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Default Lime or cement mortar?

Lime or cement mortar?


This is specific to old buildings, and walls of similar construction.
These houses typically use soft bricks that break easily, often have
little in the way of foundations, sometimes none, and most have no dpc.



Movement
--------

Skimpy foundations mean minor movement is a normal event for many old
houses.

Cement is not movement friendly, and with any wall movement cement
typically makes a single clean break. It has no self healing ability.
Normal wall movement thus results in broken walls, which compromise the
overall house structure, and require extra repair work.

Cement mortar is stronger than soft brick, so when movement occurs it
is the bricks that will break rather than the cement. Broken bricks
have their core exposed, and without the protection of the fireskin
these bricks will usually begin to slowly deteriorate due to wet freeze
cycles. Gradual erosion of the brick leaves the wall in need of many
bricks being replaced. Its a shame to see walls like this, knowing that
just a little more knowledge and no damage would have occurred. Theres
a building near here that has about half the bricks near ground level
badly decayed, and is now in need of large numbers of bricks replaced.

Lime mortar is weaker than the soft bricks, so when movement occurs it
is the lime that cracks, not the bricks. This is the better option. No
bricks need replacement.

When moved to breaking point, instead of forming a single break, lime
tends to form lots of microcracks. Lime then reacts with the CO2 in the
air to grow hard crystals across these microcracks, and thus rebonds
itself. It self-heals. Lime mortar is not flexible, but it behaves as
if it were in this way. Lime accomodates normal minor movement without
incident.


Damp
----

Old houses handle damp differently to new builds. Soft bricks are
porous, and rain hitting them soaks in a little. Interior condensation
can also be a source of dampness in walls. Old buildings handle these
sources of damp by evaporation, which, if all is well, keeps the level
of damp below the point where any problems can occur.

Impurities or salts sometimes have to be got rid of as well as water.

Cement does not give much evaporation, and does not draw water from the
bricks, so with cement mortar almost all evaporation occurs through the
brick face. The problem is with salts: salt deposit crystals break the
faces of soft bricks. When this happens, the brick loses its protective
fireskin and begins to slowly disintegrate due to wet freeze cycles.

Lime mortar evporates water, and draws water from the bricks. This
saves the bricks from damage. When salt depositing occurs, the lime
mortar sacrifices itself instead, and any mortar damage is dealt with
by repointing on a normal timescale. No extra work is required and no
damage occurs.

The greater evaporation of lime also means a drier wall, and less
chance of damp problems.


Brick damage
------------

As well as the causes of brick damage above, cement adds one more. When
cement eventually breaks up and detaches from soft brick (or stone) at
the end of its life, it frequently pulls the skin off the brick with it
along the edges. This causes rounding of the brick edges, with the red
core exposed. It doesnt look good, and it is the start of slow
deterioration of the bricks due to wet freeze cycles. Over decades
cement work can do great damage to such walls. In the worst cases this
eventually leads to the need to rebuild with new bricks.

Lime does not cause this problem, and the wall stays in good health.


Environment
-----------

Lime requires lower temperatures and less energy to produce than
cement.

Used lime is chalk, a normal component of soil, thus use of lime leaves
no ecological footprint behind, causes no environmental waste problems,
and needs no disposal. Cement OTOH is a harmless bulk that needs to be
disposed of. Landfill is in limited supply, and causes its own eco
issues.

Lime sets by reacting with CO2 in the air, and is manufactured by
reversing this reaction using heat. The chemical cycle of lime is thus
CO2 neutral.


Workability
-----------

Lime is slow setting, meaning a single batch can be used as long as you
like. If you need to store it until tomorrow, this can be done by
putting it in an airtight container. In centuries past all the lime
used in a house may have been made in a single mix, and buried on site.
It stayed there throughout the construction, being used as needed. Lime
only sets when exposed to air.

Lime is much fatter than cement, making it nicer/easier to work with,
and reducing waste snots.


Cost
----

Hydrated bagged lime is around £6 a bag, cement around £3 a bag. The
lime bag however is larger as its lower density.

Lime is usually used as 3:1 mix by volume of sand to lime putty. (Lime
putty is lime mixed with water to a paste and stored.) It can also be
used straight from the bag as a 3:1 mix.

Bagged lime expands when water is added to make it putty, but by how
much I dont remember. Due to the various uncertain factors I dont know
which is cheaper, but I expect the initial cost difference is either
none or small.

Victorian properties with their original lime ceilings are still the
norm. They may be getting tatty but the fact that theyre usually still
there after 100-200 years says a lot. I dont have any hard data on life
expectancy of lime vs cement, but given this I expect lime may last
longer, and thus work out cheaper and less hassle in the long term.


Appearance
----------

Cement is a nice ugly heavy grey.

Lime is white, and lime mortar takes on the colour of the sand used to
some extent. Golden sand makes white mortar, red sand makes pale pink
mortar. In its most basic form lime mortar looks prettier, but it also
gives scope for further decoration. It is simple to include aggregate
to get black flecks in white mortar, or any other colour stone fleck.
Also lime mortar can be dyed any colour if wanted, since it starts out
white.

FWIW there are also various other materials that can be included in
lime mortar such as crushed bricks, tiles, cinders, shingle and so on,
all of which produce a decorative effect. While these can be included
in cement mortars as well, the heavy cement colour covers them and
makes them non-attractive.

Lime weathers by slow wear. This means it very gradually sheds its
surface over the years. This means surface dirt is carried away over
time. This self cleaning effect is very slow, but in any given
situation lime will end up less dirty than cement after many years.


g'nite

NT

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Default Lime or cement mortar?

Lime or cement mortar?

Congrats on a cracking post :-)

PS: any ideas whether lime mortar is suitable for repointing a
cemented wall ?
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Colin Wilson wrote:

Any ideas whether lime mortar is suitable for repointing a cemented wall ?


You can use it but it isn't as likely to stay in place.

