Schoolmarm
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Aha, that is a bit clearer. :lol:
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FamilyWiggs
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Back of the net!
Cash back!
and of course
Butter my arse!
Cash back!
and of course
Butter my arse!
This argument has been raging for years and if I had a quid for every time I've heard it dragged up I'd be posting from a yacht in the carribean and my tools would be rusting on the bottom of the sea!
Let me try and simplify it.
Bagged hydrate is no good on it's own for mortar,it's used in colleges because it can be crushed and mixed again,as they do in a pan roller mixer.
In fact any lime mortar can be crushed and used again,but ONLY as aggregate,more lime,putty or hydraulic must be added.
Technically lime putty and bagged hydrate are the same,the latter being slaked with just enough water to create a powder,putty being slaked with water to create well....putty!
It doesn't matter how fresh hydrated lime is,as soon as it's hydrated it's exposed to air and carbonization begins and continues in the bag,that's what the little lumps are you find in every bag no matter how fresh.
The only thing hydrate is really any good for is as a plasticiser by adding a small amount to hydraulic mortars,there have been arguments about that too over the years and opinions constantly change but you can and I do add hydrate or even a little putty to hydraulic mortars to fatten them up(waiting for the incoming on that one!)
The only other time I would use hydrated lime is in tuck pointing,not that I've done much of it,but the way I was shown to do that about ten years ago was with lime so fresh you hydrated it yourself.
We took quicklime and added just enough water to get the powder,sieved it then mixed with boiled linseed oil and silver sand,whether that's how it was done traditionally I don't know,it was the result of research by two friends of mine,a historic buildings consultant and lime mortar/putty producer,and a structural engineer specialising in historic buildings.
My personal favourite mortar to use is a putty mix,I much prefer it over hydraulic mortars.
It's not true that lime mortars have no strength,remember,in masonry it's use to keep the bricks apart,not stick them together,and I've come across lime mortars harder than modern cement mortars,one job in particular it was easy to rake out the cement pointing but everything bounced off the lime underneath,the house was built in 1530 but this particular wall was built around 300 years ago and a pozzolan was used.
As for a 70's build having a crumbly,sandy mortar it's not uncommon I'm afraid,to skimp on costs OPC mixes as weak as 9:1:1 were used,I even saw a spec for 11:1:1,these were sometimes pointed over with a harder mortar.
Now,without wishing to cause offence to anyone one of the most common queries from my website is "How do I do this?",so I tell them,and the most common reply is,"But I've been told to do it this way!"
So my most common reply now is"If you already know why are you asking me?"
There are no experts in this game,only those who think they are.
I only have a rough idea what I'm doing,the largest project I ever took on in lime was maybe a couple of million bricks.
If you look at my website(ignore the wording,the lady who runs it substitutes my wording for hers!)you'll see in the top right hand corner a twin roundel oast house,it's part of a seven building Georgian farm complex that was in the way of the channel tunnel rail link and moved,the granary I built on my own,the oast was the second building where I got a couple of apprentices from the local college and my old boss to help out.
All built in lime putty(hydraulic in the footings,no cement,no concrete)
Now I prefer smaller projects and when I can find the photos I'll update the site and the blog.
Back to Pauls original topic,if he has live/blown areas of plaster it's because as I said no suction due to the paint residue,lime isn't like modern plasters that stick like the proverbial to a blanket.
You could use casein as an adhesive but I've never tried it in plaster or render,only for deep grouting in stonework and wouldn't recommend it.
I already know the next question,why does lime render stick so well to non porous masonry like flint?
Dunno,but if you look at many Norman Churches it still does in places.
And my view is it adheres to the mortar.
I've laid flint but never rendered over so never had a chance to experiment.
Paul,you will have to take off the blown areas and repair,the cracks are normal on a base/scratch coat but that coat is the most important and what holds the whole lot on the wall,any failure will make subsequent coats fail.
None of us get it right first time :wink:
Let me try and simplify it.
Bagged hydrate is no good on it's own for mortar,it's used in colleges because it can be crushed and mixed again,as they do in a pan roller mixer.
In fact any lime mortar can be crushed and used again,but ONLY as aggregate,more lime,putty or hydraulic must be added.
