Exposed Cotswold Stone Wall Needs Sealing
Charlbury
Has anyone any experience or suggestions on what to use to seal an
exposed cotswold stone wall? I have read previous threads on using a
diluted PVA mixture and will probably go with this but I thought I
would see if anyone had actually done this on a cotswold stone wall.
Thanks
big...@meeow.co.uk
Why do you want to seal it? If its an old wall, sealing generally makes
them wetter, not drier, and is not at all recommended.
PVA certainly isnt suitable.
NT
Mike
"Charlbury" <st...@steveonthenet.com> wrote in message
news:1115643173.7...@f14g2000cwb.googlegroups.com...
> Hi
>
> Has anyone any experience or suggestions on what to use to seal an
> exposed cotswold stone wall?
It doesn't need sealing and doing so will cause severe problems in future.
If you are having problems it may be the pointing is failing though.
Stuart Noble
> It doesn't need sealing
>and doing so will cause severe problems in future.
Says who?
Don't you think it would be more constructive if you made some positive
suggestions?
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Stuart Noble
<big...@meeow.co.uk> wrote in message
>If its an old wall, sealing generally makes
> them wetter, not drier, and is not at all recommended.
Perhaps you can explain the logic of this. Not recommended by who?
> PVA certainly isnt suitable.
PVA isn't sufficiently waterproof. If the wall is already painted, try a
pliolite resin based paint. If not, copious amounts of Thomsons Waterseal
or
similar applied during a dry spell would be the best bet.
big...@meeow.co.uk
Mike:
> > It doesn't need sealing
> >and doing so will cause severe problems in future.
> Says who?
Mike. And the experts:
http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl
and SPAB
> Don't you think it would be more constructive if you made some
positive
> suggestions?
he just did.
NT
big...@meeow.co.uk
> <big...@meeow.co.uk> wrote in message
>
> >If its an old wall, sealing generally makes
> > them wetter, not drier, and is not at all recommended.
>
> Perhaps you can explain the logic of this. Not recommended by who?
No. Ask these guys if you want:
http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl
NT
mark
wrote:
PVA is quickly destroyed by UV exposure.
Stupid idea!
Anna Kettle
>Stuart Noble wrote:
>Mike:
>
>> > It doesn't need sealing
>> >and doing so will cause severe problems in future.
>
>> Says who?
Me, for one. There are two house building strategies.
The traditional strategy was used until 19somethingorother and uses
breatheable materials like lime plaster, stone, brick. Any water which
gets into the material evaporates off in its own sweet time
The modern strategy using damp courses and impermeable layers like
masonry paint, sand/cement render, PVA which don't allow any moisture
into the material.
If detailed properly, both of these systems work well, but problems
can occur when they are mixed up eg
Victorian brick building which has later been covered in sand cement
render on the outside and gypsum plaster on the inside. Moisture gets
in somehow, maybe cos the damp course is not of 21stC standard. The
moisture can't get out through the sand/cement render so it gets out
through the gypsum - which fails cos gypsum can't cope with getting
wet at all
Your exposed Cotswold stone wall would I assume have been built in the
traditional strategy and if you seal the surface with PVA or the like,
any moisture which gets into the wall will not be able to easily
escape and you will get problems like rising damp, bubbling and damp
patches
If you want to seal the wall because it is dusty, then I suggest you
make some limewater [1] and apply few thin coats. The stone will still
show through cos limewater is almost clear, but it will stop the
dusting
Anna
[1] Buy small tub of lime putty. Decant some into a larger tub with
plenty of water. Mix well. Allow to settle. Paint with resulting clear
liquid. Repeat until happy [2]
[2] Rumour has it that in hard water areas, painting with tapwater
will be just as effective
Anna
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
Pete C
wrote:
>Hi
Hi,
Why the need for sealing, is it suffering frost damage?
cheers,
Pete.
Stuart Noble
"Anna Kettle" <An...@kettlenet.co.uk> wrote in message >
> The traditional strategy was used until 19somethingorother and uses
> breatheable materials like lime plaster, stone, brick.
So bricks and stones breathe, but cement doesn't?