The colour of the sand used in cement mortar controls the colour of the
mortar and the strength of the mix controls the damage it is likely to
do.

If using soft bricks you would use an eight to one mix -which at the
price given in the OP (and the quantities of lime needed as three to
one) makes it a far cheaper alternative. It is with the overall concern
of the project and the consumer's tastes that the costs may seem small.

It isn't in the same category for example as the price of a new car
compared to a three year old one. You can of course use any inert
admixture to either sand or cement to make mortar. And you can get a
pleasant effect with different sands if shortly after the bricks are
pointed, the wall is washed.

Maching it all the way through the different courses would require some
skill though. Too many would-be bricklayers can't even put a wall up
without a great variety of shade in the allegedly same mix.

Errors to watch out for are bricks laid upside down and the poor
selection of bricks by the labourer. Each course must be laid with a
few bricks from each pallet to prevent the differences in batches
showing up.

Also a load of bricks should never be tipped out of a lorry. This isn't
so much a problem these days with most lorries transporting them having
grabs.

Too frequently the developer will not have all the bricks for an house
delivered on site in one or two loads. Often this is a space or
security limitation.

And these days most labourers have little or no training, with
bricklayers on pricework not caring nor being paid to point out tips in
such craftsmanship.

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Default Lime or cement mortar?

Tiptop post on lime - and very much my practice.

My process for small quantities of lime putty - buy a new plastic
dustbin with tight fitting lid, half fill with water, empty a bag of
hydrated (builders) lime into it, leave for as long as possible
(ideally months).

I make up lime mortar when needed, half fill bucket with SHARP sand,
add a third more to the volume of lime putty by eye - mix with paddle
attachment on big drill, then keep bucket in binbag for ready supply-
as you say, it keeps so long as it's wet.

Might be worth saying a bit about mixing - as lime mortar is so
senstive to water content - the difference between a stiff mixture and
soup may be half a cup of water in a bucket. Often the moisture in the
sand plus the lime putty is just about the right water content - but if
the sand is a bit dry, getting that easy to work with softish butter
may take a little added water - go very gently to avoid ending up with
soup!

Would the OP like to add a bit about using hydraulic lime?



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wrote:
Lime or cement mortar?


This is specific to old buildings, and walls of similar construction.
These houses typically use soft bricks that break easily, often have
little in the way of foundations, sometimes none, and most have no dpc.



Movement
--------

Skimpy foundations mean minor movement is a normal event for many old
houses.

Cement is not movement friendly, and with any wall movement cement
typically makes a single clean break. It has no self healing ability.
Normal wall movement thus results in broken walls, which compromise the
overall house structure, and require extra repair work.

Cement mortar is stronger than soft brick, so when movement occurs it
is the bricks that will break rather than the cement. Broken bricks
have their core exposed, and without the protection of the fireskin
these bricks will usually begin to slowly deteriorate due to wet freeze
cycles. Gradual erosion of the brick leaves the wall in need of many
bricks being replaced. Its a shame to see walls like this, knowing that
just a little more knowledge and no damage would have occurred. Theres
a building near here that has about half the bricks near ground level
badly decayed, and is now in need of large numbers of bricks replaced.

Lime mortar is weaker than the soft bricks, so when movement occurs it
is the lime that cracks, not the bricks. This is the better option. No
bricks need replacement.

When moved to breaking point, instead of forming a single break, lime
tends to form lots of microcracks. Lime then reacts with the CO2 in the
air to grow hard crystals across these microcracks, and thus rebonds
itself. It self-heals. Lime mortar is not flexible, but it behaves as
if it were in this way. Lime accomodates normal minor movement without
incident.


Damp
----

Old houses handle damp differently to new builds. Soft bricks are
porous, and rain hitting them soaks in a little. Interior condensation
can also be a source of dampness in walls. Old buildings handle these
sources of damp by evaporation, which, if all is well, keeps the level
of damp below the point where any problems can occur.

Impurities or salts sometimes have to be got rid of as well as water.

Cement does not give much evaporation, and does not draw water from the
bricks, so with cement mortar almost all evaporation occurs through the
brick face. The problem is with salts: salt deposit crystals break the
faces of soft bricks. When this happens, the brick loses its protective
fireskin and begins to slowly disintegrate due to wet freeze cycles.

Lime mortar evporates water, and draws water from the bricks. This
saves the bricks from damage. When salt depositing occurs, the lime
mortar sacrifices itself instead, and any mortar damage is dealt with
by repointing on a normal timescale. No extra work is required and no
damage occurs.

The greater evaporation of lime also means a drier wall, and less
chance of damp problems.


Brick damage
------------

As well as the causes of brick damage above, cement adds one more. When
cement eventually breaks up and detaches from soft brick (or stone) at
the end of its life, it frequently pulls the skin off the brick with it
along the edges. This causes rounding of the brick edges, with the red
core exposed. It doesnt look good, and it is the start of slow
deterioration of the bricks due to wet freeze cycles. Over decades
cement work can do great damage to such walls. In the worst cases this
eventually leads to the need to rebuild with new bricks.

Lime does not cause this problem, and the wall stays in good health.


Environment
-----------

Lime requires lower temperatures and less energy to produce than
cement.

Used lime is chalk, a normal component of soil, thus use of lime leaves
no ecological footprint behind, causes no environmental waste problems,
and needs no disposal. Cement OTOH is a harmless bulk that needs to be
disposed of. Landfill is in limited supply, and causes its own eco
issues.

Lime sets by reacting with CO2 in the air, and is manufactured by
reversing this reaction using heat. The chemical cycle of lime is thus
CO2 neutral.


Workability
-----------

Lime is slow setting, meaning a single batch can be used as long as you
like. If you need to store it until tomorrow, this can be done by
putting it in an airtight container. In centuries past all the lime
used in a house may have been made in a single mix, and buried on site.
It stayed there throughout the construction, being used as needed. Lime
only sets when exposed to air.

