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biffvernon
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For general bicklaying use hydrated lime. Hydraulic is for harbour works, canal locks and, maybe, exposed chimneys.
Well graded, meaning a variety of grain size, is good.
Sharp, meaning a high proportion of the larger grain sizes, is good.
Washed, meaning a low proportion of fine material, is not needed. The fines are just fine.
Plasterers sand probably means the opposite of well graded sharp.
Bagged probably means expensive.
Most period houses were probably built with mortar whose aggregate was dug up from within a handcart's push of the site. What's in your backgarden?
Well graded, meaning a variety of grain size, is good.
Sharp, meaning a high proportion of the larger grain sizes, is good.
Washed, meaning a low proportion of fine material, is not needed. The fines are just fine.
Plasterers sand probably means the opposite of well graded sharp.
Bagged probably means expensive.
Most period houses were probably built with mortar whose aggregate was dug up from within a handcart's push of the site. What's in your backgarden?
I’ve been told by my local lime distributors (Chalk Down Lime) who sell both slaked lime(lime putty) and bagged hydraulic lime(the white powdered stuff) that the latter Hydraulic lime is more suitable for outside brickwork as its more durable. I’ve also experienced this myself where I originally had an area of outside wall repointed with a ready mixed bag of sand and lime putty from CDL. This pointing was done in good weather during the spring of last year and I live in a relatively frost free south coast location, but after six months or so there was evidence of the pointing failing, deterioration on the surface and small piles of sand on the ground. I have since had the same area of wall repointed again using a mix of 3 sand to 1 Hydraulic lime (Singleton Birch Lincolnshire Hydraulic lime) and this has held up very well. I am proposing to do some internal brickwork repair using the same mix but the sands available at the local builders merchants only comprise of Builders sand (very muddy and loamy in consistency and an orangey colour) Plasterers sand ( a much dryer sharper feel and lighter yellow colour) or Concreting sand ( a very coarse gravely sand with what appears to be the odd bit of pea shingle mixed in and more grey/buff coloured) I figured therefore that the Plasterers sand would be the best option to go for and seeing that I only have a few small areas of repair to deal with, that the bagged sands would be more consistant and clean or should I be sourcing specialist varieties, silver sand etc.(A much more expensive option).
Nemesis
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Yes but hydraulic isn't in general anything like as breathable as non-hydraulic!
Lime putty is in my h.o. the best, but expensive. Bagged hydrate, (not hydraulic) if fresh and allowed to make a putty, shouldn't fail. Ensure it hasn't already carbonated in the bag - which should be lined with placcy.
Lime putty is in my h.o. the best, but expensive. Bagged hydrate, (not hydraulic) if fresh and allowed to make a putty, shouldn't fail. Ensure it hasn't already carbonated in the bag - which should be lined with placcy.
The bagged lime that I have is labeled “Singleton Birch Hydraulic Lincolnshire lime hl2” I believe you can also get hl3 or 3.5 and hl 5. It is not labeled “Hydrate” although with my limited understanding of lime, this is what I understand it to be.
Correct me if I’m wrong but am I right in thinking that lime is produced by firing limestone in a kiln. The unstable residue from this firing is then stablised by adding water.
Excess water produces slaked lime (lime putty) or Hydrated lime which falls to the bottom of the water. This sets through carbonation with the air
Measured quantities of water produces the powder (hydrate) or Hydraulic lime which is able to take on more water and sets through a combination of drying and carbonation.
A couple of questions:-
What would my lime look like if it has carbonated in the bag? Presumably it would have gone hard in the bag like cement. This bag ( paper) is unopened, has been kept relatively dry(in an unheated indoor space) and is about 3 months old. I notice that some suppliers store their bagged lime in little more than a cow shed.
Is mixing measured quantities of bagged Hydraulic lime,(hydrate) sand and water equivalent to making a putty or are you suggesting that it has to be immersed in water(slaked) and then make a sand and lime mix using the resulting putty?