Technically lime putty and bagged hydrate are the same,the latter being slaked with just enough water to create a powder,putty being slaked with water to create well....putty!
It doesn't matter how fresh hydrated lime is,as soon as it's hydrated it's exposed to air and carbonization begins and continues in the bag,that's what the little lumps are you find in every bag no matter how fresh.
The only thing hydrate is really any good for is as a plasticiser by adding a small amount to hydraulic mortars,there have been arguments about that too over the years and opinions constantly change but you can and I do add hydrate or even a little putty to hydraulic mortars to fatten them up(waiting for the incoming on that one!)
The only other time I would use hydrated lime is in tuck pointing,not that I've done much of it,but the way I was shown to do that about ten years ago was with lime so fresh you hydrated it yourself.
We took quicklime and added just enough water to get the powder,sieved it then mixed with boiled linseed oil and silver sand,whether that's how it was done traditionally I don't know,it was the result of research by two friends of mine,a historic buildings consultant and lime mortar/putty producer,and a structural engineer specialising in historic buildings.
My personal favourite mortar to use is a putty mix,I much prefer it over hydraulic mortars.
It's not true that lime mortars have no strength,remember,in masonry it's use to keep the bricks apart,not stick them together,and I've come across lime mortars harder than modern cement mortars,one job in particular it was easy to rake out the cement pointing but everything bounced off the lime underneath,the house was built in 1530 but this particular wall was built around 300 years ago and a pozzolan was used.
As for a 70's build having a crumbly,sandy mortar it's not uncommon I'm afraid,to skimp on costs OPC mixes as weak as 9:1:1 were used,I even saw a spec for 11:1:1,these were sometimes pointed over with a harder mortar.
Now,without wishing to cause offence to anyone one of the most common queries from my website is "How do I do this?",so I tell them,and the most common reply is,"But I've been told to do it this way!"
So my most common reply now is"If you already know why are you asking me?"
Maybe they have my dear but it doesn't make it right.
There are no experts in this game,only those who think they are.
I only have a rough idea what I'm doing,the largest project I ever took on in lime was maybe a couple of million bricks.
If you look at my website(ignore the wording,the lady who runs it substitutes my wording for hers!)you'll see in the top right hand corner a twin roundel oast house,it's part of a seven building Georgian farm complex that was in the way of the channel tunnel rail link and moved,the granary I built on my own,the oast was the second building where I got a couple of apprentices from the local college and my old boss to help out.
All built in lime putty(hydraulic in the footings,no cement,no concrete)
Now I prefer smaller projects and when I can find the photos I'll update the site and the blog.
Back to Pauls original topic,if he has live/blown areas of plaster it's because as I said no suction due to the paint residue,lime isn't like modern plasters that stick like the proverbial to a blanket.
You could use casein as an adhesive but I've never tried it in plaster or render,only for deep grouting in stonework and wouldn't recommend it.
I already know the next question,why does lime render stick so well to non porous masonry like flint?
Dunno,but if you look at many Norman Churches it still does in places.
And my view is it adheres to the mortar.
I've laid flint but never rendered over so never had a chance to experiment.
Paul,you will have to take off the blown areas and repair,the cracks are normal on a base/scratch coat but that coat is the most important and what holds the whole lot on the wall,any failure will make subsequent coats fail.
None of us get it right first time :wink:
JoceAndChris
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Andy- it is indeed fascinating to read your posts, and I hope you'll stay with us and continue to share that wonderful experience.
FamilyWiggs
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Andy - a great website. I'd encourage everyone here to click the link on the right and read it. Your passion and committment to preserving old buildings shines through strongly - if only there were more like you. Looking forward to it being completed with more pics and projects!
Loved the blog too - traditional buildings and traditional sausagemaking; what a perfect mix! Looking forward to making our own sausages, bacon and hams once "Wiggs Pigs" arrive... a day which is creeping ever closer...
Loved the blog too - traditional buildings and traditional sausagemaking; what a perfect mix! Looking forward to making our own sausages, bacon and hams once "Wiggs Pigs" arrive... a day which is creeping ever closer...
Thanks and comments appreciated.