>Any water which
> gets into the material evaporates off in its own sweet time
After it's destroyed the Laura Ashley presumably. Damp is not trivial and
the fact that we don't tolerate it in modern buildings is a mark of
progress
IMO. People before buildings I think.
> impermeable layers like
> masonry paint, sand/cement render, PVA
None of these is impermeable to "moisture". We need to differentiate
between
water, as in rainfall, and water vapour which, being airborne, will travel
through virtually anything. The outside of a house needs to shed water
effectively but allow the passage of vapour which, fortunately, isn't that
difficult.
> Victorian brick building which has later been covered in sand cement
Usually in the hope of preventing damp.
> Moisture gets
> in somehow
It gets in because the render cracks and water can pour through at a rate
of
knots. Why it cracks is IMO because it didn't adhere to the surface in the
first place so it moves due to its own weight. Cracks invariably
correspond
to larger areas of blown render, though which came first is open to
debate.
>The
> moisture can't get out through the sand/cement render
Because a disproportionate amount gets through the cracks rather than the
impermeability of the cement.
Out of interest (and I really do mean that :-), what mix do you use for
your
pargetting? Do you use pozzolans?
Pipps Cottage looks great and I can see why restoration is high on your
agenda but trying to stop a brick built terraced house leaking like a
seive
is another matter.
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Stuart Noble
<big...@meeow.co.uk> wrote in message
news:1115686177....@o13g2000cwo.googlegroups.com...
> Stuart Noble wrote:
> Mike:
>
>> > It doesn't need sealing
>> >and doing so will cause severe problems in future.
>
>> Says who?
>
> Mike. And the experts:
> http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl
> and SPAB
Self appointed experts
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Stuart Noble
<big...@meeow.co.uk> wrote in message
news:1115686235....@o13g2000cwo.googlegroups.com...
I'm asking you. You're the one laying down the law.
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Anna Kettle
<stuart_no...@ntlworld.com> wrote:
>>Any water which
>> gets into the material evaporates off in its own sweet time
>
>After it's destroyed the Laura Ashley presumably. Damp is not trivial and
>the fact that we don't tolerate it in modern buildings is a mark of
>progress
>IMO. People before buildings I think.
I used to have a Victorian house and on the most exposed wall, no
emulsion paint or paper stayed good for more than a couple of years.
In hindsight I should have used limewash on that wall and kept the
Laura Ashley for the other three. There's no point fighting a losing
battle
>> impermeable layers like
>> masonry paint, sand/cement render, PVA
>
>None of these is impermeable to "moisture". We need to differentiate
>between
>water, as in rainfall, and water vapour which, being airborne, will travel
>through virtually anything. The outside of a house needs to shed water
>effectively but allow the passage of vapour which, fortunately, isn't that
>difficult.
PVA and masonry paint are effectively a layer of plastic so water
vapour can't get through them.
>> Victorian brick building which has later been covered in sand cement
>
>Usually in the hope of preventing damp
And usually unsuccessfully
>> Moisture gets
>> in somehow
>
>It gets in because the render cracks and water can pour through at a rate
>of
>knots. Why it cracks is IMO because it didn't adhere to the surface in the
>first place so it moves due to its own weight. Cracks invariably
>correspond
>to larger areas of blown render, though which came first is open to
>debate.
Agreed. And also cos the wall is built of brick and lime mortar which
will move slightly. Sand cement render is hard and brittle and doesn't
move, just cracks :(
>Out of interest (and I really do mean that :-), what mix do you use for
>your
>pargetting?
Often I use 3 parts chalk, 1 part lime putty plus goathair. Until
about 200 years ago chalk was used instead of sand around here. Why it
went out of fashion I don't know, but it makes a lovely malleable
mortar
>Do you use pozzolans?
Not much these days cos much of my work is on timber framed buildings
which move around with the seasons and pozzolans make the mortar more
brittle (and resistant to weathering). When I was working in wet and
stony Wales I used pozzolans much more
>Pips Cottage looks great and I can see why restoration is high on your
>agenda but trying to stop a brick built terraced house leaking like a
>seive is another matter.
