Contract (Trade) Emulsion vs Limewash

[Flyfisher]

Am I correct in thinking that ‘contract’ or ‘trade’ matt emulsion has no vinyl content and is therefore more breathable than ‘normal’ emulsion paints? And if so, how does it compare with limewash in this respect?

I know contract emulsion is typically used as a mist coat on recently plastered walls and ceilings, for which I understand increased breathability would be an advantage over a vinyl emulsion while the plaster might still be fully drying out.

My reason for asking is that I’m converting part of our outbuildings into a new workshop. The walls are a mixture of bare brick, chalk and modern block and I’m thinking it would be nice to smarten them a bit with a lick of paint. They are mostly solid walls with no DPC so probably a little damp but it’s an outbuilding so no big deal, except I don’t really want any ‘plastic’ paint to start peeling after a few years.

I’m thinking of using a contract Matt emulsion as it will be possible to use a roller and just two coats rather than brush on four coats of limewash and therefore much faster and easier.

 

[steveb]

No idea on vinyl content or not but I would use clay paint - may get also away with one coat although more pricey than contract matt but should at least tolerate the damp

 

[MatthewC]

No idea on vinyl content or not but I would use clay paint - may get also away with one coat although more pricey than contract matt but should at least tolerate the damp

Seconded - and clay paint is best rolled as well!

 

[paulc]

Am I correct in thinking that ‘contract’ or ‘trade’ matt emulsion has no vinyl content

Just had a quick look at the MSDS sheets for a couple of trade emulsions. They all state "vinyl" in the product description.

 

[livias]

I would use limewash. Who says you need four coats? Two is plenty for a shed, presumably you are not looking for perfection and you can always add more later if you fancy. Four is generally specified cos it is a sacrificial layer over lime plaster, there is a scaffold in position and it will be easy to do now but a pig later

Limewash is cheap as chips too

 

[Flyfisher]

Am I correct in thinking that ‘contract’ or ‘trade’ matt emulsion has no vinyl content

Just had a quick look at the MSDS sheets for a couple of trade emulsions. They all state "vinyl" in the product description.

I’m beginning to think there’s a difference between ‘trade’ and ‘contract’, though I doubt there is a formal definition - a bit like ‘breathable’ really. I’ve seen some ‘trade’ emulsions labelled as vinyl (stressing durability I suppose) but never for a ‘contract’ emulsion, hence my uncertainty. The emulsion I’m thinking of using is this one: https://www.johnstonestrade.com/product/jonmat-premium-contract-matt. Its data sheet makes no mention of vinyl and stresses its suitability for new plaster.

Hmm.

 

[Flyfisher]

I would use limewash. Who says you need four coats? Two is plenty for a shed, presumably you are not looking for perfection and you can always add more later if you fancy. Four is generally specified cos it is a sacrificial layer over lime plaster, there is a scaffold in position and it will be easy to do now but a pig later

Limewash is cheap as chips too

You could be right about two coats being sufficient. I was thinking four because that’s what I’ve used on the house (though that’s exterior so a somewhat different case) and because of the differing materials covering differently, so possibly needing several coats to get a uniform finish. But yes, it is only a shed.

I wasn’t going to bother painting the walls at all but after using ‘garage paint’ on the concrete floor it looks so smart that the walls now look very tatty, plus some fresh white walls will brighten things up as it has no windows, only a large roller door. TBH, what started as a ‘quick and dirty’ reorganisation of my general workshop chaos is turning into something of a mini ‘project’. My heart says limewash but time and not wishing to splash limewash all over the place is making me think about alternatives.

As for clay paint, I’m a big fan of the stuff and have used it in the house, but I think it’s a bit overkill for a rough old outbuilding. Also, the new workshop is quite large so claypaint would be quite expensive.

Double hmm.

 

[TheForge]

How about casein distemper? Fully breathable and won’t rub as much as soft distemper. Covers well in a couple of coats with a brush with no splashing or mess of limewash.

 

[Flyfisher]

Yes, I've also used that on some walls in our house and you're right about coverage and ease of application. I had discounted it for the same reasons as clay paint, though I'm sure it would do the job.

I've since found this interesting article, which suggests that contract emulsion might not be purist but is a good modern alternative in terms of breathability: https://traditionalpainter.com/distemper

Also, this interesting article on the 'problem with distemper' which suggests that modern 'oil-bound' (including caesin) distempers are not really true distempers in the traditional sense because their harder-wearing characteristics come at the cost of reduced breathability to the point that their are little different to 'contract' emulsion paints: http://patrickbaty.co.uk/2009/05/10/the-problem-with-distemper/

Anyway, I resolved my initial dilemma this afternoon, which was to paint one section of wall, on which I'm going to fix some shelves, with contract matt emulsion. A mist coat first and the second full coat applied after four hours. It will be fully dry tomorrow and ready for fixing the shelves, which will allow me to continue the grand-tidy-up, so all is good (if those articles are to be believed) . . . except that slightly nagging feeling that, in the words of the great bluesman Robert Johnson, I've been down to the crossroads and sold my soul to the devil :shock:

 

[paulc]

I’m beginning to think there’s a difference between ‘trade’ and ‘contract’, though I doubt there is a formal definition

Dug around a little more, and some places (i.e. the Screwfix forum) are saying that contract emulsion doesn't contain vinyl, whilst other places suggest it does. The datasheets don't really provide any hard information, so perhaps the only place that could say wold be technical support at the manufacturers. I'm inclined to suspect that both "trade" and "contract" contain vinyl (or an acrylic) as they both use similar biocides.

 

[Me!]

The Leyland Trade range includes a Vinyl Matt -
http://www.leylandtrade.com/products/product-detail/vinyl-matt.aspx
and a Contract Matt -
http://www.leylandtrade.com/products/product-detail/contract-matt.aspx

I have assumed that because they make both and the fact that the first says it is vinyl and the second doesn't, to mean that the Contract Matt does not contain vinyl.

Personally I have always found any vinyl matt will still have a slight sheen to its surface when dry, but I can confirm that Leyland Contract Matt does not. It is really very matt, like claypaint or limewash.