I might as well buy the ready made putty rather than trying to get modern builders to do the slaking.
Why do you think my original ready mixed sand lime putty pointing failed?
This was supplied in sealed plastic bags and was used immediatley.
What type of sand should I be using ?
Many thanks
Correct me if I’m wrong but am I right in thinking that lime is produced by firing limestone in a kiln. The unstable residue from this firing is then stablised by adding water.
Excess water produces slaked lime (lime putty) or Hydrated lime which falls to the bottom of the water. This sets through carbonation with the air
Measured quantities of water produces the powder (hydrate) or Hydraulic lime which is able to take on more water and sets through a combination of drying and carbonation.
A couple of questions:-
What would my lime look like if it has carbonated in the bag? Presumably it would have gone hard in the bag like cement. This bag ( paper) is unopened, has been kept relatively dry(in an unheated indoor space) and is about 3 months old. I notice that some suppliers store their bagged lime in little more than a cow shed.
Is mixing measured quantities of bagged Hydraulic lime,(hydrate) sand and water equivalent to making a putty or are you suggesting that it has to be immersed in water(slaked) and then make a sand and lime mix using the resulting putty?
I might as well buy the ready made putty rather than trying to get modern builders to do the slaking.
Why do you think my original ready mixed sand lime putty pointing failed?
This was supplied in sealed plastic bags and was used immediatley.
What type of sand should I be using ?
Many thanks
Nemesis
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Hydraulic lime and hydrated lime are different things. Both come as powdered lime though.
I'm not a chemist, but it's usual to use hydraulic only where a chemical set is required eg underwater - or where it's very exposed - chimneys - where feebly hydraulic is often recommended.
For other places, in general non-hydraulic limes are recommended. That sets through carbonation.
I'm not a chemist, but it's usual to use hydraulic only where a chemical set is required eg underwater - or where it's very exposed - chimneys - where feebly hydraulic is often recommended.
For other places, in general non-hydraulic limes are recommended. That sets through carbonation.
biffvernon
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Don't blame the fact that it was hydrated lime. There was something else going wrong.
Whilst Ive always loved old buildings, Ive only started looking at the intricacies of their building techniques in the last couple of years having bought one for myself. The one hurdle I cant seem to get over is understanding lime and I get particularly confused with the words Hydraulic and Hydrated - My understanding is that Hydraulic lime sets with water(chemical set) and Hydrated lime sets with air (carbonation)Am I right or wrong so far?
Nemesis said:
Powdered Hydrated Lime - Would that not be Quick Lime (Calcium Oxide) and hence gets rather hot when water is added?
(I'm going on Mike Wye Lime course in a couple of weeks so will find out then I guess. It would be useful to know beforehand though as the types of lime has confused me in the past.)
(I'm going on Mike Wye Lime course in a couple of weeks so will find out then I guess. It would be useful to know beforehand though as the types of lime has confused me in the past.)
I was also confused before I started reading this forum. All the info is here, either in past threads, on information pages accessed off the main page, or in Lime suppliers' site or others. Haven't time to give you all the references - follow them yourself 
However - very briefly - Quick Lime, when slaked with excess water becomes putty (which keeps better), but with JUST the right amount of water it becomes "dry hydrate", "hydrated lime". "bag lime", AKA the ordinary stuff bought in bags from builders merchants and beloved of Biff when mixed with mud from his garden. All of this sets by carbonating (combining with atmospheric CO2) slowly, and is more flexible, breathable etc. etc. However, it will not set in water or wet conditions, which is why it will keep almost forever when mixed to a putty and kept with a layer of water on top. This combining with CO2 is also what may happen prematurely in the bag to dry bagged lime if its not fresh. As it will not set in water, it is not so robust for use in exposed conditions as HYDRAULIC lime, which sets by another sort of chemical action, and is so called because it will set in water (like cement does - which is why it can be used for bridge foundations, harbour walls etc.) Hydraulic Lime comes in various grades, from weakly to "eminently" hydraulic depending on how much water it will stand (to simpify!) and confusingly, it also comes as bags of dry powder. This hydraulic quality is imparted by the presence of natural impurities, or added things like brick-dust, volcanic ash etc. called pozzolans (spelling??).
