Like the "shorts" Izzy. A good extra to the main vids, explaining in more detail various techniques, in this case, lime mortar. Nice one, appreciate you taking the time to do this. 👍
Izzy, I work as a volunteer on the Buildings Team at the Chiltern Open Air Museum. The Museum saves condemned buildings from the Chilterns, takes them down and rebuilds them on site using traditional methods of construction. At the moment we are repointing the Toll House from High Wycombe with lime mortar. I’ve never done this before but have seen your videos which I have shared with my co-workers; we all use your work as a guide and it’s beginning to look amazing. Thanks so much.
Hiya mate, that's amazing what your doing, restoring old buildings! Really pleased that my video was able to help you and your co workers 🙂🙂 please send me some pictures of the project ☺️ All the best
You can find PPE in the description below. If you'd like me to make a How to video on a topic your interested in, let me know in the comments below 👇 Side note regarding the mixer. Andy, from Bricklayers world wide, mentioned in my previous video, that using a paddle mixer (used for plastering) is a great alternative to using the bell mixer 💪
Proper lime mortar for stone buildings is hot lime mortar or lime putty. Lime powder or kibble ( calcium oxide) made from limestone rock ( calcium carbonate) during slacking becomes calcium hydroxide and during curing by carbonation becomes calcium carbonate again. Carbon neutral material and best for stone walls. Little bit of pozzolan can be added to achieve feebly hydrolic mortar. NHL is modern substitute of lime that is way different ( worse for stone walls) than traditional lime mortar.
I think it depends upon where you live. I live at 57.5°N, in northern Scotland; external lime season is short here, as there isn't a big window for lime putty to dehydrate and carbonate sufficiently before the onslaught of winter. My cottage walls are granite, so impervious; I am repointing with NHL as sympathetically as possible but while also trying to maintain a balance between wicking and waterproofing. So the north-facing gable end and western wall - where the storms come from - uses NHL 3.5 in the joints but NHL 5 along the roof line. South and east walls can be a mix of NHL 3.5 and hot lime putty, depending upon the strength needed (because in part it is rubble infill). I want to use more hot lime - and will use that exclusively for the render coats - but I have to listen to what the cottage walls tell me and respect the power of the storms, which by the way are getter worse every year it seems. 😔
@@ateleskier7066 I don't think that in Scotland historically lime putty was used much for external pointing. Also most likely quicklime back in the day had more impurities in comparison to modern ones. I add pozzolan in the form of brick dust or trass and by doing it quicker in the initial set. It gets very hard on the surface after a week or so in humid conditions and even quicker in dry conditions. But so far I have only repointed sandstone and whinstone. But granite is very hard so maybe NHL is fine.
@@ateleskier7066 with granite I expect nhl is totally fine as it’s never going to be harder than the actual granite. Sandstone is a completely different matter.
We hear a lot about hot lime and we use them however, it does have limitations. It is important to know the history on this one. In Europe we have, for thousands of years used hydraulic limes by adding small or large amounts of pozzolan. In England we do have our own NHL which was often used in our historic buildings (grey chalk lime etc) Just as oranges are not the only fruit, neither is hot lime.
@@ironimp1 I recommend to watch Nigel Copsey's presentation on you tube. He gathered a lot of evidence how NHL ruined some of the historical buildings and what he thinks about NHL mortars used for stone walls and old bricks. I find it interesting.
For consistency of across mixes why not use a smaller tub to measure each substrate? Fill and flatten down and across the top with the trowel will get a better measurement. The big tub that is used here means that the sand and lime is thrown several times, instead of just tipped in from a small tub, causing the lime to be cast up into the air more than necessary. The strength of the mix ought to be adjusted according to the hardness/softness of the bricks to ensure that the mortar is the weaker.
Izzy. I am commenting on your video and really hope I can help anyone out on this subject. Lime is a very vague subject amongst tradesmen these days and a vast amount of knowledge has been lost over the past 80 years. As you know it's expensive and not a very good way to earn vast profit. I have lost countless nights sleep over it. 2m2 per day is about my estimate these days. If you get a sample tested you will find the mix to be around 1:1 maybe 1:2 All will depend on where you are in the country as material never generally travelled far. The use of soft sand is absolutely no benefit. If you can find the original sand source you are safe ( a local fresh water river bed source as in some area's of Kent) A sieve analysis will give you the correct sand grading ( part of the mortar test ) This all seems a lot of fuss but you will have the correct info on which to spec your mortar. I have been on some repointing jobs for more than 2 years. It's a lot of work to put it right and this is because the client is normally wealthy and can easily take one to the cleaners so you will have to correct it. There has been vast amounts of research into lime and it's a known fact that you cannot get modern lime to behave like the old this has a lot to do with purity and the old limes where dirty and this stems from the burning of the calcium. Our limes are pure in contrast mainly due to modern pollution concerns. The safest solution is to get your mix specified by a professional that has an indemnity insurance. It will cost you but you will have support. The good workmanship is down to you and that's another story.