Lime is much fatter than cement, making it nicer/easier to work with,
and reducing waste snots.


Cost
----

Hydrated bagged lime is around £6 a bag, cement around £3 a bag. The
lime bag however is larger as its lower density.

Lime is usually used as 3:1 mix by volume of sand to lime putty. (Lime
putty is lime mixed with water to a paste and stored.) It can also be
used straight from the bag as a 3:1 mix.

Bagged lime expands when water is added to make it putty, but by how
much I dont remember. Due to the various uncertain factors I dont know
which is cheaper, but I expect the initial cost difference is either
none or small.

Victorian properties with their original lime ceilings are still the
norm. They may be getting tatty but the fact that theyre usually still
there after 100-200 years says a lot. I dont have any hard data on life
expectancy of lime vs cement, but given this I expect lime may last
longer, and thus work out cheaper and less hassle in the long term.


Appearance
----------

Cement is a nice ugly heavy grey.

Lime is white, and lime mortar takes on the colour of the sand used to
some extent. Golden sand makes white mortar, red sand makes pale pink
mortar. In its most basic form lime mortar looks prettier, but it also
gives scope for further decoration. It is simple to include aggregate
to get black flecks in white mortar, or any other colour stone fleck.
Also lime mortar can be dyed any colour if wanted, since it starts out
white.

FWIW there are also various other materials that can be included in
lime mortar such as crushed bricks, tiles, cinders, shingle and so on,
all of which produce a decorative effect. While these can be included
in cement mortars as well, the heavy cement colour covers them and
makes them non-attractive.

Lime weathers by slow wear. This means it very gradually sheds its
surface over the years. This means surface dirt is carried away over
time. This self cleaning effect is very slow, but in any given
situation lime will end up less dirty than cement after many years.


g'nite

NT

Yeah, lime is so bloody marvellous that when they built the London sewer
they scraped it entirely in favour of Portland cement, which has stood
the test of time underground in the damp.

I won;t bother to go through pickling out the things that are plain
wrong, and those that are simply exaggerated through prejudice.

Suffice to say there are good reasons why Portland cement is used rather
than lime, these days.

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The Natural Philosopher wrote:

Yeah, lime is so bloody marvellous that when they built the London sewer
they scraped it entirely in favour of Portland cement, which has stood
the test of time underground in the damp.


The great advantage of portland cement is that it undergoes a very
predictable/repeatable chemical set, and it's fast - making it more
suitable for modern site bricklaying practice. For the same reasons
large quantities of concrete can be cast with highly consistent
properties.

I won;t bother to go through pickling out the things that are plain
wrong, and those that are simply exaggerated through prejudice.


Oh please do.

Suffice to say there are good reasons why Portland cement is used rather
than lime, these days.


Any others than the 2 I've mentioned above?

For the DIY'er with a slower work rate on buildings originally
constructed with lime mortar, there really isn't a downside. It's
easier to use, it can be kept indefinitely and it's better for the
building - and especially with soft bricks or limestone, it's a
necessity.

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Martin Bonner wrote:
The Natural Philosopher wrote:
wrote:
Lime or cement mortar?

I won't bother to go through pickling out the things that are plain
wrong, and those that are simply exaggerated through prejudice.


PLEASE do. Most of the OP seemed very reasonable to me, but I would
love to hear opposing views. (I have to say that the paens of praise
for the visual appearance of lime mortar struck me as over-egging the
pudding).

Suffice to say there are good reasons why Portland cement is used rather
than lime, these days.

To be fair, the OP did start:
This is specific to old buildings, and walls of similar construction.

With a new build, hard-fired bricks, DPC, and extensive foundations, a
lot of the arguments for lime go away.


As someone has already said, there is no mention of hydraulic lime. For
example, brick dust acts as a pozzolan (as does any material that has
previously been baked, volcanic ash, iron oxide dyes etc.) and this
causes the mortar to set in varying degrees. This aspect seems to be
shrouded in mystery (I suspect deliberately). How much of the alleged
self healing property is lost, and how does it then differ from cement?
I doubt the Victorians could build houses at the rate they did without
some form of set taking place.

IME, if you can't protect ordinary lime mortar from the weather, shallow
applications such as pointing will be washed away by the first rainfall.
Hanging damp sacks all over the place doesn't seem that practical to me.

The other issue is the degree to which modern additives have improved
the properties of cement. At a basic level I'm sure we're all familiar
with how pva reduces cracking and doubtless there are more sophisticated
products around.

There is of course a large element of brown eggs and bicycles about all
this too. Right on types who want to turn the whole thing into an art
form and congratulate each other on their good taste via various
conservation websites.



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I have to say that the paens of praise
for the visual appearance of lime mortar struck me as over-egging the
pudding


To me that's quite a plus. When repointing, you wait for an initial
set, then give it a going over with a stiff brush. Result is an
appearance very close to undamaged areas and is very forgiving of skill
levels - uniform consistant results for all of us.

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Stuart Noble wrote:
Martin Bonner wrote:
The Natural Philosopher wrote:
wrote:
Lime or cement mortar?
I won't bother to go through pickling out the things that are plain
wrong, and those that are simply exaggerated through prejudice.


PLEASE do. Most of the OP seemed very reasonable to me, but I would
love to hear opposing views. (I have to say that the paens of praise
for the visual appearance of lime mortar struck me as over-egging the
pudding).

Suffice to say there are good reasons why Portland cement is used rather
than lime, these days.

To be fair, the OP did start:
This is specific to old buildings, and walls of similar construction.

With a new build, hard-fired bricks, DPC, and extensive foundations, a
lot of the arguments for lime go away.


As someone has already said, there is no mention of hydraulic lime. For
example, brick dust acts as a pozzolan (as does any material that has
previously been baked, volcanic ash, iron oxide dyes etc.) and this
causes the mortar to set in varying degrees.


This aspect seems to be shrouded in mystery. How much of the alleged
self healing property is lost, and how does it then differ from cement?
I doubt the Victorians could build houses at the rate they did without
some form of set taking place.

IME, if you can't protect ordinary lime mortar from the weather, shallow
applications such as pointing will be washed away by the first rainfall.
Hanging damp sacks all over the place doesn't seem that practical to me.

The other issue is the degree to which modern additives have improved
the properties of cement. At a basic level I'm sure we're all familiar
with how pva reduces cracking and doubtless there are more sophisticated
products around.

There is of course a large element of brown eggs and bicycles about all
this too. Right on types who want to turn the whole thing into an art
form and congratulate each other on their good taste via various
conservation websites.


What a silly post.

The OP was discusing the use of limes as a compound best suited for
soft bricks.

As it happens the Romans who were responsible for the building of
sewers in the first century, built with concrete materials. I don't
know if that came from Pozzolan but it sounds suspiciously like it may
have:

Materials which enable lime mortars to set more rapidly include ash and
brick dust. Known as 'pozzolans' after the volcanic additives used by
the Romans, these materials are widely found in the lime mortars used
in old buildings and monuments.

Where conservation work is required, new mortars ought to match these
mortars, not only to ensure continuity with the past, but also to
ensure that the new work is both visually and physically compatible
with the old. It is therefore important that we know more about the
performance of these additives.

A simple everyday definition of 'pozzolan' could be 'a finely powdered
material which can be added to lime mortar (or to Portland cement
mortar) to increase durability and, in the case of lime mortars, to
provide a positive set'.

A more formal definition is given by ASTM C618 as 'a siliceous or
siliceous and aluminous material which, in itself, possesses little or
no cementitious value but which will, in finely divided form in the
presence of moisture, react chemically with calcium hydroxide at
ordinary temperature to form compounds possessing cementitious
properties'.

http://www.buildingconservation.com/...ozzo/pozzo.htm

The sewers built in Britain were not built until the Victorian era for
precisely that reason. Cement is a far better material to use such
places. As the bricks were of the very finest available, capable of
withstanding traffic in the world's busiest cities, you can see that
they chose well.

As for the Victorians building houses quickly; to build the sewers they
removed thousands of squalid hosuese and dug trenches by the mile in
which the sewers were laid. They then had gangs upon gangs putting the
housing on top of them.

I the eras befor modern planning laws it was very easy to use skilled
with semiskilled men to get the most out of both.

Such a situation is recurring these days now that there are no
apprentices growing into the trades. But that is a topic for
alt.politics.thatcherism.

***

One can use lime mortar in modern facework. Just remember to close the
gaps up. If you look at some of the fines examples of redbrick face
work still standing after a cetury or so, you may notice that they too
used lime mortar but that the distances between bricks are a lot
smaller than the present standards.

But the OP was not discussing modern standards you damn fool.

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The OP was discusing the use of limes as a compound best suited for
soft bricks.

As usual the OP wasn't *discussing* anything, just delivering another
sermon.
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On Thu, 10 Aug 2006 17:19:13 -0700, meow2222 wrote:


Environment
-----------

....
Lime sets by reacting with CO2 in the air, and is manufactured by
reversing this reaction using heat. The chemical cycle of lime is thus
CO2 neutral.


Only in respect of the CO2 used in the reaction: if production takes heat
then that will probably involve CO2 release (unless there are solar lime
kilns? :-))

I undersdood cement production was particularly energy-intensive. Anyone
know how much (or at lease how it compares with lime)?

And what is cement anyway? I thought it was at least related to lime.

Workability
-----------

Lime is slow setting, meaning a single batch can be used as long as you
like. If you need to store it until tomorrow, this can be done by
putting it in an airtight container. In centuries past all the lime
used in a house may have been made in a single mix, and buried on site.
It stayed there throughout the construction, being used as needed. Lime
only sets when exposed to air.


I remember finding a trough of mortar outside a building site on a sunday
evening. Assuming it had been left there some time I dipped my toe in it
to feel how hard it had set. It hadn't: it was soft and workable.
Presumably some sort of additive that made it keep for days? (I'm guessing
it was a cement mortar: this was in central London, not Briansville[1]

Lime is much fatter than cement, making it nicer/easier to work with,
and reducing waste snots.


What does fatter mean (in this context)?


Victorian properties with their original lime ceilings are still the
norm. They may be getting tatty but the fact that theyre usually still
there after 100-200 years says a lot. I dont have any hard data on life
expectancy of lime vs cement, but given this I expect lime may last
longer, and thus work out cheaper and less hassle in the long term.


Have there ever been cement ceilings? I thought the alternative to lime
plaster (and laths) was plasterboard.



Appearance
----------

Cement is a nice ugly heavy grey.


Nice ugly?!!




[1] Poundland? Poundbury? The new town/village on HRH's organic eco estate



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wrote:
Lime or cement mortar?



Phew, lot of feedback on this one! I guess there is a fair bit to
discuss. Maybe in time we could put together an FAQ on it, once we've
talked about the many points raised.

There is a whole lot to write about lime, and I'm not trying for a
book. Just wanted to put the hydrated lime mortar topic up here for us
to discuss, as its one thing I havent really seen addressed much here,
it is a question that comes up fairly regularly, and we dont seem to
have any real concensus so far, and no FAQ on it AFAIK.

So I can add a few more points to the discussion...


Re adding lime to cement mortars, this doesnt give any of the
properties of a lime mortar. Also most lime/cement mixes are liable to
fail prematurely, so adding a bit of lime to cement mortar or adding a
bit of cement to lime mortar are both not recommended. There has been
research done on this.


The chemical cycle of cement, I dont know that much about it, only that
its made from lime and clay, and takes a lot more heating energy to
produce than lime.


Re higher transport costs for lime putty, 2 points. First, transport
costs for ready mixed cement mortars will presumably be similar.
Second, I'm doubtful that transporting lime putty is likely to become a
significant part of building repair practice. As far as I can see it
seems to be an excessively priced product with no real need. Bagged
hydrated lime is a fraction of the price, and the logical option.