Its the same matter actually cos both my timber frame and Victorian
terraces were built to breathe. Luckily I don't have a plastic
emulsion paint and Laura Ashley wallpaper lust. Pips Cottage has just
turned bright Suffolk pink but I won't post any new pictures until
I've painted black stripes on it so it looks just as wacky as it used
to do 100 years ago
Mike
<big...@meeow.co.uk> wrote in message
news:1115686177....@o13g2000cwo.googlegroups.com...
Thanks for the support. Actually the key people who I'd trust making this
recommendation are the RICS special interest group on old properties as they
see all the damage done by incorrect approaches.
My approach to old and listed buildings which I restore is simple - no
sealing with PVA or other materials.
Can anybody tell me why I can't see any of Stuart's postings directly ?
big...@meeow.co.uk
> "Anna Kettle" <An...@kettlenet.co.uk> wrote in message >
> > The traditional strategy was used until 19somethingorother and uses
> > breatheable materials like lime plaster, stone, brick.
>
> So bricks and stones breathe, but cement doesn't?
1:1:6 does a little, but not enough for Victorian brick walls, 3:1
doesnt. Chalk does, granite doesnt. So not that simple.
> >Any water which
> > gets into the material evaporates off in its own sweet time
>
> After it's destroyed the Laura Ashley presumably.
you presume wrong. Millions of Vic properties are dissipating their
moisture this way, and dissipating it quickly enough that no damage
occurs to the wallpaper etc.
> Damp is not trivial and
> the fact that we don't tolerate it in modern buildings is a mark of
> progress
> IMO.
Victorian houses were dry enough 100 years ago, as they are today. The
idea that houses were horribly damp a century ago is a popular
misconception. Of course there would have been worse houses around, but
of those still up today, most didnt have a problem. Some do now as a
result of inappropriate modern work.
> People before buildings I think.
>
> > impermeable layers like
> > masonry paint, sand/cement render, PVA
>
> None of these is impermeable to "moisture". We need to differentiate
> between
> water, as in rainfall, and water vapour which, being airborne, will
travel
> through virtually anything. The outside of a house needs to shed
water
> effectively but allow the passage of vapour which, fortunately, isn't
that
> difficult.
Cement render and gypsum allow vapour passage, but not enough.
I dont know why im writing this, you were given a good link and are
only being a wally.
> > Victorian brick building which has later been covered in sand
cement
>
> Usually in the hope of preventing damp.
>
> > Moisture gets
> > in somehow
>
> It gets in because the render cracks and water can pour through at a
rate
> of
> knots. Why it cracks is IMO because it didn't adhere to the surface
in the
> first place so it moves due to its own weight.
its one cause
> Cracks invariably
> correspond
> to larger areas of blown render,
not always. cracks here that arent connected with blown areas.
> though which came first is open to
> debate.
>
> >The
> > moisture can't get out through the sand/cement render
>
> Because a disproportionate amount gets through the cracks rather than
the
> impermeability of the cement.
>
> Out of interest (and I really do mean that :-), what mix do you use
for
> your
> pargetting? Do you use pozzolans?
> Pipps Cottage looks great and I can see why restoration is high on
your
> agenda but trying to stop a brick built terraced house leaking like
a
> seive
> is another matter.
Controlling damp in Vic teraces is not achieved by stopping them
leaking, in fact that is moving in the wrong direction altogether in
most cases.
NT
Stuart Noble
> I dont know why im writing this, you were given a good link and are
> only being a wally.
own
arses for my liking
> Controlling damp in Vic teraces is not achieved by stopping them
> leaking, in fact that is moving in the wrong direction altogether in
> most cases.
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Charlbury
(well almost any) chance of dust or debris from the wall onto work
surfaces.
Steve
Charlbury
Thanks!
bi...@biffvernon.freeserve.co.uk
"lime putty" and you may find one within striking distance. It usually
comes in 25litre tubs which is far more than you need but if you can
find a builder who understands how to care for old buildings he/she
will probably have some and let you have a small amount. Ring you
local Conservation Officer and ask if he knows anyone local that uses
it. As a last resort, you could use the hydrated lime that comes in
paper sacks at any builders' merchants. Put a cupful in a tub of
water, stir it up and leave for a day or two. Then use the resulting
lime putty in the way that Anna recommended.
