Lime putty limewash on lime render - it's so easy
Limewash - why would you use anything else?
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| Limewashed lime render below the window sill |
A few weekends ago, it rained, and two bags of leftover ready-mixed lime mortar got damp. So I decided to use them up to rebuild the render on the bottom foot around the back of the house and then to limewash. Scroll down if you want to see pictures of how it looked before.
How to make limewash from lime putty
To make the limewash, I used well-seasoned lime putty. Some people start with dry lime. We had some leftover lime putty buckets that must have been at least six years old. I'm under the impression that (like a serious tipple) the more 'matured' the putty is, the better.
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| A bucket of lime putty |
First, I mixed the neat putty 50/50 with water. Make sure you wear gloves and goggles for this - lime putty is caustic and will burn your skin (I speak from experience). The putty in the bucket looked like yoghurt and had the consistency of butter. To make the lime wash, I simply ladled some out into the little red container and added the same volume in water, then stirred it. Some people force it through a sieve (I didn't). You could add earth pigments at this stage, but I wanted to see how the shade of white came out first. Here's a video from Mike Wye on how to apply limewash.
How to paint with limewash
1) Make sure the substrate is really dampened down. Not with water sitting on it, but properly soaked in. The limewash mustn't dry too quickly. For this reason, it's also good to wait for an overcast day, not too hot, not sunny.
3) Paint! It feels a bit like smothering thin yoghurt onto your wall. It might look a bit opaque when it's going on, but the colour will become more solid when it sets.
4) Make sure the limewash doesn't dry out too quickly. If it does, it'll become powdery. You can carefully mist it with a sprayer to keep it damp.
How many coats of limewash should I put on?
Instructions I read were talking about three to eight coats. But I did two. Two! The limewash covered so exceptionally well, that I don't think it needed more. And if it does, the limewash will store almost indefinitely, so I can just slap another coat on next year.
What did it look like before?
If you remember, hacking off the cement render was one of the first things we did after moving in, to tackle the damp back wall. Here's a reminder of how it all looked during that time:
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| The side passage in 2010. You can see the old cement render on the right and straight ahead. |
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| Roping in the family to help with the big dig (thanks cousin!) |
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| Lowering the ground level |
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| Cement render hacked off - leaving damaged bricks behind |
Wishwosh - back to 2018. I haven't taken any pictures of the lime rendering. It was just too hilariously painful. I never had any training on how to lime render and found that using lime mortar resembles trying to build sandcastles for the first hour or so. But eventually, magically, the mortar will always stick. And overnight, everything starts to set and get strong.
I have a feeling I may not be mixing the mortar long enough in the first place, but that's another story. Also the ready-mix dry bagged stuff is a bit different to self-mixed mortar made with putty (we tried both). The surface also needs to be a little rough, which (as you can see from the photos above) wasn't much of a problem for us. The render did slip off more easily from one section of smooth brick, which we should have scored a little first. Suffice to say that the mortar did eventually stick and we now have a new rendered plinth where the damaged bricks were.
To give you an idea of the colour of the render, here's a picture of the chimney pots, that were set in the same ready-mixed lime mortar. Guess which year!:
