A few limewash questions

[pandora]

At last! I am in a position where I can almost start to think about the internal decor of my house. The whole house at the moment is being plastered with lime plaster, and the plan is to use limewash wherever possible. My husband is quite picky about colours, and due to time constraints (baby due in a week!) and the range of colours available we are looking at Farrow and Ball limewashes. I know there are cheaper limewashes out there but compared to the price of the rest of the work it is not too much and we just want to crack on.

Here are my questions;
How long after the finishing plaster coat can I start to apply limewash to it?
How far on fresh lime plaster will each 5l can of F&B limewash go?
Will I need to water it down?
What should I use on the walls in my bathroom instead of limewash, and how long should I leave the plaster before applying this?
Will I be able to get away with limewash in my kitchen (It's quite large with a high ceiling.)
What are everyone's top tips for making sure I get the limewash on so it doesn't go dusty and gives the best finish?

Many thanks.

 

[Gervase]

You can apply limewash within a couple of days of putting on the finish coat - it will actually adhere better to 'green' plaster/
In my experience F&B limewash is far too thick and needs to be diluted 1:1 with water to cover properly. That will give you 10 litres, but ideally limewash needs three thin coats, so 10 litres probably won't do more than one large room (and it's messy stuff - plenty of dust-sheets and covers will be needed).
Limewash is fine for kitchens, and perfect for ceilings, as there's no chance of it getting scuffed there.
To prevent dusting you can either mix casein with it (in the form of casein powder dissolved in hot water, or even as a quarter of a pint of skimmed milk in 10 litres) or linseed oil; about half a cupful in 10 litres.
Apply it thinly, keep it moist for a day or so while it carbonates, and then recoat after two or three days. As I said, you'll get the best results with three coats.
To make your expensive F&B limewash go further, why not make your own to do the first two coats - just get a bag of fresh slaked (hydrated) lime from your local builders' merchant and tip it into a plastic bin with 40 litres of water, stir it thoroughly to disperse it and leave it for a few days, then whisk it up.
The consistency should be that of milk or thin cream, and it goes on translucent before turning brilliant white as it carbonates.

 

[BMcD]

Sorry if I'm hijacking this thread but...

Gervase wrote:

To make your expensive F&B limewash go further, why not make your own to do the first two coats... ...and it goes on translucent before turning brilliant white as it carbonates

Would it be worth adding a pigment which matches the final coat to this to retain the depth of colour or will it not matter?

 

[NT]

> How long after the finishing plaster coat can I start to apply limewash to it?

I leave a day between coats indoors, and its fine. It will carbonate faster in than out because of higher temp & CO2 levels


> How far on fresh lime plaster will each 5l can of F&B limewash go?

I dont know, but I do find with limewash a good deal more volume gets used compared to eg emulsion. At £6 per 100kg it doesnt particularly matter.


> Will I need to water it down?

> What should I use on the walls in my bathroom instead of limewash,

limewash has mould discouraging properties, good for a bathroom. Not very good cleanability though.


> and how long should I leave the plaster before applying this?

The surface of lime plaster is effectively limewash.


> Will I be able to get away with limewash in my kitchen (It's quite large with a high ceiling.)

cleanability and not being scuffproof... I wouldnt, but havent tried.


> What are everyone's top tips for making sure I get the limewash on so it doesn't go dusty and gives the best finish?

I dont think method of application would affect dustiness any. It all turns to anything from pure chalk to mixed carbonates if normal contaminants are present.

Has anyone tried adding pozzolanic chemicals to limewash to make it set harder and last longer?


NT

 

[Gervase]

Would it be worth adding a pigment which matches the final coat to this to retain the depth of colour or will it not matter?

If you wanted a real depth of colour - or a very dark hue, I suppose it could help. I tend to use 'vanilla' limewash for undercoating ochres reds and blue, though.

Has anyone tried adding pozzolanic chemicals to limewash to make it set harder and last longer?

You can make 'limewash' from hydraulic lime, in which case you have lime paint, which is OK for exterior use. For interior use, I'd prefer an oil-bound distemper.
As for dustiness, both casein and - to a greater extent - linseed oil will reduce this.

 

[worms]

And remember the tip that someone posted here before about buying the linseed oil from the animal feed store: larger volumes and no VAT!

And while we are on the topic, can you remind us what sort of pigments from the art shop are best? When you say "vanilla" is that just the normal white lime-wash or what are you adding to the mix to tone down the brilliance?

 

[pandora]

Thanks very much for the tips everyone.

 

[andrew gayton]

gervase - half a cup of linseed oil to 10 litres of limewash is a bit much in my opinion; I work on the basis that oil should equate to no more than 1%.............

and

as for f+b limewash - £££££££££££ - make your own.

 

[MdB]

gervase - half a cup of linseed oil to 10 litres of limewash is a bit much in my opinion; I work on the basis that oil should equate to no more than 1%.............

half a cup = 0.125 litres so half a cup in 10 litres is only 1.25% only slightly more than you suggest.

 

[andrew gayton]

small cup!

 

[MdB]

small cup!

0.25 litres is the metric standard for cup sizes. If any of you are drinking tea out of cups other than 0.25 litres then expect a visit from the cup size inspectors who will slap you with a £50 fine. You can get around this legislation by drinking in a designated wrong size cup area which must have suitable warning signs prominently displayed at all entries and exits.

Americans of course have a cup size of 0.236588 litres.

 

[andrew gayton]

'fair cop.............

 

[pandora]

as for f+b limewash - £££££££££££ - make your own.

In an ideal world ....... :wink: I was all geared up to make my own then I applied for my LBC and 10 months of my 12 month project was eaten up by the ******* conservation officer. With a baby due in 10 days from now and a husband who has just got a pay rise I am making the best of my cash rich - time poor situation. I like some of the F&B colours and just don't have the time to experiment with pigments to get the shade I like.