How lime mortar is fatter: Cement mortars are sand plus a thin liquid
with very little adhesion while wet. Lime has more stickiness, so the
mortar holds together better during working, and is easier to mould
into shapes that will keep their position. Hence less chance of snots
and waste.


Re lime and cement ceilings, there are plenty of cement ceilings
around, either cast in situ or fibre cement board. In time we'll see
how long they last, but possibly judging lime life by ceiling life is
unfair in that Victorian lime ceilings are normally supported by very
thin laths and nails and hung on flexible joists, quite unlike their
cast cement counterparts. And it is these lath supports failing that is
often the cause of lime ceilings starting to break, and that cant
fairly be blamed on the lime itself.


Re rain after application, last time I used lime outdoors it rained
when I was done and not a drop was washed away. (This was lime paint
not mortar.) I turned the hose on a little bit of it and found only a
pressurised jet (finger over hose end) would remove it, so its
vulnerable at first to heavy rain, but it was fine in the more common
light rain. I think the usual advice is check the forecast, and dont
use it before rain. One of its downsides, which I didnt really get into
the first time.


There are various lime mortar additives for use when the mortar
properties need modification. Examples are pozzolans, stone, hair &
other fibres, and linseed. There is also black mortar, and when my
brain returns I may remember whats in it. I think there are others that
get used too.


As usual the OP wasn't *discussing* anything, just delivering another sermon.


You can join in the discussion if you have something to add, or not,
upto you. Not much point just whimpering.


NT

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John Stumbles wrote:
On Thu, 10 Aug 2006 17:19:13 -0700, meow2222 wrote:

Lime sets by reacting with CO2 in the air, and is manufactured by
reversing this reaction using heat. The chemical cycle of lime is thus
CO2 neutral.


Only in respect of the CO2 used in the reaction: if production takes heat
then that will probably involve CO2 release (unless there are solar lime kilns?


All power is solar power is it not? Or did God create fossil fuels out
of nothing?

I undersdood cement production was particularly energy-intensive. Anyone
know how much (or at lease how it compares with lime)?


But modern plants use residues that can otherwise be a niusance to get
rid of. (Old tyres for example.)

I remember finding a trough of mortar outside a building site on a sunday
evening. Assuming it had been left there some time I dipped my toe in it
to feel how hard it had set. It hadn't: it was soft and workable.
Presumably some sort of additive that made it keep for days?


An additive is put in the mixture so that tubs of it can be stored on
site. It is ideal in confined conditions and saves a labourer or two.
The problem is that the people who make it can sometimes send out a
poorly co-ordinated set of batches.

That and it might be crap. I wouldn't know.

Lime is much fatter than cement, making it nicer/easier to work with,
and reducing waste snots.


What does fatter mean (in this context)?


It means spreadability. The stuff is splodgy. Wet sand is workable as
long as you keep it aereated that means continuallyt stirring it. When
it is fatty it can be left standing for ages.

Victorian properties with their original lime ceilings are still the
norm. They may be getting tatty but the fact that theyre usually still
there after 100-200 years says a lot. I dont have any hard data on life
expectancy of lime vs cement, but given this I expect lime may last
longer, and thus work out cheaper and less hassle in the long term.


Have there ever been cement ceilings? I thought the alternative to lime
plaster (and laths) was plasterboard.


I know that plasterboard has been in use for 40 to 50 years or more.
Which about the same time finishing plaster was sold in bags the way it
is now. Prior to that ceilings were a bugger to do. And they had to be
done using reinforced mortar.

I imagine that cement mortar would set too quickly for the facilities
available in those days and of course - before. Cement or lime, the
process was a real bugger to do with all the laths nailed at 14 or 16
inch centres.

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Weatherlawyer wrote:
John Stumbles wrote:


Have there ever been cement ceilings? I thought the alternative to lime
plaster (and laths) was plasterboard.


I know that plasterboard has been in use for 40 to 50 years or more.
Which about the same time finishing plaster was sold in bags the way it
is now. Prior to that ceilings were a bugger to do. And they had to be
done using reinforced mortar.


When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.


NT

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wrote in message

When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.



LOL
That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.



-


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As usual the OP wasn't *discussing* anything, just delivering another sermon.


You can join in the discussion if you have something to add, or not,
upto you. Not much point just whimpering.

I have raised the issue of pozzolans (yet again) and to what extent they
reduce the self healing properties. By whimpering I guess you mean
daring to question


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Mark wrote:
wrote in message

When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.



LOL
That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.


No these were relatively soft, unlike asbestos cement which is very
hard. Could be dented with fingernails. I've seen these boards
occasionally but dont know exactly what theyre called.


NT

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Tim Lamb wrote:
In message .com,
writes
So I can add a few more points to the discussion...


Re adding lime to cement mortars, this doesnt give any of the
properties of a lime mortar. Also most lime/cement mixes are liable to
fail prematurely, so adding a bit of lime to cement mortar or adding a
bit of cement to lime mortar are both not recommended. There has been
research done on this.


Oh.

When this farmhouse was rebuilt, the builders added a couple of shovels
of lime to the mix to *whiten* the end result. The bricks are somewhere
between soft and hard with normal foundations. Ten years on, the mortar
is still sound:-) Not a good match for exposed bits of Victorian stuff
as it is slightly yellow but much better than the khaki colour of my
masonry mix garage.

There is plenty of chalk locally and also grey river clay. I don't know
what the original builders used but it has visible chunks of chalk as
though through improper crushing. The chimney mortar was still soft and
very similar to river clay.

I note that Rugby masonry cement currently contains *fly ash* and that
the concrete floor recommendation included *slag cement* as a retarder.

regards


I thought they still used sugar as a retarder. Jim'll Mix It etc
Anyway, to return to the lime discussion. If the uncarbonated lime in
Durham Cathedral has been protected from carbon dioxide by the
carbonated mortar on the surface, it suggests that lime is capable of
forming an airtight seal, which in turn suggests that the building would
be unable to breathe.....
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To the lime skeptics here, I suggest a little more trying it out.