I am a total(well almost)novice at making sausages but trust me they are good
Put it this way,I can live off the contents of my freezer for the next month or two sausage wise :lol:
Bacon I need to do,I've got a couple of older clients with inglenooks I'm hoping to convince to smoke a lump of belly pork for me for streaky,just hang it up in the chimney.
Hams I'm not going to get into,it's out of my league and I don't like the chemical cures a lot of people use so curing ham is way beyond me at the moment but I am working on a home made smoker that will be a bit of a Heath Robinson device :shock:
Sausages I'm totally bonkers about so watch that space!
I've got some plans for new kit.
I'm not such a novice on lime mortar though :wink:
I really need to update the site
This thread appears to have been hijacked :mrgreen:
I am a total(well almost)novice at making sausages but trust me they are good
Put it this way,I can live off the contents of my freezer for the next month or two sausage wise :lol:
Bacon I need to do,I've got a couple of older clients with inglenooks I'm hoping to convince to smoke a lump of belly pork for me for streaky,just hang it up in the chimney.
Hams I'm not going to get into,it's out of my league and I don't like the chemical cures a lot of people use so curing ham is way beyond me at the moment but I am working on a home made smoker that will be a bit of a Heath Robinson device :shock:
Sausages I'm totally bonkers about so watch that space!
I've got some plans for new kit.
I'm not such a novice on lime mortar though :wink:
I really need to update the site
This thread appears to have been hijacked :mrgreen:
Thanks for the replies all, seemed to drift off topic a bit but has now returned
On the first picture it looks worse than it was when we eventually plastered, the residue is actually cement from where we hacked off the plaster/render applied when the house was "renovated" in the '80's. I managed to brush most of this off as it was quite powdery.
Some of the other walls are quite uneven and we have had to dub these out prior to applying the scratch coat.
I will chop out the small areas that seem not to have taken, but will use a wetter mix - noted the idea about using lime water, i have been doing that as well using the excess left over from some tubs of lime putty.
A couple of walls I have done over the weekend I used a less stiff mix on and these seem to be working better with less shrinkage and no detatchment (yet) so I think the original problem might have been more to do with how dry the mix was.
Experience comes with practice and advice so here goes for the next round
Paul.
On the first picture it looks worse than it was when we eventually plastered, the residue is actually cement from where we hacked off the plaster/render applied when the house was "renovated" in the '80's. I managed to brush most of this off as it was quite powdery.
Some of the other walls are quite uneven and we have had to dub these out prior to applying the scratch coat.
I will chop out the small areas that seem not to have taken, but will use a wetter mix - noted the idea about using lime water, i have been doing that as well using the excess left over from some tubs of lime putty.
A couple of walls I have done over the weekend I used a less stiff mix on and these seem to be working better with less shrinkage and no detatchment (yet) so I think the original problem might have been more to do with how dry the mix was.
Experience comes with practice and advice so here goes for the next round
Paul.
I don't think you have caused any offence. It is these sorts of conversations that raise the issues that amateurs like myself learn from. We can then pass on this knowledge when appropriate.OddJob said:
As you are aware, an awful lot of knowledge has been lost in using materials such as lime and some people have picked up some weird ideas. As somebody that wishes to learn, this makes it difficult for me to know who is right and hence all the questions as to why something should be done in a particular way. As an engineer, the why is very important as it allows me to make a judgement as to which random stranger I should believe when it comes to a process or procedure. Don't get me wrong, I've no problem with somebody saying "I don't know why it is done that way, it always has been and all my mates in the trade do it that way as well and nothing has fallen down yet". That statement tells us that the reasons for doing a process one particular way, may have been lost but it is very likely to be a good way to do it. On the other hand, if somebody comes along later and says that "it isn't a good way because of X, Y & Z and this person has tested it and found that this other way is better because.." then we can make a judgement on that. As an example, 6:1:1 mixes are fine if you want a strong mix but 3:1 lime mixes with a couple of handfuls of cement are a bad idea as the cement clumps making the mix weaker than without it. How do I know this? well somebody has tested it and the results are published.
