Silicate Masonry Paint as substitue for Limewash?

[Nigel Watts]

The contractor I have just engaged to strip the paint from and repair my exterior Lime stucco has recommended this to repaint it with afterwards:

http://www.earthbornpaints.co.uk/silicate-masonry-paint.php

Should I agree?

 

[biffvernon]

It's a once only decision.

 

[Nigel Watts]

A technical specification drawn up for the restoration of stucco houses in St Peter's Square, Hammersmith by Hammersmith & Fulham Council, which looks like it was written by Nicola Ashurst, an acknowledged expert on the subject, states:

"REDECORATION

If a façade has been painted, the redecoration of the repaired render will depend on the nature of the existing paint layers which are to be retained. Ideally, all impervious layers should be removed and a breathable coating such as Keim mineral paint, Granital system, be applied in the agreed and researched colour.

Modern impervious paint systems which are intended to provide a waterproof coating to buildings should not be used as they will trap moisture behind them and cause deterioration of stucco. Paint finishes which alter the texture of the existing finish are also unacceptable."

The Earthborn masonry paint seems to be quite similar to the Keim Granital one.

 

[Flyfisher]

This article may help: http://www.buildingconservation.com/articles/vapour/vapour.htm

Limewash:
The rapid increases in pollution since the industrial revolution, especially acid rain, has lead to a very rapid degradation of external limewash facades. Firstly run marks are noticeable on such areas as sills, copings, etc, due to the acid reacting with the limewash and dissolving it. Then eventually the entire facade will be attacked and degraded. Limewash provides protection for the surface as a 'sacrificial' coating, in that it is destroyed more rapidly than the material below it. It also can help to consolidate friable limestone surfaces. Limewash is most suitable for smaller historic buildings which are rendered or constructed of limestone masonry, cob or wattle and daub, where there is a need to maintain the historic appearance and where it is accepted that regular maintenance will be required. In the short term at least it is also relatively economical.

Silicate paints:
As a highly porous protective coating, silicate paints offer a valuable alternative to a limewash, and can provide for much longer life expectancies. There are documented examples of such paint systems performing satisfactorily on lime based render facades in Germany, Switzerland and Norway for periods in excess of 100 years.


Some comparative information here: http://www.heritageltd.com/masonry%20table.pdf

 

[JoceAndChris]

Fascinating reading above! My gut feeling is to go for the silicate masonry paint Nigel! That's a completely inexpert view just based on reading - but it sounds ideal!
If you could minimise the need to scaffold over the years it would be better wouldn't it?
I haven't tried the Earthborn paints and would need to see a large test area first to understand the finish, depth of pigment, etc, before making a final decision.

 

[Feltwell]

Non-expert view, but I would tend towards a silicate paint given what's been said above. There's nothing wrong with using appropriate modern materials in my opinion - change does happen and we do need to accept that in some circumstances a new product will perform better than that which was used originally.

For Nigel's house, which is in an urban enviroment and I presume will require expensive scaffolding in order to get safe access to paint it, I would go with a longer lasting paint system than limewash if the breathability is there and the appearance looks right. For a small cob cottage in the country, which could be painted relatively quickly from a ladder, limewash remains probably the better option.

 

[Flyfisher]

There's nothing wrong with using appropriate modern materials in my opinion - change does happen and we do need to accept that in some circumstances a new product will perform better than that which was used originally.

Not forgetting that 'modern' and 'new' in this context means something dating back to the 1870s. :wink:

For Nigel's house, which is in an urban enviroment and I presume will require expensive scaffolding in order to get safe access to paint it, I would go with a longer lasting paint system than limewash if the breathability is there and the appearance looks right. For a small cob cottage in the country, which could be painted relatively quickly from a ladder, limewash remains probably the better option.

I understand the sentiment but why would limewash be the better option? Since there seems to be nothing bad to say about silicate paint apart, perhaps, for the initial cost, why choose a material that would need reapplying every few years compared with one that would need reapplying every few decades?

BTW, I'm not saying there isn't anything bad to say about silicate paint, just that I've not heard of anything bad and I've been interested in it for a couple of years now because I'm going to have to take the plunge myself in the next few years.

It's a once only decision.

I'm hoping so. It seems that silicate paint has a good chance of seeing me out. :lol:

 

[Feltwell]

For Nigel's house, which is in an urban enviroment and I presume will require expensive scaffolding in order to get safe access to paint it, I would go with a longer lasting paint system than limewash if the breathability is there and the appearance looks right. For a small cob cottage in the country, which could be painted relatively quickly from a ladder, limewash remains probably the better option.

I understand the sentiment but why would limewash be the better option? Since there seems to be nothing bad to say about silicate paint apart, perhaps, for the initial cost, why choose a material that would need reapplying every few years compared with one that would need reapplying every few decades?

Cost vs benefit, plus I love the look of coloured limewash on a house! "Benefit" is of course subjective, and the importance of cost is influenced by your wealth! Personally, if the house was relatively small and easy to decorate then I think I'd still limewash. Also, "Worn" limewash still looks good on a small "rustic" country cottage, but would just look tatty on a "posh" townhouse like Nigel's.

All personal opinion and too many quote marks.

 

[Schoolmarm]

My daughter had her tiny cottage rendered in lime and then harled. Then painted in the silicate stuff. It is gorgeous.

 

[Flyfisher]

That's good to hear 'marm; it's the sort of thing I'm thinking about (without the harling).

 

[Schoolmarm]

I will be using it too after seeing hers.

 

[JoceAndChris]

It sounds perfect! I'm very drawn to this too for when ours is done.

 

[Flyfisher]

Limewashing our place could be a bit like painting the Forth Bridge . . . . except that a more modern alternative looks as if it might have killed off that particular metaphor: http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-14789036. Looks like I'll have to follow suit, but with silicate paint.

 

[michael]

I may be wrong but I don’t think Earthborn actually produce their silicate masonry paint themselves. As I understand it, it’s produced by a company called ‘Volvox’ and it may even be imported from Germany, consequently it’s horrendously expensive. It’s only available in 10 Lt tins and is in excess of £100 per tin for the coloured varieties. In addition, I think they also recommend applying a purpose made primer before applying the paint. Again very expensive but a good solution if you can afford it and if you want a uniform looking breathable finish

 

[JoceAndChris]

Eek! And I thought Rose of Jericho expensive!