Isn't it a shame that Stuart is so rude instead of being willing to
debate issues constructively. Some of us who use the Period Property
forum really do know rather a lot about their subjects and are more
than willing to share their experience. You won't find much enthusiasm
there for ever using Portland cement, gypsum plaster or any surface
covering that makes walls less 'breathable'.
big...@meeow.co.uk
I think what you need is a porous stabiliser. Sealing is not
recommended. I'm told lime water is good for this.
NT
big...@meeow.co.uk
> Isn't it a shame that Stuart is so rude instead of being willing to
> debate issues constructively. Some of us who use the Period Property
> forum really do know rather a lot about their subjects and are more
> than willing to share their experience.
... and are able to back up by citing the various expert bodies out
there, as well as explaining things in detail.
But you know what they say, a fool is one who calls the wise foolish,
and the foolish wise.
NT
Charlbury
I think I'll be going for a delivery of Lime Putty from these guys:
big...@meeow.co.uk
Well, dont pay more than £6.50 for it. A bag of lime from the local BM
can be mixed to putty and left to mature for a few weeks in a sealed
container.
NT
bi...@biffvernon.freeserve.co.uk
the wet way and left to mature. Hydrated lime from a bag will do for
some purposes but there are differences. Womersleys have a good
reputation for selling good stuff. BTW I notice a bag of hydrated lime
at Jewsons is about £3 more expensive than at B&Q. Hmmm.
Stuart Noble
<big...@meeow.co.uk> wrote in message
news:1116071043....@g14g2000cwa.googlegroups.com...
> b...@biffvernon.freeserve.co.uk wrote:
>
>> Isn't it a shame that Stuart is so rude instead of being willing to
>> debate issues constructively.
I'm perfectly willing to debate issues constructively but turning the
clock
back 100 years and refusing to budge doesn't constitute debate in my view.
And constant references to a website where people gather to congratulate
themselves on their good taste doesn't either.
Can *you* explain how lime can be made water resistant without losing the
properties which distinguish it from cement? Let's debate it!
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made water resistant without losing the properties which distinguish it
Lime, when used in mortar for brickwork, allows water to pass through
the bedding planes. This water can then evaporate, keeping the wall
dry and protecting bricks from damage. This is particularly important
when the bricks are relatively weak and/or the wall does not have a
damp proof course. Both factors apply in many old buildings. Using
Ordinary Portland Cement either in the bonding mortar or for repointing
inhibits this moisture flow and makes it more likely that the wall
remains damp. External damage to bricks and internal damage to
decorative finishes may result. OPC mortars are stronger and harder
than lime mortars so tend to crack if there are any movements in the
wall. This is particularly important in old buildings that were not
built on stiff concrete foundations. Lime mortars accommodate movement
by forming micro-cracks which then self-heal by recrystallization of
the calcite. A small amount of water moving through the wall helps
this process. Substanial and costly foundations and damp-proof courses
are usually not needed for lime mortar bonded walls. When used as an
internal wall plaster, lime allows the movement of water without
sustaining any damage. Gypsum plaster disintegrates when wetted as the
hydrous and anhydrous forms of the calcium sulphate crystals have
different volumes. Lime mortars and plasters are not damaged by water.
Gypsum plasters are popular in the modern building trade where the
plasterer likes a quick set. Three coats and home for tea and start on
another job tomorrow. Working with lime takes time but the results are
compatible with the proper functioning of an old building in which
moisture management is critical. The use of any waterproof membranes
and sealants tend to interfere with this and should usually be avoided.
There is a considerable literature on the subject and I would suggest
you start with Jane Schofield's little book about lime, available
through SPAB, the Society for the Protection of Ancient Buildings.
Lime mortars and plasters are now the materials of choice for most most
Conservation Officers, English Heritage, the National Trust and others
concerned with the care of buildings from before the early 20th
century.
There are also sound arguements on sustainability, cost and aesthetic
grounds, for using traditional materials such as lime, brick, timber
and linseed oil in new builds rather than Portland cement, steel,
gypsum and petroleum-based paints and sealants. As we move into the
era of oil depletion it may not be an option.
Stuart Noble
<bi...@biffvernon.freeserve.co.uk> wrote in message
news:1116230861....@z14g2000cwz.googlegroups.com...
> Stuart, I'm not quite sure what you mean by "explain how lime can be
> made water resistant without losing the properties which distinguish it
> from cement".
Well, I realise that you can use pozzolans to make lime set, but it then
takes on the undesirable properties of cement and loses its self healing
capabilities.
> Lime, when used in mortar for brickwork, allows water to pass through
> the bedding planes. This water can then evaporate, keeping the wall
> dry and protecting bricks from damage.
So in a 9" wall driving rain passes through the mortar and ends up where?
Does it evaporate to the inside?
>This is particularly important
> when the bricks are relatively weak and/or the wall does not have a
> damp proof course. Both factors apply in many old buildings. Using
> Ordinary Portland Cement either in the bonding mortar or for repointing
> inhibits this moisture flow and makes it more likely that the wall
> remains damp.
If cement stops water getting in, there isn't a probelm with it getting
out.
The wall doesn't get damp in the first place.
>External damage to bricks and internal damage to
> decorative finishes may result. OPC mortars are stronger and harder
> than lime mortars so tend to crack if there are any movements in the
> wall.
I can only say not in my experience. I have re-pointed loads of brickwork
with cement mortar but I have combined it with modern polymers. They do
not
affect the appearance but seem to give it added flexibility. Certainly
none
of it has cracked over 5-10 year periods.Without modification, sand cement
mortars do not reliably adhere to old brickwork.
>This is particularly important in old buildings that were not
> built on stiff concrete foundations. Lime mortars accommodate >movement
> by forming micro-cracks which then self-heal by recrystallization of
> the calcite. A small amount of water moving through the wall helps
> this process. Substanial and costly foundations and damp-proof courses
> are usually not needed for lime mortar bonded walls. When used as an
> internal wall plaster, lime allows the movement of water without
> sustaining any damage. Gypsum plaster disintegrates when wetted as the
> hydrous and anhydrous forms of the calcium sulphate crystals have
> different volumes. Lime mortars and plasters are not damaged by water.
But anything on the plaster will be damaged, which rules out wall
coverings.
> Gypsum plasters are popular in the modern building trade where the
> plasterer likes a quick set. Three coats and home for tea and start on
> another job tomorrow. Working with lime takes time but the results are
> compatible with the proper functioning of an old building in which
> moisture management is critical.
All very well but, in the real world, your average punter has to deal with
your average builder.
> There are also sound arguements on sustainability, cost and aesthetic
> grounds, for using traditional materials such as lime, brick, timber
> and linseed oil in new builds rather than Portland cement, steel,
> gypsum and petroleum-based paints and sealants. As we move into the
> era of oil depletion it may not be an option.
There are plenty of areas where modern materials can help with
conservation.
The Victorians couldn't have preserved the Mary Rose.
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then
takes on the undesirable properties of cement and loses its self
healing
capabilities.
special situations - lighthouses, bridge piers, maybe chimneys.
"So in a 9" wall driving rain passes through the mortar and ends up
where?
Does it evaporate to the inside?
more water moves in the other direction. Most of the damp in a house
comes from people breathing, cooking, washing and watering their
potplants. The problem is getting rid of all this water without it just
condensing on the wall and then spoing the decoration.
If cement stops water getting in, there isn't a probelm with it getting
out. The wall doesn't get damp in the first place.
Think of the house like a goretex jacket - a plastic mac keeps the rain
out but you get sweaty, a breathable fabric keeps the rain out and
keeps you dry inside when you perspire.
They do not affect the appearance
Personal taste is involved in aethetics but on a historic building you
would probably not get Listed Buildings Consent to repoint with OPC so
if you did use it you would be guilty of a criminal offence.
5-10 year periods
are a short time in the life of a building, or should be.
sand cement
mortars do not reliably adhere to old brickwork.
Often true, lime mortar is more reliable when correctly applied. On
the other hand, brickwork bonded with OPC mortar often sticks so firmly
to bricks that they cannot be cleaned it the building is ever
demolished. The bricks cannot then be reused easily. Old bricks with
lime mortar are easy to clean and given a new life in a new building or
a repair of ann old one.
But anything on the plaster will be damaged, which rules out wall
coverings
The damage is usually caused by water from inside condensing on the
inner surface of the wall. Water from outside is more likely to come
from damaged rainwater goods or soil accumulating against a wall at its
base rather than from rain wetting the wall's surface.
All very well but, in the real world, your average punter has to deal
with
your average builder.
How terribly true. We do have a great task in educating the building
industry.
There are plenty of areas where modern materials can help with
conservation.
The Victorians couldn't have preserved the Mary Rose.
Yes, and the use of resins and steels are invaluable in preserving
historic fabric where, for example, joist ends have rotted. I'm no
Luddite, but am interested in both caring for our heritage and building
sustainably for the future.
Mike
<bi...@biffvernon.freeserve.co.uk> wrote in message
news:1116241125.5...@f14g2000cwb.googlegroups.com...
> Yes, and the use of resins and steels are invaluable in preserving
> historic fabric where, for example, joist ends have rotted.
I was agreeing with everything you said wholeheartedly until you got to
this. I know a lot of people share your view but my counter argument is
that a failed joist should be removed and an exact copy made in the same
wood. Yes it will take many years for it to age enough to look the same but
my belief is that you have a more exact preservation of the original
building for those to come in the future and will require less work in
future to keep it so. Resin bonded joists could be a real pig to remove
when the time does come to replace them when they fail completely.
After all would you try to repair a failed brick or try to find a similar
one, preferably from that period ?
Anna Kettle
>then takes on the undesirable properties of cement and loses its self
>healing capabilities.
Pozzolans form very weak cements, like the early cements of 150 years
ago. Modern cements are about 20 times as strong
>"So in a 9" wall driving rain passes through the mortar and ends up
>where?
>Does it evaporate to the inside?
Driving rain hits the wall but only makes it through the first 1mm or
so, and then the surface layer is waterlogged and no more rain can get
in. Water vapour moves through the mortar much more freely
>If cement stops water getting in, there isn't a probelm with it getting
>out.
>The wall doesn't get damp in the first place.
Indeed that is true. But can you guarantee that water won't get in?
Especially on an old house without rigid foundations?
>I can only say not in my experience. I have re-pointed loads of brickwork
>with cement mortar but I have combined it with modern polymers
>They do not
>affect the appearance but seem to give it added flexibility. Certainly
>none
>of it has cracked over 5-10 year periods.Without modification, sand cement
>mortars do not reliably adhere to old brickwork.
Thats interesting. You mean Febmix or suchlike? Lime is sometimes used
as a plasticiser in cement render too. Do you think it is less
successful, or is Febmix just more convenient for you?
>But anything on the plaster will be damaged, which rules out wall
>coverings
Perhaps it is time for wallhangings to come back into fashion!
Charlbury
>We can let you have a 1 litre tub [of lime putty] for £1.50 plus VAT
and delivery. I >personally would not use this route. Although what
you have been told is correct, I use >silicate fixative to do a much
better job with no discolouration. Very breathable too.
>The only things to watch are, the silicate fixative is very caustic,
so don't get it on your >skin or in your eyes and you cannot use
limewash after using it.
Does anyone have any experience with this or a view on the suggestion?
Thanks again
Steve
Mike
<bi...@biffvernon.freeserve.co.uk> wrote in message
news:1116149799.1...@g43g2000cwa.googlegroups.com...
I would, and do, happily pay more than Ł6.50 for real lime putty made
the wet way and left to mature. Hydrated lime from a bag will do for
some purposes but there are differences. Womersleys have a good
reputation for selling good stuff. BTW I notice a bag of hydrated lime
The price of hydrated lime does appear quite random. I have a line of
plastic dustbins used to mature lime putty which I make from hydrated lime.
It needs several months for best result. I also get ready made putty from
Bleaklow (near Buxton - proper Buxton lime) just down the road but for most
applications there is little difference in the final result. I find the
choice of sand far more critical to a good or bad result and go far and wide
to look for better types. Three years ago Wickes sharp sand was superb but
then of course they changed quarry and couldn't/wouldn't tell me where they
used to get it.
bi...@biffvernon.freeserve.co.uk
example to illustrate that there may be some good uses for modern
materials. Not a very good example, on reflection. There are better
examples in Richard Oxley,. Survey and Repair of Traditional
Buildings: A Conservation and Sustainable Approach. Donhead 2003
There's some information about sodium silicate or waterglass and its
effects in cement here:
http://www.pqcorp.com/applications/cementsandconstructionmaterials_application.asp
and on nearby pages.
