Is there a case for using modern "plastic paints"

[michael]

It would appear from numerous comments on this forum that Lime wash is the only paint that should be used if the exterior of an historic building is to be decorated, however I understand that the great stucco frontages of buildings by Architects such as Robert Adams and John Nash, particularly those in London, were originally decorated with paint made from White lead and linseed oil which unfortunately is now effectively banned due to its toxicity and can only be used with special permission on Grade I and grade II* listed buildings.

I live in a 19th C Grade II Stucco fronted building which appears to have had a variety of “off white” paint finishes over the years. I’m sure you will agree that lime wash in this instance would be historically and visually inappropriate as lead based paint was probably the original finish.

As lead based paints are now effectively unavailable to me the only other option would appear to be the modern paint varieties such as micro porous silicate which I understand like lime wash, soaks into the structure to some degree or the film forming acrylic resins both of which are often referred to on this site as “nasty plastic paints”.

As I understand it, the silicate paints look all together too modern and inappropriate where as the acrylic resin paints are probably the closest match visually to the original white lead paints.

Any comments or suggestions would be very much appreciated.

 

[JMartin]

My knowledge of limewash is very limited to say the least but I was under the impression that this could be coloured to suit. I think it's Mike Wye who can mix a colour match for you...is that a better option?

If you do decide to go with a modern finish rather than limewash you should be very wary of the claims made by the manufacturers who just want your money and don't care if your property is damaged by it years into the future. I speak from the experience of spending an hour on the phone to a salesperson recently who conveniently ignored me when I asked about condensation...his answer was that we won't have penetrating damp again. :roll:

I don't know if anybody has an opinion of the Never Paint Again chap (he didn't get back to me) but on the website he says that he fixes old buildings with lime render and applies his finish to the top....I presume this is a marketing tactic to make old building owners think he cares about their structure rather than an educated solution to the problem.

 

[michael]

I’m not sure that lime wash will ever give that slight gloss sheen that the lead paints provide nor would it give the durability. Apparently the lead painted forth bridge lasted 110 years before it had to be redecorated.

In a building conservation .com article by Gareth Davies 1996 it concludes:

“Typically lime washes require maintenance every few years; film forming systems from 5 - 15 years; and silicate paint systems perform from 15 years and upwards. For historic buildings the need to provide the most durable long-term protection will often be the prime consideration, particularly where scaffolding will be required for maintenance. However a balance may need to be struck between the need for durability and the need to maintain historic integrity and, where lead paints were used, the character of an area”.

I think in my case, lime wash would be completely out of character with the original lead paint finish.

 

[biffvernon]

There's a big difference between the look of an oil paint finish and limewash. If you want to reproduce the look of a lead and linseed oil paint, then use a titanium dioxide and linseed oil paint. TiO2 is not toxic. Lead carbonate pigment is not quite such a bright white as TiO2 even when new and it becomes yellower as the lead reacts with sulphur pollution in the air. To lesson the impact of this change, off-white and cream paints were popular. A little yellow ochre (iron oxide) pigment was added. The same pigment produces the same effect in a TiO2 linseed paint. Add yellow ochre to tone down the 'brilliant white'.

One advantage of lead pigment is that it gives a slightly more flexible film, so is still used for special situations such as windmill sails. English Heritage give a licence for its use where appropriate, but for most building situations lead paint is not significantly better.

You can mix oil paint with water paint to form an emulsion so, depending on proportions, there is a continuum between oil paint and limewash. The basic ingredients of white pigments such as TiO2, lime and chalk and the mediums of oil and water can be mixed at will to produce various finishes of various durabilities.

For masonry painting, the silicate paints do seem offer significant advantages in durability and breathability over modern 'plastic' paints, and can of course be made in any colour you like.

The main disadvantage of TiO2 as a pigment is that it's production involves digging very large holes in places like Madagascar where once a forest grew. Our desire to make our local environment bright, white and shiny has bad consequences in foreign lands. It would never be allowed in Surrey but we don't really care about what we don't see.

