Experimenting with limewash.

[FamilyWiggs]

The boys and I spent the weekend teaching ourselves some bricklaying - repairing the fallen down walls in the lambing shed (geese keep using this as a shortcut through to ravage the vegetable patch!).

I rather enjoyed it - but needless to say some of the work is "developmental" in quality. It looks rather rustic like the rest of the shed - particularly as we reused the bricks we dug up from where they fell out many years ago.

I'm thinking of limewashing the shed - partly to cover up my handiwork and partly to experiment prior to one day limewashing the exposed stonework of the house. There are layers and layers of limewash left in some places, so clearly this would have been the original finish.

Can I just check with the resident experts? I have a couple of 20kg bags of hydrated lime, which I don't think have gone off. Do I bung one of those in a dustbin of water and a bit of linseed oil and leave for a couple of days and then stir up? Is lime into water or water onto lime easier? Is a normal masonry paintbrush the way to go? Any particular safety precautions other than gloves and glasses?

Any other tips?

Thanks

 

[MdB]

I find that adding hydrate into a bucket of water and then topping up with water is best to keep the amount of air born powder produced to the minimum. I always wear a mask when mucking about with hydrate as it is nasty stuff to get into your lungs. Once turned into putty I'm a lot less careful with it but still wear gloves. Eyewear would sound a plan with limewash.

I remember reading that 50% lime putty to 50% water and mix well both before and during use is a good mix - I've not used it myself though was thinking about using it at one stage.

If you are going to add linseed oil - no more than 1% http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=8140

 

[Alex]

Please can I ask (another) stupid question ? What does the linseed oil do ?

Sorry to highjack your post FamilyWiggs

 

[robgil]

i have only ever used putty to make limewash , i wasnt aware that you could make it with nhl.
linseed oil , correct me if i am wrong, makes it a bit more binding/durable but a bit less porous.

 

[FamilyWiggs]

From my research (as opposed to experience) the linseed oil helps with binding to non-porous substrates such as cement render, and it also helps with watershedding which is useful for external applications like my lambing shed.

 

[worms]

From my research (as opposed to experience) the linseed oil helps with binding to non-porous substrates such as cement render, and it also helps with watershedding which is useful for external applications like my lambing shed.

And makes the building smell nice!

I've limewashed my house with home made limewash. For logistics and time reasons I make up small batches (builder's bucket) at a time from a bin of home-made putty. 50/50 water to putty (although it is hard to gauge how much putty there is in the bucket since it tends to be in big lumps with spaces between, so some batches will be more than 50%, others less) and then a splash of raw (feed-grade, VAT-free) linseed oil. I then apply it to the bits I can reach with a masonry brush and the bits I can't with a domestic mop on a long pole. I'ts a messy operation, so eye protection is a must (eye protection and mask when handling the hydrate). Gloves are probably advisable but I've never found them useful as I just end up with limewash up the inside of them.

It's all very amateur, but it works!

 

[jason.p]

We've used hydraulic (3.5) limewash on numerous occasions,esp where there's an issue with durability and exposure, but would use putty wherever possible otherwise. It's worth bearing in mind that as hydraulic sets under water, it ought to be fairly freshly made up as theoretically it will begin to go off as soon as it's mixed. The main problem with limewashing, as indeed with all limework, is preventing it drying too quickly before it has a chance to carbonate, so the stone or render must be damp to start with and drying controlled by frequent "mist" spraying and/or covering with hessian(kept damp) in extreme conditions. Ithink the aftercare is perhaps the most important part of the process, and often the least appreciated. We always like to use five coats on outside work.
I haven't any experience with adding Linseed oil and would need to be convinced that it doesn't affect "breathability".
On that subject, has anyone any experience or views on "acrylic" limewash. I imagine it does the same as Linseed oil, but I am instinctively suspicious of adding anything to a natural and time tested material as limewash!

 

[worms]

The main problem with limewashing, as indeed with all limework, is preventing it drying too quickly before it has a chance to carbonate, so the stone or render must be damp to start with and drying controlled by frequent "mist" spraying and/or covering with hessian(kept damp) in extreme conditions.

Plenty of cool damp days around here to limewash in! But I have always wondered how they managed to control drying in Greece and Spain on the old traditional buildings? I guess whitewashing might have been a winter task? And probably an annual task, too, so after a few years the layers would have built up to the point where a little flaking might not have mattered?

I imagine it does the same as Linseed oil, but I am instinctively suspicious of adding anything to a natural and time tested material as limewash!

Can't get much more natural and time-tested than Linseed!

 

[MdB]

http://en.wikipedia.org/wiki/Whitewash

"Linseed oil is sometimes added (typically 0.5-2%) to improve adhesion on difficult surfaces."

I've not heard of that one before...

 

[MdB]

Limewash on a different scale...
http://news.bbc.co.uk/1/hi/world/latin_america/10333304.stm