In my experience as a plasterer I would have to agree that finer sharp sand works better. I've now done an entire room, walls and ceiling with an earth-lime-hay mortar. I've experimented with different loams, different ratios, different fibers, different types of sand and what I can say with much confidence is that there are two things that cause shrinkage cracking: 1. too much clay and not enough sand 2. too coarse sand Much to my surprise, and very much by (happy accident) I found myself one day stuck with the "wrong" type of sand but I really wanted to get a wall done. So I said screw it, and just used this finer sand. And to my surprise it was a pleasure to apply, it floated MUCH easier and after drying there were no cracks. NO cracks and in some places the plaster was up to 8 cm thick. Ever since, I've been using the finer sand to mix with loam. A pleasure to work with and honestly, really not that dangerous. I've had some of my lime-earth mortar in my eyes on many occasions and honestly, I've never even used water to rinse it out as I find that it doesn't really burn. I figure there's not enough lime in the mix. And I've had NHL in my eye before and that was a bloody nightmare. Red eye for two weeks! Of course I'm not advising anyone to not treat earth lime mortar with respect, but then again, in my experience it's not really super dangerous. I can plaster for days and weeks without gloves and my hands are fine. Every now and then, once or twice a week I just apply a fat hand creme and that's it.
I hear so many people speak about trials, tests and studies carried out on NHL's, but can never find them online. Can anyone please link me to these reports?
I have watched so many videos on lime mortar for repointing old buildings. My terrace in york has been repointed in cement. The brickwork is getting ruined. What sands should I use in a mix. Washed, unwashed, fine sharp, course sharp. Colour? I am going to have to tackle the job myself. Will start on garden walls to get some practice in. I have ordered your book . Have decided that hot lime is the way to go not NHL as I have been recommended. Pozzalan or not. Any advice please.
Hi Nigel you mentioned chimneys. I’ve got a late Victorian house with quite a high chimney stack consisting of red facing bricks capped off with 4 course of blue engineering bricks. I can tell a lot of the original mortar wants replacing and some of the brick faces have blown. Given how exposed it is would repointing with a hot mix be appropriate? Many thanks.
if the original mortar is earth/earth-lime or lime mortar then you can repoint with a very rich lime mortar (1:1 ratio or even pure lime with fibre added). The intention is to create a sacrificial layer with high capillary action which both help keeps water from getting into the chimney but also helps to dry it out much quicker if a little water does get in.
@@vdsw9166 Thanks. It’s a strange house in the sense that it seems to have been constructed with different mortars. Some of the internal walls I’m pretty sure are earth lime but the mortar on the external skin could well have an element of Portland cement in it. In Nigel’s book it has a similar style/era house which he says would have been 1:2:9 cement-lime mortar. I know like-for-like is supposed to be the done thing but wondered if a hot mixed lime would be better than cement-lime even if that was what it was built with originally…
@@2BeefHair I personally do not know what the resulting pore structure of a cement-lime mortar would be. I would assume that a pure, hot mixed lime would get you a mortar with an ideal pore structure and maximum capillary action. But I can't say that for sure. Hopefully you can get a hold of Nigel or perhaps try David Wiggins. He's made some videos about this subject and they're on Nigel's channel here. Good luck!
Such powerful information ( and so "many" subscribers ). I'am from Russia I bow my head Sir. Thank you very much!
Great!
Thanks a lot!
Best regards from Russia!
Someone get this man a lavalier mic
In my experience as a plasterer I would have to agree that finer sharp sand works better. I've now done an entire room, walls and ceiling with an earth-lime-hay mortar. I've experimented with different loams, different ratios, different fibers, different types of sand and what I can say with much confidence is that there are two things that cause shrinkage cracking:
1. too much clay and not enough sand
2. too coarse sand
Much to my surprise, and very much by (happy accident) I found myself one day stuck with the "wrong" type of sand but I really wanted to get a wall done. So I said screw it, and just used this finer sand. And to my surprise it was a pleasure to apply, it floated MUCH easier and after drying there were no cracks. NO cracks and in some places the plaster was up to 8 cm thick.
Ever since, I've been using the finer sand to mix with loam. A pleasure to work with and honestly, really not that dangerous. I've had some of my lime-earth mortar in my eyes on many occasions and honestly, I've never even used water to rinse it out as I find that it doesn't really burn. I figure there's not enough lime in the mix. And I've had NHL in my eye before and that was a bloody nightmare. Red eye for two weeks!
Of course I'm not advising anyone to not treat earth lime mortar with respect, but then again, in my experience it's not really super dangerous. I can plaster for days and weeks without gloves and my hands are fine. Every now and then, once or twice a week I just apply a fat hand creme and that's it.
I hear so many people speak about trials, tests and studies carried out on NHL's, but can never find them online. Can anyone please link me to these reports?
Love listening to people in the uk using centigrade, litres, millimetres etc.
Is this a reupload, or did I watch it on another channel a couple years ago?
I have watched so many videos on lime mortar for repointing old buildings. My terrace in york has been repointed in cement. The brickwork is getting ruined.
What sands should I use in a mix. Washed, unwashed, fine sharp, course sharp. Colour?
I am going to have to tackle the job myself. Will start on garden walls to get some practice in.
I have ordered your book . Have decided that hot lime is the way to go not NHL as I have been recommended. Pozzalan or not.
Any advice please.
Hi Nigel you mentioned chimneys. I’ve got a late Victorian house with quite a high chimney stack consisting of red facing bricks capped off with 4 course of blue engineering bricks. I can tell a lot of the original mortar wants replacing and some of the brick faces have blown. Given how exposed it is would repointing with a hot mix be appropriate? Many thanks.
if the original mortar is earth/earth-lime or lime mortar then you can repoint with a very rich lime mortar (1:1 ratio or even pure lime with fibre added). The intention is to create a sacrificial layer with high capillary action which both help keeps water from getting into the chimney but also helps to dry it out much quicker if a little water does get in.
@@vdsw9166 Thanks. It’s a strange house in the sense that it seems to have been constructed with different mortars. Some of the internal walls I’m pretty sure are earth lime but the mortar on the external skin could well have an element of Portland cement in it. In Nigel’s book it has a similar style/era house which he says would have been 1:2:9 cement-lime mortar. I know like-for-like is supposed to be the done thing but wondered if a hot mixed lime would be better than cement-lime even if that was what it was built with originally…
@@2BeefHair I personally do not know what the resulting pore structure of a cement-lime mortar would be. I would assume that a pure, hot mixed lime would get you a mortar with an ideal pore structure and maximum capillary action. But I can't say that for sure. Hopefully you can get a hold of Nigel or perhaps try David Wiggins. He's made some videos about this subject and they're on Nigel's channel here. Good luck!
Hi again, what is "linsi oil "i don't understand the term in english ?
l'huile de lin
Linseed oil
@@KurtisHordmerci !!
Other question: what is "earth lime mortar "? Cause in france we have inded mortars with clay but ther's no lime in it ...
That's just earth mortar, not earth lime. There's a mix on one of these videos where Nigel shows it prior to adding quicklime