Back to the hydrate / putty question:
I agree with you here, (apart from the lumps which I've never noticed) however, the question is "how quickly does it carbonate in the bag?" I do not know the answer to this (and would be interested in knowing it) blue circle give a lifetime of 3 months+ for their hydrate and I know that my local builders merchants gets a new pallet of hydrate every two weeks. I would therefore expect a bag of hydrate used within a month to have very similar active lime levels to that of putty. Any unused lime should be converted into putty of course for it to keep. Exactly the same process applies to NHL limes which will also carbonate in the bag. Some lime producers state that they will keep for 1 year in the bag so again the process must be slow.
From this, I conclude that there is no technical reason not to use hydrate. In my very limited experience have also not noticed any difference in workability between hydrate and putty and as hydrate is cheaper, unless given a good reason not to, I will continue to use it. I very much welcome comments on this.
Totally agree for most construction where everything is being kept in compression. It is where some of the structure could be in tension (such as long thin walls) that you have to worry. As we all know, cement will stick bricks together, so can be used to form structures which lime should not be.OddJob said:
I've tried to look up some figures as the tensile and compressive strengths of cement and lime mortars and couldn't find anything quickly. My memory tells me that lime is weaker than cement in compression (though this normally isn't a problem), that cement is poor in tension compared to compression and that lime is awful in tension compared to compression. If anybody has a table of figures then this would be useful to know.
Interestingly, whilst looking for figures for the above, I came across this: http://www.springerlink.com/content/t15n6743774k1p15/
I, like most people here I guess, would have said that NHL 5 is stronger than NHL 2 (indeed the number refers to its compressive strength). However, this document shows that other factors (such as water content) are more important when it comes to tensile strength. This document also suggests that my statement above about lime being awful in tension compared to cement is also not necessarily correct. More research needed when I have time.
Okay,let's try and start from the top but chances are I'll answer the questions not in order,I do suggest you read this though.
http://www.amazon.co.uk/Building-Lime-Introduction-Stafford-Holmes/dp/1853395471
I don't know where my copy is so can't quote.
I'd also suggest this discussion be moved to a separate thread as it's hijacking Pauls original query.
As an engineer you should be aware that old buildings are subject to four forces,
Stress
Compression
Tension
Shear
You should know which does what.
I'm not an engineer,I stick to what I know.
And you should be old enough not to believe what random strangers tell you.
Trouble is does it work for the house 30 years down the line?
I give a lifetime guarantee,meaning it won't fall down in my lifetime
I work on buildings 500-600 years old,they're still standing,unlike many that were built in the last 50-60 years.
Now,the people who constructed those old buildings all those centuries ago.
Did they have access to overpaid surveyors,engineers,architects and mad theorists that create problems where they don't exist?
No of course they didn't,it's the above that fubar them with ignorance and modern ideas.
As the old saying goes,
"If it ain't broke don't fix it".
So why do all these tests?
Because engineers never believe they are wrong until they have to put the bits they lost or broke back together and by that time it's too bloody late!
You said it yourself.
Why not just leave it alone and not fiddle about with it?
And who tested it?
Wasn't that Tommy off the telly was it :roll:
April fools day is long gone mate!
As soon as it's hydrated.
You choose who you want to believe,a builders merchant who sells cement and the salary men at Blue Circle,neither of whom would know how to use lime if it climbed up their company uniform trousers and bit them on the nadgers.
Or a lime practicioner.
Your choice.
I think I just broke some ribs laughing.
But no,the numbers do not apply to its compressive strength.
They refer to the natural impurities in the lime,i.e. clay that aids setting.
Hydraulic limes compressive strength is a different matter altogether and will depend on aggregates used and other agents.
Some use a pozzolan even with hydraulic.
I tell everyone I try to help out with lime the same thing.
It ain't rocket science,it's common sense.
Now back in the day they didn't have rocket science.............
Andy
http://www.amazon.co.uk/Building-Lime-Introduction-Stafford-Holmes/dp/1853395471
I don't know where my copy is so can't quote.
I'd also suggest this discussion be moved to a separate thread as it's hijacking Pauls original query.
As an engineer you should be aware that old buildings are subject to four forces,
Stress
Compression
Tension
Shear
You should know which does what.