Oh wow that's amazing Darrin, I, probably like everyone else besides a few people, had no idea about all of that information you just shared. Appreciate your knowledge on the subject ☺️ where have you been working buddy?
@@IzzytheBrickyThank you for your kind reply Izzy. I work in East Kent and 90% of my time on my own. Due to this I will often be employed by a well to do client that just wants their old property repaired etc. This often involves the use of Lime and reclaimed materials I have a few builder friends that just can't be arsed to fiddle about with stuff resulting in me having to sort out old traditional stuff. I was very fortunate to have been around old long gone tradesmen that knew how much I liked old work so they used to pass on all manner of knowledge. With old buildings come wealthy people and they normally have a very sharp educated brain. I never try to out smart them and try my best to get on with things properly this means you have to know the answer to their questions. Say a surgeon that can understand a lime technical leaflet in a few seconds. Lime is a big subject amongst the middle-class folks and they don't like dirty hands. The proper tuck pointing boys have all number of secrets on the subject that keeps them nicely employed. I have made some serious mistakes when working for ignorant builders that think the £15000 repoint is just big load of profit. If you know your product and have the right technique you can earn reasonable but I am afraid money makes people do funny things.
You my friend are clearly switched on and dilligent. I don't mean to be offensive to builders, but I've had a few comments thrown at me in local builders merchants when asking for NHL to the extent that I quickly learned to source exclusively from specialists. Your attention to detail, even if it is protectionism (which is smart) is impressive; not many people bother with sample testing and matching which is a big pity, as it's a fascinating subject on its own. I hope your customers recognise your differentiation, focus, effort and intelligence; keep going as you are and I guarantee you'll make a good name for yourself. To be fair to the average builder, lime work is slow and highly skilled, and many customers just don't want to pay for it. Up here (northern Scotland) there are plenty of rich folk (oil and gas) but they live in modern builds; the people in old cottages are the poorer folk like me who cannot afford to pay someone, so need to learn it from scratch and DIY. 😆 I wish you all the very best, but am pretty sure success and prosperity is going to follow you about like a lost dog if you carry on like this.
3.5nhl is probably too hard for most historical stone/brick applications. NHL 1 or 2 or even a mature lime putty mix would be better. The mortar should always be softer than the building material when fully hardened. The 3.5 refers to mortar strength in mpa developed at 28 days. Nhl can continue to get harder after this time. The mortar is intended to be sacrificial it should be the main conduit for damp evaporating in a wall, it is helpful to see mortar as shock absorber rather than a glue. Buildings tend to move due to ground changes, expansion and contraction, a well made lime mortar has flexibility which can accommodate movement without cracking. If cracking occurs lime mortar can self heal by migrating free lime to the site of the crack. Natural hydraulic lime can cure under water due to the chemical reaction of the constituents, ordinary lime putty has to rely on absorption of carbon dioxide from the atmosphere. It is important to dampen the substrate before application and protect the mortar from wind/ sunlight to keep as much water in the mix for it to cure successfully.
@@ingevansand9180 No, hydrated lime is mainly used as a plasticiser in bricklaying mortar, it is a poor substitute for lime putty. Hydrated lime is widely available whereas lime putty is generally sold by specialist suppliers who have a delivery network. Hydrated lime is often mistaken for hydraulic lime.
I'm repointing and rendering my stone cottage; the walls are granite, so even NHL 5 is softer. 😆 But you're absolutely right about permeability and wicking; there needs to be a balance. I have to use NHL 3.5 in many weather-facing aspects of my outer walls (winter storms are ferocious here, and temperatures of -6 to -10°C occur most years) but hot lime putty can be used exclusively indoors.
NHL also uses carbonation to achieve full strength, but initial primary set is chemical; another lovely feature of lime over OPC (cement) is that it just keeps on getter stronger over time. From page 36 of 'the bible' - English Heritage 'Mortars, Renders and Plasters', part of its 'Practical Building Conservation' series (ISBN 13: 978-0-7546-4559-7): _"When water is added to hyraulic quicklime the free lime reacts relatively quickly and hydrates (slakes) in the same way as non-hydraulic quicklime. If suffient water is available, the calcium silicates and aluminates will also hydrate (but more slowly than the calcium oxide) to form solid, interlocking crystals of calcium silicate hydrate and calcium aluminate hydrate; it is the latter process (which often starts within a few hours of water being added) that is responsible for the initial setting of hydraulic lime."_ _"Due to the hydraulic set, hydraulic lime gains initial strength faster than non-hydraulic lime. Further strength is gained due to both the continued hydration of the hydraulic components and the slow carbonation of the free lime in the mix, which can take several years."_ If using NHL also bear in mind that stronger isn't always better; it depends on how much breathability you require. The higher the strength, the lower the porosity and water permeability. I've had 'professional' builders tell me that I shouldn't use lime on the outside of my granite cottage up here in northern Scotland (because it won't keep the water out), yet local councils repair old stone bridges over flood-prone rivers using NHL 5, and it's fine. Here's the bible again: _"Ultimate strength of hydraulic lime is higher than that of non-hydraulic lime. However, there is an inverse relationship between hydraulicity and porosity and permeability: the greater the hydraulicity the lower the porosity and permeability."_ So if you need breathability more than strength (for example in my case for my kitchen wall) then hot lime putty (non-hydraulic) is better than NHL 2.
