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chaux tips and tricks


Charley
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Hello everybody,

I am just about to start pointing the outside of my Charante house and looking at my neighbours excellent finish makes me quite nervous! Just wondered if any kind people could give some advice on getting that flat and smoothe look. I was also wondering if it is best to clean the stone faces before or after 'chauxing' and how to do this. I cant really use sand blasting because of the environment around me.

Thanks for reading,

Charley
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I haven't done the outside of the house, only the inside but I watched some pro's doing the outside of a house near me...

They covered virtually all of the wall with the chaux mix, just leaving the most sticky out bits uncovered then once it had started to dry, brushed away the surplus with a wire brush until they had the effect they wanted.  This means, of course, that if you have a 'bad bit', you can leave it covered!  Except if it looks daft

Of course, this is the style in this area.  I don't know what the style is near you.

I can't help about the cleaning.  I would have thought before.

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Thanks for the reply Alexis,

I have just had an attempt at pointing a small section on one of the old barns on my property and came across a few problems....

1.I mixed to the proportions that the bag of chaux I bought (35kg bag = 10-11 buckets of sand, so I did 1 bucket of sand and 3.5kg of chaux).

I found that this looks too gray- almost like concrete! Does that mean I add more chaux or sand, I think I need quite a creamy white finish. Also this bag of chaux was NHL 5, I read in a renovation book 3.5 is most common. Does this make a big difference?

2.The finish is quite rough at the moment (trowl lines etc). Does anyone know how to smoothe it down and when to do it?

3.I tried to make the chaux all flat and level but im finding this difficult to achieve. Is this just a learnt skill or is there a secret trick to it?

Thanks for reading again, any links or advice really welcome!!

Charley
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Try doing lots of samples of mixes on the floor let them dry because the colour will change as it dries.To get rid of the lines let it go off a bit then pass a damp brush over it(paint brush or similar)This site might help www.c-e-s-a.fr This is a job that the more you do the easier to get the mix and the finish right so start somewhere less important!!!
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My mix was 2.5:1  So basically five of sand to two of chaux of exactly the same container...when I was pointing the inside I used a glass as I used to get so bloody bored I didn't mix up much!  I would say that too grey it lacks chaux. 

The wire brush will take of the excess and then a wet brush sounds good but I haven't tried it.  Did you sift your sand?  That makes it a lot smoother.  I use very dry sand too.  I've got some here in a bucket I was planning on using but changed my mind.  Don't forget too that you can change the consistancy.  You can start off pretty stiff and then mix it more watery which should - or might - make it smoother as a sort of top coat.

I'm afraid that it is trial and error to begin with.

I don't know what my chaux was as I bought a sack from the builders merchants and it had just been 'filled'.

Don't forget too to wet the wall or it won't stick!

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From my humble experiences with pointing I found that a lime and sand mix was so difficult to use because the transfer from trowel to wall was tricky, you had to time the clean up just right because if it was too dry it didn't smooth out using a soft household brush, and if too moist it left a lime stain across the stones.

Then I was introduced to Procalit F  My life was transformed.  You can obtain it from Point P, it comes in 25kg bags and comes in various pre-mixed colours (I use Ton Pierre) so every mix is the same colour.  I mix up a third of a builders bucket at a time and apply with a trowel to the gaps only, allowing a little time for it to go off and smoothing it with the soft household brush.  The difference from the wall using lime and sand to the ones using Procalit is brilliant.  I think you will find that Procalit is lime based so allows the walls to breathe.

My experience is only with stone walls where the original mortar has turned to earth so cleaning was easy because I had seen locals using a power washer to pre-clean their joints so I did the same.  I used a sand and cement mortar to fill in all of the big holes first using a ram-rodding stick and plasterers hawk.

weedon

 

 

 