Stuart Noble
"Mike" <mi...@nospam.com> wrote in message
news:d6aici$a21$1...@newsg3.svr.pol.co.uk...
I don't think one should lose sight of the fact that houses are just
places
where people live. The rest is just fashion.
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Stuart Noble
>Most of the damp in a house
> comes from people breathing, cooking, washing and watering their
> potplants.
I don't really buy this. I've seem many examples where rain comes straight
through the wall summer or winter, which would seem to rule out
condensation.
> Think of the house like a goretex jacket - a plastic mac keeps the rain
> out but you get sweaty, a breathable fabric keeps the rain out and
> keeps you dry inside when you perspire.
Yes but nothing you can apply to the outside of a house is as effective as
a
plastic mac. Cement behaves like the goretex, keeping water droplets out
but
allowing vapour to pass outwards.
> Personal taste is involved in aethetics but on a historic building you
> would probably not get Listed Buildings Consent to repoint with OPC so
> if you did use it you would be guilty of a criminal offence.
I don't think the humble abodes I work on are likely to fall in that
category. Mostly people who just want to protect their families from damp.
>OPC mortar often sticks so firmly
> to bricks that they cannot be cleaned it the building is ever
> demolished. The bricks cannot then be reused easily. Old bricks with
> lime mortar are easy to clean and given a new life in a new building or
> a repair of ann old one.
This is all a bit nerdy isn't it? People first, conservation where
possible,
but not at any cost.
>> But anything on the plaster will be damaged, which rules out wall
>> coverings
> The damage is usually caused by water from inside condensing on the
> inner surface of the wall.
Now this simply isn't true. Most houses are centrally heated and have
adequate ventilation. If human activity produces condensation on the
walls,
then one or other must be lacking.
>Water from outside is more likely to come
> from damaged rainwater goods or soil accumulating against a wall at its
> base rather than from rain wetting the wall's surface.
On the odd occasion that's true. Mostly it's just driving rain hitting
porous walls.
>I'm no
> Luddite, but am interested in both caring for our heritage and building
> sustainably for the future.
IMO the restoration culture is essentially fuelled by money. What people
perceive as heritage fetches more money in the housing market.
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Stuart Noble
> >Well, I realise that you can use pozzolans to make lime set, but it
>>then takes on the undesirable properties of cement and loses its self
>>healing capabilities.
>
> Pozzolans form very weak cements, like the early cements of 150 years
> ago. Modern cements are about 20 times as strong
>
>>"So in a 9" wall driving rain passes through the mortar and ends up
>>where?
>>Does it evaporate to the inside?
>
> Driving rain hits the wall but only makes it through the first 1mm or
> so, and then the surface layer is waterlogged and no more rain can get
> in.
I wish I could believe that. I expect it's true in ideal conditions where
the overall depth of mortar is several inches but, in the realms of
patching
up old brickwork, the thickness is likely to be less than an inch. IME
this
doesn't survive the first downpour.
>>If cement stops water getting in, there isn't a probelm with it getting
>>out.
>>The wall doesn't get damp in the first place.
>
> Indeed that is true. But can you guarantee that water won't get in?
> Especially on an old house without rigid foundations?
I'm not a great believer in rising damp in brickwork but I guess it's more
relevant in your neck of the woods. I've seen walls where the lower part
was
damper than the rest but that doesn't mean the damp is rising. Usually
it's
falling damp.
>>I can only say not in my experience. I have re-pointed loads of
brickwork
>>with cement mortar but I have combined it with modern polymers
>>They do not
>>affect the appearance but seem to give it added flexibility. Certainly
>>none
>>of it has cracked over 5-10 year periods.
> Thats interesting. You mean Febmix or suchlike? Lime is sometimes used
> as a plasticiser in cement render too. Do you think it is less
> successful, or is Febmix just more convenient for you?
Feb make an awful lot of additives, including SBR, which increases the
flexibility and adhesion of cement mixes. Allows much thinner layers to be
applied.as a render for example.