I hope (O Forum experts) I have got all this basically right - do I pass the PPUK Forum First Year Exam?
However - very briefly - Quick Lime, when slaked with excess water becomes putty (which keeps better), but with JUST the right amount of water it becomes "dry hydrate", "hydrated lime". "bag lime", AKA the ordinary stuff bought in bags from builders merchants and beloved of Biff when mixed with mud from his garden. All of this sets by carbonating (combining with atmospheric CO2) slowly, and is more flexible, breathable etc. etc. However, it will not set in water or wet conditions, which is why it will keep almost forever when mixed to a putty and kept with a layer of water on top. This combining with CO2 is also what may happen prematurely in the bag to dry bagged lime if its not fresh. As it will not set in water, it is not so robust for use in exposed conditions as HYDRAULIC lime, which sets by another sort of chemical action, and is so called because it will set in water (like cement does - which is why it can be used for bridge foundations, harbour walls etc.) Hydraulic Lime comes in various grades, from weakly to "eminently" hydraulic depending on how much water it will stand (to simpify!) and confusingly, it also comes as bags of dry powder. This hydraulic quality is imparted by the presence of natural impurities, or added things like brick-dust, volcanic ash etc. called pozzolans (spelling??).I hope (O Forum experts) I have got all this basically right - do I pass the PPUK Forum First Year Exam?
Thanks piper. This has been extremely helpful.
What would be the purpose of using Dry bagged hydrated lime over lime putty? Is it perhaps cheaper and is it therefore inferior to lime putty?
Is the builder’s merchant stuff inferior to that available from specialist suppliers?
Our local supplier of lime products is Chalk Down Lime in East Sussex who brand themselves as producers of Slaked lime and other traditional building materials. Their product list is very comprehensive and includes: Mature lime putty, Hydraulic lime (English or French), Ready mixed Lime mortars Coarse and medium with or without hair, Fine mortar, Finish for plastering, Traditional hot slaked ready mixed mortar coarse, medium and fine, Plaster of Paris. Grade D best plastering Sand, Fine silica sand, Various dust additives for mortar plus limewash ,pigments, Hair, wealden clay’ daub and timber products including Pine, Chesnut and Oak laths (sawn and riven) But there is no mention of bagged Lime or dry hydrated lime which surprises me?
Just to confuse things further. The bag of lime I have was purchased from the above supplier and as previously mentioned it is labeled in large letters as follows:
Singleton Birch Quality Lime Products
Hydraulic Lincolnshire Lime
However below this title there is a safety data box containing a large Irritant symbol and the title within that data box is “Calcium Hydroxide Ca(OH)2 Hydrated Lime”
So what do you think I have Hydraulic lime or Hydrated Lime?
Assuming I already have or can get hold of some Dry bagged hydrated lime. How would I use it? Do I just mix it up with sand and water and if so to what proportions?
And back to my original question, what type of sand should one use with lime – Is plasterers sand from the local Builders merchant sufficient?
What would be the purpose of using Dry bagged hydrated lime over lime putty? Is it perhaps cheaper and is it therefore inferior to lime putty?
Is the builder’s merchant stuff inferior to that available from specialist suppliers?
Our local supplier of lime products is Chalk Down Lime in East Sussex who brand themselves as producers of Slaked lime and other traditional building materials. Their product list is very comprehensive and includes: Mature lime putty, Hydraulic lime (English or French), Ready mixed Lime mortars Coarse and medium with or without hair, Fine mortar, Finish for plastering, Traditional hot slaked ready mixed mortar coarse, medium and fine, Plaster of Paris. Grade D best plastering Sand, Fine silica sand, Various dust additives for mortar plus limewash ,pigments, Hair, wealden clay’ daub and timber products including Pine, Chesnut and Oak laths (sawn and riven) But there is no mention of bagged Lime or dry hydrated lime which surprises me?