 

[JMartin]

In a building conservation .com article by Gareth Davies 1996 it concludes:

“Typically lime washes require maintenance every few years; film forming systems from 5 - 15 years; and silicate paint systems perform from 15 years and upwards. For historic buildings the need to provide the most durable long-term protection will often be the prime consideration, particularly where scaffolding will be required for maintenance. However a balance may need to be struck between the need for durability and the need to maintain historic integrity and, where lead paints were used, the character of an area”.

Fair enough but I would rather paint my house every three years than have to deal with spalled bricks again. No matter how much I read about the breathability of silicate coverings I can't help but view them as no better than a plastic wrapper and the fact that the salesman wouldn't answer my query about condensation to me just adds weight to my reservations.

I can see your point Michael...you have a large surface to cover and you want to maintain the original look without the time-consuming maintenance but there has to be a better way for you to do this.

 

[biffvernon]

I think you will find that the Beeck mineral paints have nothing at all in common with a plastic wrapper.

 

[JMartin]

I was referring to commercial so called 'maintenance free' wall coatings which the manufacturers claim to be self cleaning, crack resistance, water resistant, stain resistant, and virtually maintenance free. They also claim that these are breathable and will cure the causes of penetrating damp.

When I read micro-porous silicate I presume the person is talking about these such coverings rather than the product you have linked to.

 

[michael]

Are TIO2 paints available off the shelf Biff?

JM , I’m not sure if breathability is the issue here. I always thought that the white lead paints provided a tough, durable, impenetrable skin to protect the cement stucco, which is in itself, pretty much unbreathable and therefore needs careful and regular inspection and maintenance to prevent cracking and the ingress of any water which would cause the stucco to blow.

Best bet surely is to give cement stucco a totally waterproof raincoat.

The ‘internal’ faces of these exterior stucco buildings are normally bare lime pointed brickwork covered with a lath plaster skin which stands proud of the brick by an inch or so. I guess the walls therefore, are able to breathe internally.

 

[Nigel Watts]

I would challenge your assertion that Nash terraces were "originally decorated with paint made from White lead and linseed oil".

White oil based paint would certainly have contained lead, but contemporary accounts suggest that the stucco would have been left unpainted (so that it resembled York stone) and the exterior woodwork grained in imitation oak - ie dark.

The Crown Estate's standard for painting their Nash terraces in cream gloss with white woodwork is admirable in that it preserves the intended illusion that they were grand palaces rather than individual terraces, but it is certainly not authentic.

If your stucco has had modern paint applied, lime based paints are not likely to adhere. As a compromise I used a modern emulsion in a darkish sandstone colour (F&B's String) on my 1840 stucco, with black woodwork:

 

[michael]

Biff, I notice that the Beeck products are silicate based. is there any link here with Tio2

 

[biffvernon]

Linseed oil paint is manufactured by Allback of Sweden and imported by Holkham Paints who sell it themselves and distribute to a smallhandfull of other retiailers such as Greenshop.

 

[biffvernon]

Biff, I notice that the Beeck products are silicate based. is there any link here with Tio2

If it's white, it's probably got TiO2 in it. It's the commonest white pigment and is used in a zillion products.

 

[Nigel Watts]

If you want authenticity, try some historical research into your house/street. I did this before painting my exterior:

http://www.fitzwalter.com/house/colours.htm

 

[michael]

Biff, the linseed oil paint websites you refer to all refer to painting woodwork. Would these be suitable for masonry?

 

[Nigel Watts]

I think you need to decide whether you want to achieve an authentic look (with or without authentic materials, but probably the latter), or use authentic materials to give an inauthentic appearance.

Using white linseed oil paint on 19th C stucco falls firmly into the second category, and the only rationale I can think of for it has to do with being environmetally freindly. Linseed oil production is friendly, but Titanium oxide mining is pretty unfreindly I believe.

Why not consider the first option?

 

[biffvernon]

Yes, I'd agree with Nigel.

Apart from the other arguements, using oil paint over the whole wall would be jolly expensive. I'd use linseed oil paint on the woodwork and probably a mineral paint from Beeck on the masonry. Take a good read of their technical literature.