@@ateleskier7066Yes all lime sets with carbonation eventually. NHL just relies on water for its setting mainly. With your kitchen wall, being granite (which is mostly quartz) I highly doubt putty will make any real difference to nhl 2 or even 3.5 for that matter as any water vapour passing through the lime will hit that granite wall and slow down so much it will almost stop. Add that to anything other than clay paint on your wall and you’ve lost any benefit of putty. Obviously putty won’t hurt and it has many benefits in the right place, just not sure it’s necessary in your kitchen.
This is a really good video, very informative and useful, thank you! Out of interest when mixing up small batches (using a paddle mixer on the 4th floor of scaffolding) - do you mix 3:1 by weight or volume? there are a lot of opinions and I would value your input 👍🏻
Totally agree. Remember the cement shortage during lockdown (which my building merchant contacts say was faked btw)? I was bypassing it by buying lime; imagine how smug I was feeling!
Just a practical tip If like me you live in a stone cottage exposed to welsh mountain weather lime mortar doesn’t last a year it’s exposed to extreme weather I’ve tried it
36 years at this game Izzy and I know almost nothing about lime . We only used it for the first time last year when we worked with the A&E boys . Every day is a school day . Those mics work well too, couldn’t hear the mixer 🎤👌🏼🧱👍🏽
Thanks so much, good to see your exact recipe. I'm researching for completely covering an old stone interior wall in Italy. I first need to do a round of "dubbing out" to roughly fill in the very uneven original mortar (never pointed, it was a barn....albeit a very thick-walled and sturdy one). Is this mix you describe here good for dubbing out? I'm not clear on what is the best ratios of soft sand, sharp sand, and NHL for filling and levelling, RATHER than just repointing. Thanks!
If it's an internal wall I'd be opting for hot lime putty mixed on site rather than NHL; far better for the building if you don't need rapid strength. You _can_ use NHL but I wouldn't recommend anything more than 2. But I'm an amateur so take what I say with caution - consult a genuine expert. ;-)
Hey Isaac, is it ok to use any type of lime mortar like ( hydrated like with sand ) like “ brixment type S , it has lime and cement we add the sand over old lime mortar….are this ok to use over like work ? How do you text if is lime or cement? Thanks man God bless you.
Just a note...those masks are ok to begin with but over years the rubber perishes and splits...I use masks almost daily and now I would never buy anything other than sundstroms...about the same price but far superior! I'm a chippy of 20yrs fyi and my decorator agrees the same 👍
Izzy you are confusing hydrolic lime with hydrated lime. You should not knock it up the next day as hydrolic will loose its chemical strength same as cement its a chemical setting process not a carbonating process like hydrated lime which you could knock back up any time
Hi, can I ask you what sand you would use for a 120 year old house with lime mortar? I keep getting told sharp is best but can you use a mix of sharp and plastering dav to be able to use in a mortar gun? I do re-pointing now and again but only with traditional sand and cement in the guns. Thanks
Don't use a gun! I'm only saying that because that's what everyone I encounter who knows their business with lime says this, I think largely because it doesn't pack it enough and can lead to voids. And it's also not traditional of course. The problem with sharp sand is the lower level of hexagonal close packing relative to fine sand; i.e. the water-retaining spaces are larger - which water runs out of - and the surface area is lower so adsorption (not aBsorption) isn't as great, so it holds less water. (The larger the particle, the larger the space between them when they are pushed together.) I've been repointing in my old kitchen and started with sharp sand - because it closely matched the old lime mortar I raked out - but am finding it hard to work. So I'm having to adapt by adding fine sand, just as this video showed (hooray!) to provide a matrix with smaller inter-particle spaces that increase adsorption and retains more water. You have to watch the mixing though, as too much water leads to cracking. My mixing isn't perfect yet which is my current main focus.