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Using a wire brush tends to leave the mark of the brush and if your sand is grainy will pull out the grains.Mind having said that this might be someones desired effect.As for the actual putting in of the mix ,because the stones and joints aren't the same size flatten different size copper pipe( 6,8,10mm) to put the mix in place.Like I said earlier its doing it and finding whats right way for you that brings the results.As weedon says there are lots of pret a l'emploi on the the market www.weber-broutin.fr is one of many
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We've been reading this discussion with interest, but again found the colouring difficult having tries different combinations.  We have been using a sand that is slightly reddish yellow.  We have seen some in a trailer which was a much paler yellow and would match our the work on our existing walls.  We'd appreciate it if anybody around Bergerac to Sarlat could tell us if they've managed to locate sand of this colour.
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We've been reading this discussion with interest, but again found the colouring difficult having tries different combinations.  We have been using a sand that is slightly reddish yellow.  We have seen some in a trailer which was a much paler yellow and would match our the work on our existing walls.  We'd appreciate it if anybody around Bergerac to Sarlat could tell us if they've managed to locate sand of this colour.
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ive done quite a lot and this allways works,bog standard chaux from builders,the sand gives it the colour so shop about different sand different finish,when you have the sand you want get enough for the whole job you might not match it again later.i use a trowel to put it on,a wire brush to take it off and a softer brush to take out the lines left by the wire brush,let the mix go very nearly dry before wire brushing thisfirst brush work is what gives you the finish you want,mix a full mixer full 3 sand 1 chaux exact do it in level bucket fulls and allways the same mix so the colour stays constant,by the time you get a full mix on the wall the first bit should be about ready to come off.
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Our builders merchant produced a colour chart for the sand. We chose the colour we wanted and as long as we always get the same colour we don't have a problem. Our stones are 'river stones' and as such are very varied in colour with loads of rose quartz. We wanted a beige pink colour as that was the original colour of the mud (but the mud was much deeper pink) and the colour we were advised to use has worked well inside - we have the huge main area of the main barn to do before we venture outside but should be experts by then (well I live in hope ).
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  • 2 weeks later...

Maybe I'm a bit late adding to this topic but would like to mention some of the tips I picked up from a neighbour who is a macon.

Mix is better loose than dry, it sticks much better. Try throwing the mix from your trowel into the joints rather than pressing it in, over a couple of square feet and then remove the excess ith the edge of the trowel. If you place a board or a piece of plastic sheet under where you are working you can recycle all of the mix that falls off (you will need to add extra water to it), The chaux is ready to brush when you can just press a fingernail into it, if you are getting wire brush marks it could be because the surface is not quite dry enough or you are being heavy handed. After wire brushing the excess you can "paint" over he chaux with a wet paintbrush. This will make the larger grains in the sand shine. finally, if you have to leave a part mix in your auge for any reason, add more water and keep it in the shade, it should then rework when you come back to it rather than going hard. 

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[quote]Maybe I'm a bit late adding to this topic but would like to mention some of the tips I picked up from a neighbour who is a macon. Mix is better loose than dry, it sticks much better. Try throwing the...[/quote]

"Mix is better loose than dry, it sticks much better. Try throwing the mix from your trowel into the joints rather than pressing it in, over a couple of square feet and then remove the excess ith the edge of the trowel. If you place a board or a piece of plastic sheet under where you are working you can recycle all of the mix that falls off (you will need to add extra water to it), The chaux is ready to brush when you can just press a fingernail into it, if you are getting wire brush marks it could be because the surface is not quite dry enough or you are being heavy handed. After wire brushing the excess you can "paint" over he chaux with a wet paintbrush. This will make the larger grains in the sand shine. finally, if you have to leave a part mix in your auge for any reason, add more water and keep it in the shade, it should then rework when you come back to it rather than going hard. "

Could  not agree  more .  In  our  area   we  use  sable  jaune . Buy a  large  quantity  as  this  will   keep the  right   quality  through out the  job  .  The  mix   we  use is   4 sand to  either  1 white cement  and 1 chaux natural  or   4 sand to  2 chaux natural . We  use  the   chaux- cement   mix    because  the  outside  stone is  shale ( better adhesion )  but on  most other stone    use  the  chaux only  mix . The  inside of the  house  the  stone  quality is  better  so the  chaux  only mix is  better . Remember  chaux  was  used  because  1 . cement  was  too expensive  in the 1800's  but 2.  lime cement  breaths  allowing the  clay  filled walls  to give up   moisture .  Do not   use  the  cement  mix  on both  sides of  the wall as you  will have a  damp  problem .   We  found a wet  runny mix  was  best , the   walls  soaked  up the  extra   moisture  very   quickly , allowing   the  smoothing  with either a wet  paint brush  or  for large  areas a soft broom  head . Start  from the  top and  work down  , that  way  you  do not spoil  the  work  you  have  already   done .

Good  luck

 

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Hi

my local builders merchant has sand in various clours : gris, jaune, blanc

They were happy to give me a bucket of each to test colours.

We tested various colour mixes before settling on 1.5 chaux, 2 blanc, 1 yellow. Our test used plastic cup measures, then leave to dry : it is best to write down each mix tested !

Peter

 

 

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I have found that when recycling the chaux that has dropped on your plastic (or whatever) its best to use this in any deeper holes or gaps and then cover with nice fresh chaux. Even if you clean your wall real well I have found you always get bits of dirt and dust mixed in, which may effect the colour a little.

Also my neighbour finally helped me out a bit and reminded me that you must apply plenty of pressure and get it right into the wall. It aint just a pretty finnish.

Charley
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