For an investment of £5 for a bag of builders lime you can experiment
for yourselves (and pound for a bucket, pound for some sharp sand - if
you don't have them lying about).

Find out for yourselves how easy it is to work with, experiment with
mixes, find out how long different sized lumps take to form a first and
second set and to gain most of it's strength.

And if you're not happy, you can rake it out again much more easily
than cement.

(and if you are, you have the rest ready to use in a covered bucket).



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On Sat, 12 Aug 2006 01:36:14 -0700, meow2222 wrote:

Mark wrote:
wrote in message

When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.


That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.


No these were relatively soft, unlike asbestos cement which is very
hard. Could be dented with fingernails. I've seen these boards
occasionally but dont know exactly what theyre called.


Must check my mum's bathroom when I'm up there in the next few weeks -
she's got panels about 2-3' square with strips of wood about 2-3" wide
edging them, in a 1920s-1930s house. I just thought it was a feature.

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The message
from "Mark" contains these words:

When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.


LOL
That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.


One of my rooms has a ceiling like that although the board in question
is neither plaster nor asbestos but fibre.

--
Roger Chapman
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In article ,
Tim Lamb writes:
When this farmhouse was rebuilt, the builders added a couple of shovels
of lime to the mix to *whiten* the end result.


You can buy white cement, if you are just concerned about colour
matching (probably need to go to a good builder's merchant.
Sand can have a lot of pigment in it too -- that varies enormously.

--
Andrew Gabriel
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On Fri, 11 Aug 2006 13:58:29 -0700, Weatherlawyer wrote:

All power is solar power is it not?


So where did the sun get its energy?

Or did God create fossil fuels out
of nothing?


Well if God can be created out of nothing, why not?



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Ooooh goodie an opportunity to wibble about lime ...

Cost
----

Hydrated bagged lime is around =A36 a bag, cement around =A33 a bag. The
lime bag however is larger as its lower density.

Lime is usually used as 3:1 mix by volume of sand to lime putty. (Lime
putty is lime mixed with water to a paste and stored.) It can also be
used straight from the bag as a 3:1 mix.


For some jobs

Dunno which jobs tho cos I wouldnt do this - bricklaying perhaps? Dont
risk it for external rendering

Bagged lime expands when water is added to make it putty, but by how
much I dont remember. Due to the various uncertain factors I dont know
which is cheaper, but I expect the initial cost difference is either
none or small.


Homemade putty with bagged lime is much cheaper than bought putty

Victorian properties with their original lime ceilings are still the
norm. They may be getting tatty but the fact that theyre usually still
there after 100-200 years says a lot. I dont have any hard data on life
expectancy of lime vs cement, but given this I expect lime may last
longer, and thus work out cheaper and less hassle in the long term.


Labour costs are higher with lime cos more tending is needed due to
slower setting time and also cos there is a shortage of good lime
plasterers so they charge more

=========

I make up lime mortar when needed, half fill bucket with SHARP sand,


Better to use a well graded sand. My supplier sells it as 'plastering
sand'. For rendering I would try 3 sharp to 1 soft sand as a
substitute for well graded sand (um never have needed to tho ...) For
bricklaying a softer mix is better

==========

eah, lime is so bloody marvellous that when they built the London sewer
hey scraped it entirely in favour of Portland cement, which has stood
he test of time underground in the damp.


TNP playing devils advocate again I see

Cement based mortars are better in continually damp stuations

There is a spectrum of products

Lime putty mortar
Weak hydraulic lime mortar
Strong hydraulic lime mortar
Cement mortar (concrete)

and you should choose the one appropriate to the situation, bearing in
mind that big business has been promoting the concrete and strong
hydraulic lime end of the spectrum for many years

============

Hanging damp sacks all over the place doesn't seem that practical to me.


Its not. I use hessian sheeting

=============

One can use lime mortar in modern facework. Just remember to close the
gaps up. If you look at some of the fines examples of redbrick face
work still standing after a cetury or so, you may notice that they too
used lime mortar but that the distances between bricks are a lot
smaller than the present standards.


With lime you dont need to leave expansion joints so it looks more
aesthetically pleasing

=============

What's the "chemical cycle" of cement?


Difference of cement to lime putty is more impurities (silicon mostly)
and higher temperature of production

Lime putty cycle is:

Chalk or limestone + heat
Drives off CO2 and H20, producing quicklime (dangerous!)
Add H2O to produce lime putty
Take it out of the tub and put it on the wall
Add CO2 from the air and it becomes chemically equivalent to limestone
/ chalk once again

The cement cycle is the same with added twiddles

What about the production cycle? How much CO2 is released in processing
and transporting v. cement?


Processing lime uses less CO2 cos it is not cooked so much.
Transportation of lime uses more CO2 because there are less economies
of scale, unless you make your own quicklime (and loads of enthusiasts
do)

==========

What does fatter mean (in this context)?


More workable, user friendly. Cement mortar often has lime added
simply to make it fatter. Cement + Lime + sand is a cement mortar not
a lime mortar. These days FebXXX often gets used instead of lime

============

Have there ever been cement ceilings? I thought the alternative to lime
plaster (and laths) was plasterboard.


There we open up another can of worms. Lime mortar used to be used
both indoors and out. Nowadays cement mortar is used outdoors and
gypsum mortar / plasterboard is used indoors

===========

Re adding lime to cement mortars, this doesnt give any of the
properties of a lime mortar. Also most lime/cement mixes are liable to
fail prematurely, so adding a bit of lime to cement mortar or adding a
bit of cement to lime mortar are both not recommended. There has been
research done on this.