This is totally wrong on almost everything, why talk about something that you clearly dont have the most basic understanding of ? 1. NEVER use building sand with lime. Using two parts of building sand like this is categorically wrong and will produce a very poor mortar. This also looks like unwashed building sand, even worse, especially with NHL's. 2. USE a washed sharp or course sand for all the parts of the aggregate, preferably well graded, if a specific colour is required a very small portion of unwashed sand can be used to add colour. 3. NEVER let the mix ball up like he does, add in 2 parts sand and one lime first and then enough water to make the mix start rolling over immediately, do not flood the mix, add in the last part of sand. 4. You do not need to mix the first 3 parts dry for ten minutes, a minute would be fine just to blend the mix a bit. Once the last water has been added 10-15 minutes is fine for NHls. For best results mix for 15, leave for 5 to settle then mix again for 5. 5. NHLs Do react with water, that is the whole idea dummy ...... natural hydraulic lime...... its in the name ...... NHl 2 is 30/70 water/ air. NHL 3.5 60/40 NHl 5 80/20. Once mixed NHL 3.5 and 5 should be used fairly much straight away, especially in the summer. NHL 2 is more workable but will start to carbonate as soon as water its added. The only form of lime that reacts only with air is lime putty. Which he probably should have been using anyway. 6. NHLs are, at least 3.5 and 5, very strong compared to historic lime mixes. 5 is basically weak cement and too strong for everything apart from chimneys. 3.5 is again fairly strong but mixed at 1/3 is acceptable in exposed areas. NHL 2 is a better option or even lime putty with a pozzaline. Most important of all, never listen to some chump on CZcams who knows nothing about lime, stick to knocking up cement blocks mate.
I'm a total noob about this, but am trying to patch some small areas on an old house we bought. Can you recommend any particular pre-mixed lime mortar, and what do you think of the LIMELITE stuff? Cheers.
First off its getting into the wrong time of year for external lime work. If you have to do it now then a NHl is your only option, putty wont set enough before winter, or its not worth risking it anyway. you will not destroy your house using the limelite NHL 3.5 at 1 part lime to 3 parts sharp/grit sand. but a less strong lime might also be better. the key is to make he mortar the sacrificial element to the stone/brickwork. if the mortar is stonier than the brick/masonry then they get damaged. You're on the right path already so well done !@@Showing_the_car_
Pre mixed means lime putty. As above its a bit late in the year for that. Call a local lime merchant, in the south we have rose of Jericho. they are a great source of help and information.@@Showing_the_car_
One of the most informative, well explained videos I've seen. No daft music or gimmicks. Thankyou.
Thanks so much mate
Like the "shorts" Izzy. A good extra to the main vids, explaining in more detail various techniques, in this case, lime mortar. Nice one, appreciate you taking the time to do this. 👍
Izzy, I work as a volunteer on the Buildings Team at the Chiltern Open Air Museum. The Museum saves condemned buildings from the Chilterns, takes them down and rebuilds them on site using traditional methods of construction. At the moment we are repointing the Toll House from High Wycombe with lime mortar. I’ve never done this before but have seen your videos which I have shared with my co-workers; we all use your work as a guide and it’s beginning to look amazing. Thanks so much.
Hiya mate, that's amazing what your doing, restoring old buildings! Really pleased that my video was able to help you and your co workers 🙂🙂 please send me some pictures of the project ☺️
All the best
You can find PPE in the description below. If you'd like me to make a How to video on a topic your interested in, let me know in the comments below 👇
Side note regarding the mixer. Andy, from Bricklayers world wide, mentioned in my previous video, that using a paddle mixer (used for plastering) is a great alternative to using the bell mixer 💪
Proper lime mortar for stone buildings is hot lime mortar or lime putty. Lime powder or kibble ( calcium oxide) made from limestone rock ( calcium carbonate) during slacking becomes calcium hydroxide and during curing by carbonation becomes calcium carbonate again. Carbon neutral material and best for stone walls. Little bit of pozzolan can be added to achieve feebly hydrolic mortar. NHL is modern substitute of lime that is way different ( worse for stone walls) than traditional lime mortar.
I think it depends upon where you live. I live at 57.5°N, in northern Scotland; external lime season is short here, as there isn't a big window for lime putty to dehydrate and carbonate sufficiently before the onslaught of winter. My cottage walls are granite, so impervious; I am repointing with NHL as sympathetically as possible but while also trying to maintain a balance between wicking and waterproofing. So the north-facing gable end and western wall - where the storms come from - uses NHL 3.5 in the joints but NHL 5 along the roof line. South and east walls can be a mix of NHL 3.5 and hot lime putty, depending upon the strength needed (because in part it is rubble infill).
I want to use more hot lime - and will use that exclusively for the render coats - but I have to listen to what the cottage walls tell me and respect the power of the storms, which by the way are getter worse every year it seems. 😔
@@ateleskier7066 I don't think that in Scotland historically lime putty was used much for external pointing. Also most likely quicklime back in the day had more impurities in comparison to modern ones. I add pozzolan in the form of brick dust or trass and by doing it quicker in the initial set. It gets very hard on the surface after a week or so in humid conditions and even quicker in dry conditions. But so far I have only repointed sandstone and whinstone. But granite is very hard so maybe NHL is fine.