Just to confuse things further. The bag of lime I have was purchased from the above supplier and as previously mentioned it is labeled in large letters as follows:
Singleton Birch Quality Lime Products
Hydraulic Lincolnshire Lime
However below this title there is a safety data box containing a large Irritant symbol and the title within that data box is “Calcium Hydroxide Ca(OH)2 Hydrated Lime”
So what do you think I have Hydraulic lime or Hydrated Lime?
Assuming I already have or can get hold of some Dry bagged hydrated lime. How would I use it? Do I just mix it up with sand and water and if so to what proportions?
And back to my original question, what type of sand should one use with lime – Is plasterers sand from the local Builders merchant sufficient?
michael said:
If they say it is Hydraulic, then one must assume you have Hydraulic Lime, but it is also hydrated in that it has been slaked with water. Logically, I suppose one could say that all Hydraulic Lime is also hydrated, but not all Hydrated Lime is hydraulic. The term Hydraulic Lime does mean that it has these extra additives to speed setting, and make it more resilient in wet conditions etc. However, most experts seem to think that it is not so good as non-hydraulic (whether made from dry powder or bought as wet putty) re. flexibility/breathability and all the other reasons we use lime mortar in old buildings. As to what is best in your situation, or to answer your sand question, I'm afraid I have very little practical experience, just academic knowledge. There are other contributors here who have vast experience - (and sometimes conflicting opinions) perhaps they can help.
As to why your specialist suppliers don't stock plain bagged Hydrate - I guess it is because they ARE specialists, after all the bog-standard dry bagged stuff can be got from ordinary builders merchants. Most "ordinary" builders - and in fact most conservation experts recommended this until just a few years ago - mix at least some ordinary cement into the mix in order to give pure (non-hyraulic) lime the "hydraulic" quality needed for outside work. However, now the received wisdom is to use pure lime as much as possible, and as weakly hydraulic as you can get away with if weather resistance is required. Only a few months ago a (good quality) local builder was going on to me about this **** architect who specified fancy lime which came from France (!patriotic outrage) instead of mixing in the ordinary stuff they regularly use with cement. Up here, I live in a limestone area, where all the old houses are built in limestone, there are limestone and lime-mortar walls all over the village and there are the remains of old lime-kilns everywhere - but all the specialist lime suppliers are many miles away. The vast majority of local builders use normal cement, and there is plenty of barn conversion and house renovation going on which just uses the standard sand/cement mix. However, use of lime is creeping in - even here, in real limestone country.
Thanks piper
The repointing I had done with the what I think is "hydraulic lime" has held up pretty well and was probably the right decision as I'm only 500 yards or so from the sea and that part of the building often takes the brunt of wind driven rain which is probably why the pointing failed in the first place. As the remaining work that I have to do is internal, I think I'll have to confront my "specialist" lime supplier and find out exactly what I have got (hydrated or Hydraulic) and probably end up discarding my £15 per bag from him for a £3 or less per bag from the builders merchants or should I be going down the lime putty route?.I only have to relay about 30 bricks on the inside face of the wall.
Thanks again for your time. I hope someone out there can advise me on the sand. maybe the cheapo plasterers sand from the builders merchant will also be ok. Just to recap, If I use the Dry hydrated lime what mix would you recommend - 3 sand to 1 lime?
The repointing I had done with the what I think is "hydraulic lime" has held up pretty well and was probably the right decision as I'm only 500 yards or so from the sea and that part of the building often takes the brunt of wind driven rain which is probably why the pointing failed in the first place. As the remaining work that I have to do is internal, I think I'll have to confront my "specialist" lime supplier and find out exactly what I have got (hydrated or Hydraulic) and probably end up discarding my £15 per bag from him for a £3 or less per bag from the builders merchants or should I be going down the lime putty route?.I only have to relay about 30 bricks on the inside face of the wall.