Lime mortar with no cement sets OK
Cement mortar with no lime sets OK
Cement mortar with a little lime as a plasticiser sets OK
Lime mortar with a little cement added 'to help it set' may not set OK

Cement is very fine, fills up the pores in the mortar, CO2 cant get to
the lime so poor lime set. Not much cement so poor cement set and the
result is a poorly set mortar

Sadly many good and experienced builders do not know this. They know
lots about concrete but lime mortar is very poorly understood

================

Anna

~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
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On Sat, 12 Aug 2006 07:34:54 GMT, Stuart Noble
wrote:

I have raised the issue of pozzolans (yet again) and to what extent they
reduce the self healing properties. By whimpering I guess you mean
daring to question


Yes it does reduce the self healing properties but by how much i dont
know

=========

Maybe you could spray it with soda water to accelerate the initial set.


Joke not - It has been done! It works fine but the clients start
lookig suspicious

=========

Anna
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
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John Stumbles wrote:
On Fri, 11 Aug 2006 13:58:29 -0700, Weatherlawyer wrote:

Well if God can be created out of nothing, why not?


What makes you think that he did?

The bible says he "hung it upon nothing" and that he "created it not
for nothing". I don't remember a quote from that source implying he
made it "out of nothing".

Notwithstanding wild guesses about cosmogeny, I was actually asking you
where the oil came from. Not that I don't already know. I was just
wondering how circular your reasoning could get around to.

Not that I don't already know, of course.

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wrote in message
oups.com...
Mark wrote:
wrote in message

When PB came out it had a coarser surface than todays and was nailed

in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever

possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.



LOL
That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.


No these were relatively soft, unlike asbestos cement which is very
hard. Could be dented with fingernails. I've seen these boards
occasionally but dont know exactly what theyre called.


That would be fibreboard but personally I have only seen that used for
ceilings in cheep council houses.
Reading anyone ?



-

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Anna Kettle wrote:
On Sat, 12 Aug 2006 07:34:54 GMT, Stuart Noble
wrote:


Maybe you could spray it with soda water to accelerate the initial set.


Joke not - It has been done! It works fine but the clients start
lookig suspicious


ISTR a thread about making motrar with soda water for quicker set, and
I tihnk someone calculated that the amount of CO2 would be a drop in
the ocean of what the lime will use as it sets. But maybe it provides a
little head start.

NT



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Anna Kettle wrote:
Ooooh goodie an opportunity to wibble about lime ...


Lime putty is sometimes made from quicklime (producing warm mortar),
but usually its slaked to produce hydrated lime, distributed, then
water is addded again to produce the putty.


NT

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Anna Kettle wrote:

Re adding lime to cement mortars, this doesnt give any of the
properties of a lime mortar. Also most lime/cement mixes are liable to
fail prematurely, so adding a bit of lime to cement mortar or adding a
bit of cement to lime mortar are both not recommended. There has been
research done on this.


Lime mortar with no cement sets OK
Cement mortar with no lime sets OK
Cement mortar with a little lime as a plasticiser sets OK
Lime mortar with a little cement added 'to help it set' may not set OK

Cement is very fine, fills up the pores in the mortar, CO2 cant get to
the lime so poor lime set. Not much cement so poor cement set and the
result is a poorly set mortar

Sadly many good and experienced builders do not know this. They know
lots about concrete but lime mortar is very poorly understood


Cement properties are rarely understood, there is no doubt a loss of
quality control between research laboratories and bricklayers who have
been working for decades. Both think they know it all. Een so clled
experts tend to overlook the types of cements.

That quick setting stuff that used to be used in precast huge
structures such as swimming pool beams and motorway bridges for
example, took everyone by surprise.

I wonder if a little lime might have supported things a bit better.

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Anna Kettle wrote:
On Sat, 12 Aug 2006 07:34:54 GMT, Stuart Noble
wrote:

I have raised the issue of pozzolans (yet again) and to what extent they
reduce the self healing properties. By whimpering I guess you mean
daring to question


Yes it does reduce the self healing properties but by how much i dont
know

=========

Maybe you could spray it with soda water to accelerate the initial set.


Joke not - It has been done! It works fine but the clients start
lookig suspicious


How about dry ice?
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Weatherlawyer wrote:

Cement properties are rarely understood, there is no doubt a loss of
quality control between research laboratories and bricklayers who have
been working for decades. Both think they know it all. Een so clled
experts tend to overlook the types of cements.

That quick setting stuff that used to be used in precast huge
structures such as swimming pool beams and motorway bridges for
example, took everyone by surprise.

I wonder if a little lime might have supported things a bit better.


Where can we read more about types of cement? IIRC theres opc, hac,
sulphate resisting, weld cement, no doubt more too.


NT

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wrote:

Where can we read more about types of cement? IIRC theres opc, hac,
sulphate resisting, weld cement, no doubt more too.


In recent years, the market for packed cement products has become much
more sophisticated. New standards have introduced the opportunity to
develop more durable cements to meet the needs of the market.

To align our product offering with the needs of the end user an
extensive national research programme was carried out. The research was
carried out during 2004 and 2005 and covered hundreds of interviews,
focus groups, usage and attitude surveys and conjoint analysis with
merchants and end users including product demonstrations and selection
processes.

The results of the study together with further investigation of which
products should be included in our packed cement range of choices have
led to our '3 cement product range'.
http://www.lafargecement.co.uk
http://www.lafargecement.co.uk/defau...skipCheck=true

Portland cement is the most common type of cement in general usage, as
it is a basic ingredient of concrete, mortar and most non-speciality
grout. It is a finely-ground powder produced by grinding Portland
cement clinker (more than 90%), about a maximum of 5% gypsum which
controls the set time and up to 5% minor constituents (as allowed by
various standards).

As defined by the European Standard EN197.1, Portland cement clinker is
a hydraulic material which shall consist of at least two-thirds by mass
of Calcium silicates (3CaO.SiO2 and 2CaO,SiO2), the remainder
consisting of aluminium- and iron-containing clinker phases and other
compounds.