I'm not an engineer,I stick to what I know.
And you should be old enough not to believe what random strangers tell you.
That's the excuse used by people who have either never used lime or don't want to,they've only used cement and it works perfectly well for them and gets the job done.
Trouble is does it work for the house 30 years down the line?
I give a lifetime guarantee,meaning it won't fall down in my lifetime
I work on buildings 500-600 years old,they're still standing,unlike many that were built in the last 50-60 years.
Now,the people who constructed those old buildings all those centuries ago.
Did they have access to overpaid surveyors,engineers,architects and mad theorists that create problems where they don't exist?
No of course they didn't,it's the above that fubar them with ignorance and modern ideas.
As the old saying goes,
"If it ain't broke don't fix it".
So why do all these tests?
Because engineers never believe they are wrong until they have to put the bits they lost or broke back together and by that time it's too bloody late!
You said it yourself.
Why?
Why not just leave it alone and not fiddle about with it?
I'd recheck that if I were you,published where exactly?
And who tested it?
Wasn't that Tommy off the telly was it :roll:
April fools day is long gone mate!
I thought I explained that,you obviously weren't paying attention.
As soon as it's hydrated.
You choose who you want to believe,a builders merchant who sells cement and the salary men at Blue Circle,neither of whom would know how to use lime if it climbed up their company uniform trousers and bit them on the nadgers.
Or a lime practicioner.
Your choice.
:lol:
I think I just broke some ribs laughing.
Yes NHL 5 is stronger than NHL 2,eminently versus feebly hydraulic,with NHL 3.5 being moderately hydraulic.
But no,the numbers do not apply to its compressive strength.
They refer to the natural impurities in the lime,i.e. clay that aids setting.
Hydraulic limes compressive strength is a different matter altogether and will depend on aggregates used and other agents.
Some use a pozzolan even with hydraulic.
I tell everyone I try to help out with lime the same thing.
It ain't rocket science,it's common sense.
Now back in the day they didn't have rocket science.............
Andy
Schoolmarm
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I'm so glad you have joined. 8)
Schoolmarm
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I am not a teacher really, but there are a few other members who are/were.
Do you ever do courses or instruction?
Do you ever do courses or instruction?
Gervase
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JoceAndChris
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Oh, oh oh that looks amazing. Thanks for letting us know this development in the business.
But what I really want is just to give Gervase a big stash of cash to just come here and fix my house. Tired of broken down fingernails.
But what I really want is just to give Gervase a big stash of cash to just come here and fix my house. Tired of broken down fingernails.
Schoolmarm
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OMG Gervase I didn't spot that when I was rummaging about on your website a couple of weeks ago!
I do onsite training/instruction mainly for homeowners but builders as well,I don't have the premises for running courses sadly.Schoolmarm said:
Paul,you mentioned the residue was cement,it struck me that maybe PVA was applied to the wall when it was rendered originally?
Or a damp proofer?
That would cause problems with the lime plaster bonding to the surface.
Could be, everything on the building has been bodged that I can see so nothing surprises me anymore , most of the plaster has bonded ok, its just some small patches that haven't taken so I will remove these and replaster and see how it goes.
I see you are in Hastings, we are along the south coast in Kent. If you ever have a job over this way ping me and I would be happy to buy you a beer or a coffee. Might be we need a bit of support with some of the bigger jobs as well so could be a worthwhile conversation.
Note on your web site you did some work on a bread oven, we have a dissused one in the farmhouse that I have toyed with re-instating, wondered what your work was that you did?
Paul.
, most of the plaster has bonded ok, its just some small patches that haven't taken so I will remove these and replaster and see how it goes.I see you are in Hastings, we are along the south coast in Kent. If you ever have a job over this way ping me and I would be happy to buy you a beer or a coffee. Might be we need a bit of support with some of the bigger jobs as well so could be a worthwhile conversation.
Note on your web site you did some work on a bread oven, we have a dissused one in the farmhouse that I have toyed with re-instating, wondered what your work was that you did?
Paul.
Gervase
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Gwan, gwan, gwan, you know you really want to! :wink:JoceAndChris said:
Schoolmarm
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I can't think of anyone better Joce than Gervase.