics. The implication being, presumably, that it's perfectly natural for women to slap minerals on their faces (as nature intended).

:roll:

 

[Jon Maine]

http://ecosorganicpaints.com/

Well worth a look too

 

[Flyfisher]

There's a TV ad campaign running at the moment for Natural Mineral cosmetics. The implication being, presumably, that it's perfectly natural for women to slap minerals on their faces (as nature intended).

Yep, those Elizabethan ladies knew a thing or two about natural cosmetics. Well, white lead is natural isn't it? :lol:

 

[MdB]

The natural-vs-unnatural issue can be amusing, as Cloudscape rightly points out. I recall reading somewhere that some 'E numbers' actually refer to perfectly naturally occuring substances.

A lot of you (including myself) have been putting E170 on to your walls. Don't go licking it though as it can cause confused behaviour, abdominal pain, weak muscles and kidney stones. Doesn't stop people putting it in biscuits, bread, cakes, ice cream, sweets, vitamin and other tablets and toothpaste though.

E252 is used to make gunpowder and in the preservation of meat products, such as, cured meats, bacon, ham, tongue, sausages, smoked frankfurters, pressed and tinned meats such as corned beef and some Dutch cheeses. No side effects unless consumed together with a burnt sausage covered in a sulfur sauce whilst smoking...

E290 is put into drinks and causes belching, asphyxiation and global warming.

E901 is good for making candles and chewing gum. No known side effects.

All can be considered natural (there are many others) for most peoples definition of natural. The E of E numbers just means it is approved for food use as an additive.

(E170 is carbonated lime / chalk, E252 is saltpeter, E290 is CO2 and E901 is bees wax)

 

[Penners]

E170 ...can cause confused behaviour

E290 is put into drinks and causes belching...

Mrs P is greatly indebted to you, MdB. At least she now has an explanation for her husband's little ways.

 

[michael]

Thanks everybody. At the moment , it’s a toss up between Carols suggestion of Potmolen Amstel soft distemper and NBT eco trade emulsion which they claim has good opacity (spelling?) Just out of interest, what’s the average price for a five Ltr can of coloured Du**x emulsion these days? I was told that it’s about £38.00. If so then £42.00 for 5Ltr of clay paint isn’t so bad.