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Lime Wash Undercoat Sealer?


joidevie

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Hi again.. More help needed if possible, and I've begun a new thread carrying on from the 'breathable plaster' thread.

We've been patching up rooms in a 200 year old village house, stripping wallpaper etc etc. and have interior walls which we want to lime wash with pigmented.. There are as you'd expect a number of 'mixed' surfaces to cover (often on the same wall face ie where filler, plaster, lime render has been used on the same wall in different parts), and a couple of early coats here and there are revealing some 'staining', blotching' type issues.. See pic:

[IMG]http://i1195.photobucket.com/albums/aa381/azillio/limewash/limewash.jpg[/IMG]

Is there any obvious 'breathable' sealer type mix/affordable product that we can try to minimise/eliminate these problems? I realise that the high alkaline content and reacts strongly with many materials..

I have read PVA type products don't react well to alkaline (?) and are not 'breathable'.. Though I have read suggested a coat of 'silicone resin emulsion paint' (equivalent product/brand in France?) could be an idea? Or a few 'eco' type shops have very expensive 'sou couches'..

Can anyone help with some ideas? Pachapapa?  Théière? Anyone else?

Many thanks...
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hi ok

                 Keep pva well away , you could hot lime it first  ,  it`s the way we used to do the old stone  cow sheds.. I sieved and sprayed the chicken coop with it , but it goes on just as well with a 7oz brush

 [IMG]http://i83.photobucket.com/albums/j311/daveolive/chickens/PDR_0151.jpg[/IMG]

                                 Dave

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Hi ok

                           Hot lime   is  agricultural lime      " Chaux Agricol "    quick lime   mixed  with water  and painting it on as soon as the " Slaking  process has finished ......    note add the lime to the water   and stand back it will boil the water  stir when still hot sieve and paint on hot

                             Dave

 

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  • 3 months later...

[quote user="joidevie"]Though I have read suggested a coat of 'silicone resin emulsion paint' (equivalent product/brand in France?) could be an idea? Or a few 'eco' type shops have very expensive 'sou couches'..

Can anyone help with some ideas? Pachapapa?  Théière? Anyone else?


Many thanks...
[/quote]

Don't use silicon based anything if you ever want to apply any other kind of finish except cladding. [:-))]

The point of lime washing limestone is the material (lime) will bond to each other not just sit on top like a paint. What the reason for your patchy surface is could be a mystery, something in the original mortar mix (dung) or what ever. Have you tried bleaching the effected area?

Hydrofuge type coatings can protect and even allow the surface to breath ( most coatings are made up of tiny spheres so air can escape between the spheres, however a hydrofuge coating by its very nature repels water so any lime wash coating on top cannot bond with the substrate. You would therefore have to use paint to finish the wall but that would also seal the wall unless it was a microporous paint.

Can you use a darker shade of lime wash?

Hydrofuge coating

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That's true, PPP, I've used the microporous paints myself ... on wood; so is there a plasterwork equivalent? We have walls with different types of plaster finish and some react to paints causing it to flake or "craze". Presumably some sort of neutralising agent is required? I'll be interested to hear the replies. Also the wood paints are expensive, I can't imagine having to paint all the interior surfaces first. Also walls tend to have continually high damp content due to the lack of a damp-proof course (whereas wood eventually dries out); is sealing in the damp really a solution? 
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It's a bit of a minefield!

There is an artisan chap ('recommended' by Batiments de France) who here advocates the use of Sikalatex as a 10% 'undercoat' for limewash..

And a number of people actually add it to the limewash..

It's tempting to try, although our GF front wall had some damp issues which I've solved by removing the amiante boards the owners had put in the walls to head height (trapping lots of moisture) and the lino floor (on top of tomettes) - re-rendering in pure chalk/sand.. I certainly wouldn't want to use non breathable products on these sections, however the rest of the house may be possible as the damp is not present there..

Would CASEIN be an option as an 'undercoat' ??

Cheers again..

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[quote user="sid"]That's true, PPP, I've used the microporous paints myself ... on wood; so is there a plasterwork equivalent? We have walls with different types of plaster finish and some react to paints causing it to flake or "craze". Presumably some sort of neutralising agent is required? I'll be interested to hear the replies. Also the wood paints are expensive, I can't imagine having to paint all the interior surfaces first. Also walls tend to have continually high damp content due to the lack of a damp-proof course (whereas wood eventually dries out); is sealing in the damp really a solution? [/quote]

Similar in principle to lime, stops "liquid" water going in and allows "vapour" water to come out. Think small particles and surface tension.

I have all my main timbers, after cleaning and treatment ( mixture of white spirit and dissolved moth balls), protected with microporous paint.

The main timbers are oak and roughly shaped and a good 300 years old, good for another 200 years.

Those pretty coloured "log cabins" in Norway and the Basque region use these paints on young timber; in effect the rain wont go in but the water vapour will come out, particularly in summer, allowing the "green" timber to mature over a period of years. A gradual process allowing the timber to bed down snugly.

A lot of rural dwellings in Poitou Charente were built with green timber as can be seen from the "panne faitières". 

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