The ratio of (CaO/SiO2) shall not be less than 2.0. The magnesium
content (MgO) shall not exceed 5.0% by mass. (the last two requirements
were already set out in the German Standard, issued in 1909).

Portland cement clinker is made by heating, in a kiln unit, an
homogenous mixture of raw materials to a sintering temperature, which
is about 1450°C for modern cements.

The aluminium oxide and iron oxide are present as a flux and contribute
little to the strength properties of Portland cement. For special
cements, such as Low Heat (LH) and Sulfate Resistance (SR), it is
necessary to limit the amount of tricalcium aluminate (3CaO.Al2O3)
formed.

The major raw material for the clinker-making is limestone (CaCO3).
Normally, an impure limestone which contains SiO2 is used - the CaCO3
content can be as low as 80%.

Secondary raw materials depend on the purity of the limestone. Some of
the secondary raw materials used a sand, shale, iron ore, bauxite,
fly ash and slag. When a kiln is fired by coal, the ash of the coal
becomes a secondary raw material.

In the 19th and early 20th century, clay was a common secondary raw
material, particulary in the wet process which is no longer used. In
the 21st century, it would be rare for clay to be used in a raw mix,
because it gives handling problems and contributes unnecessary
aluminium oxide.

Cement plants as alternatives to conventional waste disposal or
processing

Due to the high temperatures inside the cement kilns, combined with the
oxidizing (oxygen-rich) atmosphere and long residence times, it has
proven to be an excellent processing option for various types of waste
streams. The waste streams often contain combustible material which
allows the substitution of part of the fossil fuel normally used in the
process.

Waste materials used in cement kilns as a fuel supplement: [8]

1. Car and truck tires; steel belts are easily tolerated in the
kilns
2. Waste solvents and lubricants.
3. Hazardous waste; cement kilns completely destroy hazardous
organic compounds
4. Bone meal; slaughter house waste due to bovine spongiform
encephalopathy contamination concerns (in Europe)
5. Waste plastics
6. Sewage sludge
7. Rice shells
8. Sugar cane waste

Industrial by-products used as a raw material:

1. Blastfurnace slag (granulated, water quenched)
2. Fly ash (from power plants)
3. Silica fume (from steel mills)
4. Synthetic gypsum (from desulfurization)
http://en.wikipedia.org/wiki/Portland_cement

Fly ash is the finely divided mineral residue resulting from the
combustion of powdered coal in electric generating plants. Fly ash
consists of inorganic, incombustible matter present in the coal that
has been fused during combustion into a glassy, amorphous structure.
Coal can range in ash content from 2%-30%, and of this around 85%
becomes fly ash. (The remaining 15% is called bottom ash and isn't
lifted up by the flue gases.)

Fly ash material is solidified while suspended in the exhaust gases and
is collected by electrostatic precipitators or filter bags. Since the
particles solidify while suspended in the exhaust gases, fly ash
particles are generally spherical in shape and range in size from 0.5
µm to 100 µm.

They consist mostly of silicon dioxide (SiO2), aluminium oxide (Al2O3)
and iron oxide (Fe2O3), and are hence a suitable source of aluminum and
silicon for geopolymers. They are also pozzolanic in nature and react
with calcium hydroxide and alkali to form cementitious compounds. Fly
ash also contains some heavy metals.
http://en.wikipedia.org/wiki/Fly_ash

Some pie in the sky about asphalt replacing cement in roads:
http://technology.guardian.co.uk/wee...771589,00.html

(I thought that was a substance alreay in use.)

((And anyway transport costs could be decimated (maybe even
cementimated) with the use of neither, if more canals were made using
clay as the waterproof liner the way that they were made 200 years or
so back. That would cut out modern water problems too; as well as
supplying drought stricken areas, the creation of more and larger
canals would be the creation of resevoirs at the same time.))

Then there are geopolymers:
http://www.geopolymer.org/

Thinking about that ancient process reminds me of the silly ideas our
scientific monkeys have about ancient copper and lead mines in this
archipelago. I suspected that there must have been some sort of
crushing machine at the brochs and other long lost mining sites. And
why would they not also be utilised in the production of lime, cement
and pottery as well as ore milling?

Digging huge caverns with bones and antlers. As if!
http://www.orkneyjar.com/history/brochs/index.html

Slipping slightly off topic:

Ray Mears in one of his survival programmes, remarked that ancient
Britons consumed vast quantities of shelfish at the water's edge. That
we know this from the vast heaps of shells from the eaten fish that
have been found and dated to the long ago.

Thinking about that concept leads me to believe how unlikely it is.
Just supposing a clan held togehter long enough to consume that amount
actually at the beach or riverside - even over a period of years, makes
me wonder why they saw fit to collect the residue togehter in neat
stacks.

You just wouldn't do it. First of because the tribe would just
gravitate to a newer harvest site. Secondly the waste heaps would stink
and thirdly, the chances of their waste being piled in places that they
would survive intact for all time at, is ridiculous.

The piles were obviously stored in a secure location from the tide and
the weather. But what for? I had supposed for fertilising acid clay
soils. But also they would have been part og the lime cache that these
brochs would have crushed.

(Yes I know that the full use of the ancient buildings remains unknown.
But the DO seem like windmills to me.)

And slipping further still:

Several semi historical shows on the TV have attempted to demonstrate
how a blacksmith might have produced an iron sword. OK the method of
welding red hot iron bars byt smiting them together on an anvil is the
most likely way of doing it.

But with wind or water power the ancients could have drop forged a
sword in a couple of smacks with a hammer lifted by a powered axle.
Likewise a coin would have been fairly easy to mint.

And the same process would have been used -maybe the same mill, if they
wanted to crush ore or baked clay as well as pulverise limestone or
shell. Of course the transportable and least durable pars of a mill
would not survive the centuries. But somewhere in the mud of copper
producing regions, there may yet be found some preserved centreposts.
Who can say?

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