@@ateleskier7066 with granite I expect nhl is totally fine as it’s never going to be harder than the actual granite. Sandstone is a completely different matter.
We hear a lot about hot lime and we use them however, it does have limitations. It is important to know the history on this one. In Europe we have, for thousands of years used hydraulic limes by adding small or large amounts of pozzolan. In England we do have our own NHL which was often used in our historic buildings (grey chalk lime etc) Just as oranges are not the only fruit, neither is hot lime.
@@ironimp1 I recommend to watch Nigel Copsey's presentation on you tube. He gathered a lot of evidence how NHL ruined some of the historical buildings and what he thinks about NHL mortars used for stone walls and old bricks. I find it interesting.
For consistency of across mixes why not use a smaller tub to measure each substrate? Fill and flatten down and across the top with the trowel will get a better measurement. The big tub that is used here means that the sand and lime is thrown several times, instead of just tipped in from a small tub, causing the lime to be cast up into the air more than necessary. The strength of the mix ought to be adjusted according to the hardness/softness of the bricks to ensure that the mortar is the weaker.
3.5 is not the softest because its not 100% Lime
Try mixing you're mortar wetter and knocking it up the next day. 2:1 ratio is also an amazing ratio.
Izzy.
I am commenting on your video and really hope I can help anyone out on this subject.
Lime is a very vague subject amongst tradesmen these days and a vast amount of knowledge has been lost over the past 80 years.
As you know it's expensive and not a very good way to earn vast profit.
I have lost countless nights sleep over it.
2m2 per day is about my estimate these days.
If you get a sample tested you will find the mix to be around 1:1 maybe 1:2
All will depend on where you are in the country as material never generally travelled far.
The use of soft sand is absolutely no benefit.
If you can find the original sand source you are safe ( a local fresh water river bed source as in some area's of Kent)
A sieve analysis will give you the correct sand grading ( part of the mortar test )
This all seems a lot of fuss but you will have the correct info on which to spec your mortar.
I have been on some repointing jobs for more than 2 years.
It's a lot of work to put it right and this is because the client is normally wealthy and can easily take one to the cleaners so you will have to correct it.
There has been vast amounts of research into lime and it's a known fact that you cannot get modern lime to behave like the old this has a lot to do with purity and the old limes where dirty and this stems from the burning of the calcium.
Our limes are pure in contrast mainly due to modern pollution concerns.
The safest solution is to get your mix specified by a professional that has an indemnity insurance.
It will cost you but you will have support.
The good workmanship is down to you and that's another story.
Oh wow that's amazing Darrin, I, probably like everyone else besides a few people, had no idea about all of that information you just shared. Appreciate your knowledge on the subject ☺️ where have you been working buddy?
@@IzzytheBrickyThank you for your kind reply Izzy.
I work in East Kent and 90% of my time on my own.
Due to this I will often be employed by a well to do client that just wants their old property repaired etc.
This often involves the use of Lime and reclaimed materials I have a few builder friends that just can't be arsed to fiddle about with stuff resulting in me having to sort out old traditional stuff.
I was very fortunate to have been around old long gone tradesmen that knew how much I liked old work so they used to pass on all manner of knowledge.
With old buildings come wealthy people and they normally have a very sharp educated brain.
I never try to out smart them and try my best to get on with things properly this means you have to know the answer to their questions.
Say a surgeon that can understand a lime technical leaflet in a few seconds.
Lime is a big subject amongst the middle-class folks and they don't like dirty hands.
The proper tuck pointing boys have all number of secrets on the subject that keeps them nicely employed.
I have made some serious mistakes when working for ignorant builders that think the £15000 repoint is just big load of profit.
If you know your product and have the right technique you can earn reasonable but I am afraid money makes people do funny things.
great comment Darrin, thanks. Have you got your own channel? Lime is a fascinating subject and needs more people like you to spread the word!
You my friend are clearly switched on and dilligent. I don't mean to be offensive to builders, but I've had a few comments thrown at me in local builders merchants when asking for NHL to the extent that I quickly learned to source exclusively from specialists. Your attention to detail, even if it is protectionism (which is smart) is impressive; not many people bother with sample testing and matching which is a big pity, as it's a fascinating subject on its own.
I hope your customers recognise your differentiation, focus, effort and intelligence; keep going as you are and I guarantee you'll make a good name for yourself. To be fair to the average builder, lime work is slow and highly skilled, and many customers just don't want to pay for it. Up here (northern Scotland) there are plenty of rich folk (oil and gas) but they live in modern builds; the people in old cottages are the poorer folk like me who cannot afford to pay someone, so need to learn it from scratch and DIY. 😆
I wish you all the very best, but am pretty sure success and prosperity is going to follow you about like a lost dog if you carry on like this.
@@crooningbarber Thank you for taking the time to reply.
