linseed oil in limewash????

[rog and gina]

We've finally started (lime) plastering the new wattle and daub panels, and have found info on web about using linseed oil in with the limewash. Apparently this should make it withstand the weather abit longer and hopefully only need re-doing once a year. Any comments, advice on doing this and what quantity would be greatly received,
Thanks

 

[Gervase]

It does help with weather protection, and also helps it stick better to less porous surfaces (like granite and similar stone).

The proportions I use are one 20-litre tub of putty to 40 litres of hot water and half a litre of linseed oil (ish - all proportions subject to variation depending on how thick the stuff looks and how I feel at the time!). Whizz the whole lot up with an electric paddle mixer - either one of those you stick in your electric drill or a chunky tailor-made one (which can also be used for plaster).

If you're going to put any colour in the wash, it's best to mix the whole lot up at once - for that I use 80 litre plastic dustbins.

Three coats of that will last a couple of years at least before it needs redoing.

If you want even more weather resistance (for a really exposed wall or chimney, maybe) you can use tallow. Ignore what the lime suppliers say about not being able to make a tallow wash without pitching it into the slaking trough as the putty is made - it's easy.

For an 80 litre bin you'll need about two kilos of tallow, and this needs to be grated. I stick it through a grater attachment on my Kitchenaid mixer, but you can do it by hand.
Then get theboiler cranked up to heat your domestic water as hot as you can. Mix two tubs of putty with two tubs of very hot water in the bin and then run off a third 20-litre tub full of near-boiling water. Start your paddle mixer and get the water churning as you add the grated tallow to the tub. This will melt almost immediately and form an emulsion with the water.
Pour this into the bin and carry on with the elextric mixer in the bin for another five minutes or so.

Result - hard-wearing tallow limewash.

 

[rog and gina]

wow!
Thanks for the very speedy response, we should be trying it this weekend if all goes well!
we are hoping to use stone dust with the mix, it gives a really soft creamy finish.
we will try to post some pics soon, now that we are getting somewhere near finished!

thanks again

p.s. any advice on how to stop the lime plaster cracking as it dries?

 

[Moreteyne]

Hi
Personally I would stay away from tallow if poss , as it does discolour in time due to bacterial growth. The linseed mix in the lime wash is a good idea though. I mixed Linseed in my limewash this year to make it more water resistant. As for cracking lime plaster , if you keep it moist wiith the odd spray , you should be ok. In ye oldy days they used to hang sack cloth away from the wall to create a mico climate that was nice and moist for nice slow drying. Remember also not to make you limewash to thick. I made this mistake the other year as it looked very wishy washy. The result looked great for approx 8 - 10 months , then lots flaked off due to it not carbinating correctly. My advise , keep the mix milky , very thin and use lots of coats instead. Good luck .

 

[Gervase]

The base coat will crack - it's almost meant to crack, but you should be aiming for small crazes rather than deep fissures. You get that by working the surface with a float and closing up the large cracks as it starts to go off. And, as Moretyne says, by keeping it moist with a plant mister spray and avoid direct heat and draughts.

Also, when you scratch the surface for the next coat you will reduce the risk of further cracking.

Wait until the first coat has gone at least 'green hard' - hard enough that you can't mark the surface with your fingertip but you can scratch it with your nail - before applying the next coat, or that will crack too (unless you're doing what's called 'coat and a half' work, which needs a lot more working over).

 

[rog and gina]

we had been told we wouldn't need to do two coats, mainly because thats how the original panels were finished. The cracks are very thin, do you think limewash will fill them in?

I think they might be drying out abit too fast because we still have quite afew of the panels to wattle and daub, so theres alot of air blowing through.

we might try to plaster when the daub has gone firm (normally a couple of days after applying it) rather than when its dry. Has anyone tried this before?

 

[Gervase]

If you've merely got surface crazing and you've used non-hydraulic lime, then limewash will seal any cracks and consolidate the surface perfectly.

 

[andrew gayton]

never use more than 1% raw linseed oil in any limewash mix.