Thanks again for your time. I hope someone out there can advise me on the sand. maybe the cheapo plasterers sand from the builders merchant will also be ok. Just to recap, If I use the Dry hydrated lime what mix would you recommend - 3 sand to 1 lime?
michael.
As I said, I'm sure your supplier as a reputable specialist would not misrepresent what they sell you - so it's bound to be hydraulic. And using it has got to be better than using the normal builder's sand/cement mix. So now you've got it don't discard it - use it. In future though, unless your work is very exposed, the £3 per bag stuff from the builders merchant would seem to be the stuff to use.
I think a mix of 3 sand to 1 of lime would be what most people here recommend. I have done small bits of work myself with that mix and it has worked fine. The general opinion seems to be that it's better to make a putty with the powdered lime first by adding water - this is both cheaper and easier than paying for the transport of the water in heavy tubs of putty - and leaving for a day or two to "mature", then mixing it with the sand. Once it's covered with water you can keep it fairly indefinitely it seems. I can't comment on this from experience, as I have mixed it dry myself, and it's been difficult to get a good uniform mix without the lime forming little lumps. Next time I'll try the home-made putty method, though as I said - there are professional builders here who are vastly more experienced in doing the actual work than me. I've just saved them some time by writing the basic theory for you No-one has jumped in to correct me yet, so I'm trusting I've got it right!
As I said, I'm sure your supplier as a reputable specialist would not misrepresent what they sell you - so it's bound to be hydraulic. And using it has got to be better than using the normal builder's sand/cement mix. So now you've got it don't discard it - use it. In future though, unless your work is very exposed, the £3 per bag stuff from the builders merchant would seem to be the stuff to use.
I think a mix of 3 sand to 1 of lime would be what most people here recommend. I have done small bits of work myself with that mix and it has worked fine. The general opinion seems to be that it's better to make a putty with the powdered lime first by adding water - this is both cheaper and easier than paying for the transport of the water in heavy tubs of putty - and leaving for a day or two to "mature", then mixing it with the sand. Once it's covered with water you can keep it fairly indefinitely it seems. I can't comment on this from experience, as I have mixed it dry myself, and it's been difficult to get a good uniform mix without the lime forming little lumps. Next time I'll try the home-made putty method, though as I said - there are professional builders here who are vastly more experienced in doing the actual work than me. I've just saved them some time by writing the basic theory for you
No-one has jumped in to correct me yet, so I'm trusting I've got it right!chuckey
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I too have been down this lime mortar route. having bought a limestone cottage that needed total re-pointing, I enrolled on a one days lime course (the Lime Centre Wichester). One thing the guy went on about was the grade of sand (BSS 1199/1200).
When I ws about to start the job, I went to the local builders merchants to buy the sand and asked about the BSS no.s, alot of blank stares, so I got the name of the actual quarry where the sand came from. I phoned up the quarry and spoke to the manager about his grade of sand and Lime mortar. Well !, this guy, 1, told me NOT to use his sand and 2, sent me a lot of litrature from SPAB, about re-pointing ancient buildings.
So back to square one, however I got to chat up a lecturer who was employed to do " Using Lime mortar" courses, anyway, the lecturer recommended some sand from a builders merchants some 40 Miles away.
I Have re-pointed the cottage with NHL5 lime + 2 1/2 parts sharp sand and the end results is extremely disapointing, water pees through the walls around the windows reveals.
I have had the sand through the BSS sieves and it is very good. When the weather improves I shall do some experiments in using raw linseed oil as an ad-mix, to see how the colour changes.
You guys that recommend non- hydraulic lime, how water proof is it?