I hope life is going nicely for you.
Thanks Izzy, very informative.
Would it still be ok to use for pointing on a dry day today but rain forecast for tomorrow?
Really helpful video. Clear and concise. Thanks!
3.5nhl is probably too hard for most historical stone/brick applications. NHL 1 or 2 or even a mature lime putty mix would be better. The mortar should always be softer than the building material when fully hardened. The 3.5 refers to mortar strength in mpa developed at 28 days. Nhl can continue to get harder after this time. The mortar is intended to be sacrificial it should be the main conduit for damp evaporating in a wall, it is helpful to see mortar as shock absorber rather than a glue. Buildings tend to move due to ground changes, expansion and contraction, a well made lime mortar has flexibility which can accommodate movement without cracking. If cracking occurs lime mortar can self heal by migrating free lime to the site of the crack. Natural hydraulic lime can cure under water due to the chemical reaction of the constituents, ordinary lime putty has to rely on absorption of carbon dioxide from the atmosphere. It is important to dampen the substrate before application and protect the mortar from wind/ sunlight to keep as much water in the mix for it to cure successfully.
Is it better with hydrated lime?
@@ingevansand9180 No, hydrated lime is mainly used as a plasticiser in bricklaying mortar, it is a poor substitute for lime putty. Hydrated lime is widely available whereas lime putty is generally sold by specialist suppliers who have a delivery network. Hydrated lime is often mistaken for hydraulic lime.
Use a hotlime mix Calbux 90. 1 lime, 3 sharp sand. This way you know what you’re getting.
Fully agree. I only use hot lime now!
I'm repointing and rendering my stone cottage; the walls are granite, so even NHL 5 is softer. 😆
But you're absolutely right about permeability and wicking; there needs to be a balance. I have to use NHL 3.5 in many weather-facing aspects of my outer walls (winter storms are ferocious here, and temperatures of -6 to -10°C occur most years) but hot lime putty can be used exclusively indoors.
Always good to learn new things.
First time I saw Lime mortar getting used was Mr Songer's videos many moons ago 👍🏻
Hey Izzy, just subscribed mate.
Great video. Nice to seeing lime being used, great tutorial as well 👌
Excellent tutorial and very informative. You are a natural teacher. Many thanks and all the best.
Thanks so much Andrew! Have a great weekend
Thanks for this Izzy, great vid and very helpful
Nice to see the old skills being used
Thanks. Really clear and well put.
Boss mate! Thank you for uploading this!
NHL actually sets because of the water not air carbonation.
You’re thinking of hydrated lime rather than natural hydraulic lime.
NHL also uses carbonation to achieve full strength, but initial primary set is chemical; another lovely feature of lime over OPC (cement) is that it just keeps on getter stronger over time.
From page 36 of 'the bible' - English Heritage 'Mortars, Renders and Plasters', part of its 'Practical Building Conservation' series (ISBN 13: 978-0-7546-4559-7):
_"When water is added to hyraulic quicklime the free lime reacts relatively quickly and hydrates (slakes) in the same way as non-hydraulic quicklime. If suffient water is available, the calcium silicates and aluminates will also hydrate (but more slowly than the calcium oxide) to form solid, interlocking crystals of calcium silicate hydrate and calcium aluminate hydrate; it is the latter process (which often starts within a few hours of water being added) that is responsible for the initial setting of hydraulic lime."_
_"Due to the hydraulic set, hydraulic lime gains initial strength faster than non-hydraulic lime. Further strength is gained due to both the continued hydration of the hydraulic components and the slow carbonation of the free lime in the mix, which can take several years."_
If using NHL also bear in mind that stronger isn't always better; it depends on how much breathability you require. The higher the strength, the lower the porosity and water permeability. I've had 'professional' builders tell me that I shouldn't use lime on the outside of my granite cottage up here in northern Scotland (because it won't keep the water out), yet local councils repair old stone bridges over flood-prone rivers using NHL 5, and it's fine. Here's the bible again:
_"Ultimate strength of hydraulic lime is higher than that of non-hydraulic lime. However, there is an inverse relationship between hydraulicity and porosity and permeability: the greater the hydraulicity the lower the porosity and permeability."_
So if you need breathability more than strength (for example in my case for my kitchen wall) then hot lime putty (non-hydraulic) is better than NHL 2.
@@ateleskier7066Yes all lime sets with carbonation eventually. NHL just relies on water for its setting mainly.
With your kitchen wall, being granite (which is mostly quartz) I highly doubt putty will make any real difference to nhl 2 or even 3.5 for that matter as any water vapour passing through the lime will hit that granite wall and slow down so much it will almost stop.
Add that to anything other than clay paint on your wall and you’ve lost any benefit of putty.
Obviously putty won’t hurt and it has many benefits in the right place, just not sure it’s necessary in your kitchen.
