Painting render

[Tc345]

Hello all,

Long time lurker and (very) occasional poster here. I am planning ahead regarding painting the front elevation of our house this summer. It is Grade II listed and in a conservation area so there are the usual things to consider there. At present the house has some very shabby limewash on top of a concrete ( ) render and I am planning to paint using a more long-lived but still breathable (for what it's worth on render) paint than limewash, silicate paint is the top candidate so far (any recommendations welcome).

However my question really relates to preparation, from PPUKers collective experience what sort of preparation would be required? Do I need to make sure that all of the limewash is removed before priming and painting or will it be sufficient to go over the area with a good stiff brush, or a wire brush, or wire wool or even just a good pressure washer (my brother just bought a petrol powered one )? It's a rather large surface area so i'd like to keep the preparation as simple as possible.

Thanks

 

[88v8]

As you say, over cement render breathability is irrelevant. Provided there's no damp in the wall that needs to escape.

I would be looking at Granital.
http://www.keimpaints.co.uk/products/external_paint_systems/granital/

Other than removing anything unsound, not aware of special prep. Perhaps select your paint then check with the manufacturer. I would beware of using random primers beneath what is going to be a fairly expensive product.

Ivor

 

[Penners]

select your paint then check with the manufacturer.

I agree with Ivor. Before you use any paint over limewash, I should ask the paint manufacturer whether there's any risk of a reaction between the two products. I would also paint a smallish test area - maybe half a square metre or so - and leave it a few weeks to make sure it all looks fine.

 

[Keith Bowman]

Wouldn't it be simpler (and probably cheaper) just to repaint with lime wash? Our local supplier sells a product called 'Pozilime' which seems to stick to any surface and can be made upto any colour you like.

 

[Tc345]

Thanks for the comments.

I'm reluctant to use limewash as I'm looking for something that has a bit more longevity, there is plenty of other work to be done on the house without reapplying limewash to the front every few years, which isnt a trivial undertaking given its size.

I'll have a chat with the Keim people and see what they say.