Thoroughly p****d off, Frank
When I ws about to start the job, I went to the local builders merchants to buy the sand and asked about the BSS no.s, alot of blank stares, so I got the name of the actual quarry where the sand came from. I phoned up the quarry and spoke to the manager about his grade of sand and Lime mortar. Well !, this guy, 1, told me NOT to use his sand and 2, sent me a lot of litrature from SPAB, about re-pointing ancient buildings.
So back to square one, however I got to chat up a lecturer who was employed to do " Using Lime mortar" courses, anyway, the lecturer recommended some sand from a builders merchants some 40 Miles away.
I Have re-pointed the cottage with NHL5 lime + 2 1/2 parts sharp sand and the end results is extremely disapointing, water pees through the walls around the windows reveals.
I have had the sand through the BSS sieves and it is very good. When the weather improves I shall do some experiments in using raw linseed oil as an ad-mix, to see how the colour changes.
You guys that recommend non- hydraulic lime, how water proof is it?
Thoroughly p****d off, Frank
biffvernon
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I was going to answer some of your questions, Michael, but Piper has done an excellent job.
I've been to Singleton Birch. SPAB organized a tour last year round their quarries and kilns and we had some very imformative talks from their technical people. Two of the very few English quarries where there is limestone with naturally hydraulic properties are here in Lincolnshire. That's what Singleton Birch are using. They hope to increase their production of hydraulic limes over the next couple of years, investing millions in a dedicated kiln.
Although most period building used just hydrated lime it is thought that much of London's 18th and 19th century housing used a lime that was very feebly hydraulic - maybe a '1' on the normal 2. 3.5 and 5 scale. Singleton Birch would like to reproduce this.
I've been to Singleton Birch. SPAB organized a tour last year round their quarries and kilns and we had some very imformative talks from their technical people. Two of the very few English quarries where there is limestone with naturally hydraulic properties are here in Lincolnshire. That's what Singleton Birch are using. They hope to increase their production of hydraulic limes over the next couple of years, investing millions in a dedicated kiln.
Although most period building used just hydrated lime it is thought that much of London's 18th and 19th century housing used a lime that was very feebly hydraulic - maybe a '1' on the normal 2. 3.5 and 5 scale. Singleton Birch would like to reproduce this.
biffvernon
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Well Frank, I wouldn't have used NHL5 lime, but that doesn't explain why yours leaks. It really shouldn't. If it's leaking round the windows that might be because there's a crack where the mortar meets the wood. Sand/oil mastic avoids that problem because it sticks firmly yet flexibly to the timber in a way that lime mortar sometimes doesn't.
As for chasing round the country after sand, I really think the period approach is try to stick to materials that don't require lorries. Just dig up you own sand or, failing that, get whatever the nearest quarry supplies.
Reduce aggregate miles.
As for chasing round the country after sand, I really think the period approach is try to stick to materials that don't require lorries. Just dig up you own sand or, failing that, get whatever the nearest quarry supplies.
Reduce aggregate miles.
Michael wrote:
The label on the bag proclaiming it to be Singleton Birch Hydraulic Lime is the label telling you what you have purchased.
The Safety Data Label informing you that the bag contains Calcium Hydroxide Ca(OH)2 Hydrated Lime is telling you that if you get it on your skin or in your eyes then it's the Ca(OH)2 that is burning you and not the impurities within the lime which give it its hydraulic properties.
As for the sand to use 3 parts sharp to one part lime should be fine.
The label on the bag proclaiming it to be Singleton Birch Hydraulic Lime is the label telling you what you have purchased.
The Safety Data Label informing you that the bag contains Calcium Hydroxide Ca(OH)2 Hydrated Lime is telling you that if you get it on your skin or in your eyes then it's the Ca(OH)2 that is burning you and not the impurities within the lime which give it its hydraulic properties.
As for the sand to use 3 parts sharp to one part lime should be fine.
Nemesis
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Using NHL5 seems a bit OTT mind.