Just using plastering sand and lime makes a great flush joint by finishing with a wire brush, gives it a heritage look
This is a really good video, very informative and useful, thank you! Out of interest when mixing up small batches (using a paddle mixer on the 4th floor of scaffolding) - do you mix 3:1 by weight or volume? there are a lot of opinions and I would value your input 👍🏻
Hiya mate, I do it by volume, not thought about doing it by weight☺️
It's always volume.
Good video, Izzy. Lime mortar is such a great product. We need to get away from Portland.
Thanks mate glad you enjoyed it!
Totally agree.
Remember the cement shortage during lockdown (which my building merchant contacts say was faked btw)? I was bypassing it by buying lime; imagine how smug I was feeling!
Thanks for this Izzy !! I’ve a rock render job coming up and want to point with lime , kind regards Adrian (RockCraft)
@@adrianhatton8793 ayup mate hope your doing really well! Keep seeing your work on IG, looks amazing!
Can you knock up without a mixer ? By hand ?
Izzy. Love the videos, however, NHL 3.5 is too hard for older buildings. NHL 2.. maybe but preferable to use Quicklime, with soft bricks.
Top notch mate as ever 👏😎
Alright Izzy been really busy last few weeks so I AV a bit of catching up to do hope your well bro
Just a practical tip
If like me you live in a stone cottage exposed to welsh mountain weather lime mortar doesn’t last a year it’s exposed to extreme weather I’ve tried it
You can NHL 5 for areas like that.
A suggestion to stop it from balling, put a rock or two in the mixer.
Helpful video, thanks! I need to repoint a Victorian retaining wall. How can I find out what mix I should use? The existing joints seem very soft.
I'd go for quite a weak mix. Perhaps 4/1 or even 5/1 do a little research 😊
@@IzzytheBricky Thank you, I was thinking 5/1. This is research 😉
Hi,
Can I use hydrated lime and sand 1:3 to cover cinder blocks walls in my basement?
I have found 3.5 to be far too hard. It doesn’t allow walls to breathe. Even some NHL 2 are too hard. I have reverted to using hotlime instead.
Wots hot lime ?
Hotline is the way forward. The mortar must be softer than the stone/brick otherwise there is no point.
Stick a dustbin lid over the mixer izzy
36 years at this game Izzy and I know almost nothing about lime . We only used it for the first time last year when we worked with the A&E boys .
Every day is a school day .
Those mics work well too, couldn’t hear the mixer 🎤👌🏼🧱👍🏽
Should all repointing be done with a lime mortar mix to allow the building to breathe or are there occasions where sand and cement will suffice?
Hi Izzy is there no requirement for plasticiser? I am about to start grinding out and repoint my 1930s house in Cheshire
🎉 nice...what you use to record your videos m8?
Nice vid btw
Izzy that was confusing the way you explained the ratio
So is it 2 parts sand 1 part sharp sand and 1 part NHL????
Great video - thanks. But no eye protection when throwing lime around......goggles?
Nice video 👍
Thanks so much, good to see your exact recipe. I'm researching for completely covering an old stone interior wall in Italy. I first need to do a round of "dubbing out" to roughly fill in the very uneven original mortar (never pointed, it was a barn....albeit a very thick-walled and sturdy one). Is this mix you describe here good for dubbing out? I'm not clear on what is the best ratios of soft sand, sharp sand, and NHL for filling and levelling, RATHER than just repointing. Thanks!
If it's an internal wall I'd be opting for hot lime putty mixed on site rather than NHL; far better for the building if you don't need rapid strength. You _can_ use NHL but I wouldn't recommend anything more than 2. But I'm an amateur so take what I say with caution - consult a genuine expert. ;-)
Eye protection? Otherwise really good
Hey Isaac, is it ok to use any type of lime mortar like ( hydrated like with sand ) like “ brixment type S , it has lime and cement we add the sand over old lime mortar….are this ok to use over like work ?
How do you text if is lime or cement?
Thanks man God bless you.
Another question: Why not use a lime putty?
Look at the state of your tools and mixer.
Hi there, do you use only the 3.5 nhl or you use cement based pointing too?
Just a note...those masks are ok to begin with but over years the rubber perishes and splits...I use masks almost daily and now I would never buy anything other than sundstroms...about the same price but far superior! I'm a chippy of 20yrs fyi and my decorator agrees the same 👍
Izzy you are confusing hydrolic lime with hydrated lime.
You should not knock it up the next day as hydrolic will loose its chemical strength same as cement its a chemical setting process not a carbonating process like hydrated lime which you could knock back up any time
You can mix it then store it in tubs with water on top and a lid.
Not this stuff, you need quicklime to be able to store, not nhl i believe.
Yes, you will need lime hydrated lime rather than nhl for long term storage, nhl sets with moisture
Hi , can I use hydrated or NHL for any lime work?
How do you test if is Lime ?
Thanks
Any tips for removing stains caused when you add water to the old joint after you have cleaned it out?
Just roll a new one.
(Sorry.)
Hi, can I ask you what sand you would use for a 120 year old house with lime mortar? I keep getting told sharp is best but can you use a mix of sharp and plastering dav to be able to use in a mortar gun? I do re-pointing now and again but only with traditional sand and cement in the guns.
Thanks
Don't use a gun! I'm only saying that because that's what everyone I encounter who knows their business with lime says this, I think largely because it doesn't pack it enough and can lead to voids. And it's also not traditional of course.
The problem with sharp sand is the lower level of hexagonal close packing relative to fine sand; i.e. the water-retaining spaces are larger - which water runs out of - and the surface area is lower so adsorption (not aBsorption) isn't as great, so it holds less water. (The larger the particle, the larger the space between them when they are pushed together.) I've been repointing in my old kitchen and started with sharp sand - because it closely matched the old lime mortar I raked out - but am finding it hard to work. So I'm having to adapt by adding fine sand, just as this video showed (hooray!) to provide a matrix with smaller inter-particle spaces that increase adsorption and retains more water. You have to watch the mixing though, as too much water leads to cracking. My mixing isn't perfect yet which is my current main focus.
Its same way that i do it buddy👍
Where did you get that hawk ?
Safety goggles, that lime mess up👀 end in 😭
I hear 3.5 is not 100% Lime but contains a high percentage of impurities
You are right. It’s almost as hard as cement. Nothing like the old traditional lime mortars. I always use hot lime.
Shame they only stock hydrated lime locally. You have to pay expensive shipping fees to get any hydraulic 3.5.
No bad I'm a Mason for 26 years an still doing it lean something new early bad
What price per square metre these days ? Cut and struck ! I presume! TIA
He covers cost in the video that came out on Monday. 👍🏻
This is totally wrong on almost everything, why talk about something that you clearly dont have the most basic understanding of ?
1. NEVER use building sand with lime. Using two parts of building sand like this is categorically wrong and will produce a very poor mortar. This also looks like unwashed building sand, even worse, especially with NHL's.
2. USE a washed sharp or course sand for all the parts of the aggregate, preferably well graded, if a specific colour is required a very small portion of unwashed sand can be used to add colour.
3. NEVER let the mix ball up like he does, add in 2 parts sand and one lime first and then enough water to make the mix start rolling over immediately, do not flood the mix, add in the last part of sand.
4. You do not need to mix the first 3 parts dry for ten minutes, a minute would be fine just to blend the mix a bit. Once the last water has been added 10-15 minutes is fine for NHls. For best results mix for 15, leave for 5 to settle then mix again for 5.
5. NHLs Do react with water, that is the whole idea dummy ...... natural hydraulic lime...... its in the name ...... NHl 2 is 30/70 water/ air. NHL 3.5 60/40 NHl 5 80/20. Once mixed NHL 3.5 and 5 should be used fairly much straight away, especially in the summer. NHL 2 is more workable but will start to carbonate as soon as water its added. The only form of lime that reacts only with air is lime putty. Which he probably should have been using anyway.
6. NHLs are, at least 3.5 and 5, very strong compared to historic lime mixes. 5 is basically weak cement and too strong for everything apart from chimneys. 3.5 is again fairly strong but mixed at 1/3 is acceptable in exposed areas. NHL 2 is a better option or even lime putty with a pozzaline.
Most important of all, never listen to some chump on CZcams who knows nothing about lime, stick to knocking up cement blocks mate.
Mixer isn't even on the stand. You need these mixers tipped forward to create the slap when mixing
I'm a total noob about this, but am trying to patch some small areas on an old house we bought. Can you recommend any particular pre-mixed lime mortar, and what do you think of the LIMELITE stuff? Cheers.
First off its getting into the wrong time of year for external lime work. If you have to do it now then a NHl is your only option, putty wont set enough before winter, or its not worth risking it anyway. you will not destroy your house using the limelite NHL 3.5 at 1 part lime to 3 parts sharp/grit sand. but a less strong lime might also be better. the key is to make he mortar the sacrificial element to the stone/brickwork. if the mortar is stonier than the brick/masonry then they get damaged. You're on the right path already so well done !@@Showing_the_car_
@@user-xj5mh3kh9j Can you recommend any particular pre-mixed lime mortar? what do you think about LIMELITE plaster?
Pre mixed means lime putty. As above its a bit late in the year for that. Call a local lime merchant, in the south we have rose of Jericho. they are a great source of help and information.@@Showing_the_car_
Ever day I hate spell check
Don’t teach people to put there hand in a mixer it’s bad practice
Their.
@@davidcameron7597 why? Theirs just no need? Troll.
One of my first memories from primary school is hearing about someone’s dad who had broken his arm by reaching into a cement mixer
Ft