I know plasterers use lime in cement renders because it makes the mix more
"buttery" (as one described it). A true plasticiser reduces the amount of
water required to get a workable mix, which in turn results in a stronger
end result.
>>But anything on the plaster will be damaged, which rules out wall
>>coverings
>
> Perhaps it is time for wallhangings to come back into fashion!
Wow, that would make makeovers even faster.......
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Mike
<bi...@biffvernon.freeserve.co.uk> wrote in message
news:1116273657.5...@o13g2000cwo.googlegroups.com...
> Yes, Mike, I agree about the joist ends. It just seemed a simple
> example to illustrate that there may be some good uses for modern
> materials. Not a very good example, on reflection.
It's just the one where restoration people get very entrenched on what is
the correct way. They were "repairing" the joists on one of the Grand
Designs recently under the orders of the conservation officer and I was
literally screaming at the TV much to the wife's amusement.
Other thing I hate are those tie-rods through the building pulling it back
together. The historic way to do it would have been to demolish and rebuild
the wall in the same materials but this seems to have become a total no-no
with COs.
> There are better
> examples in Richard Oxley,. Survey and Repair of Traditional
> Buildings: A Conservation and Sustainable Approach. Donhead 2003
Yes - excellent book. Highly recommended to anybody starting work on an old
building.
Anna Kettle
>together. The historic way to do it would have been to demolish and rebuild
>the wall in the same materials but this seems to have become a total no-no
>with COs.
There is historical precedent for tie rods though. I have a 18thC tie
rod in my house. If I didn't, it wouldn't be here now
bi...@biffvernon.freeserve.co.uk
So have I. I suppose, Mike, you thought the Leaning Tower of Pisa
should have been demolished and rebuilt upright instead of having its
foundations supported. :-)
Aidan
Even Goretex stops acting like Goretex after a surprisingly short time.
A wall will absorb some of the driven rain. Also the wall is permeable
and airborne water vapour will penetrate it from both inside and
outside. When it stops raining, the water in the wall will evaporate
through both the inside and outside surfaces.
In the UK we have to heat our houses for about 6 months of the year.
The warm inside air can carry a lot more water vapour than the cold
outside air. The usual mechanism is that the moisture is entering the
wall from the internal surface and evaporating from the outside
surfaces, but it is constantly changing with the internal and external
conditions.
You seal the outside surface at your peril. I'd suggest you might find
it interesting to research interstitial condensation before you commit
yourself..
bi...@biffvernon.freeserve.co.uk
behave like Goretex (at least not when the Goretex is acting like
Goretex and not like my anorak which does not keep me dry when it rains
- right again Aiden)
Mike
> >Other thing I hate are those tie-rods through the building pulling it
back
> >together. The historic way to do it would have been to demolish and
rebuild
> >the wall in the same materials but this seems to have become a total
no-no
> >with COs.
>
> There is historical precedent for tie rods though. I have a 18thC tie
> rod in my house. If I didn't, it wouldn't be here now
18th century ? Could they cast strong enough metal threads in those days or
is this carved oak based ?
Would love to see this.
Mike
Mike
<bi...@biffvernon.freeserve.co.uk> wrote in message
news:1116312305....@f14g2000cwb.googlegroups.com...
I bet that's what the people who paid for it wanted to builders to do before
they went bust :-)
But I do see a lot of these ties appearing when a simple re-build of part of
the structure would do a far better job to my mind.
Anna Kettle
>18th century ? Could they cast strong enough metal threads in those days or
>is this carved oak based ?
Wrought iron not cast, therefore much stronger
Anna Kettle
>Would love to see this.
If you are ever in Suffolk, give me a ring then. I love showing off my
hovel :)
Anna Kettle
<stuart_no...@ntlworld.com> wrote:
>>>If cement stops water getting in, there isn't a probelm with it getting
>>>out. The wall doesn't get damp in the first place.
>> Indeed that is true. But can you guarantee that water won't get in?
>> Especially on an old house without rigid foundations?
>I'm not a great believer in rising damp in brickwork but I guess it's more
>relevant in your neck of the woods. I've seen walls where the lower part
>was damper than the rest but that doesn't mean the damp is rising. Usually
>it's falling damp.
I wasn't actually thinking of rising damp, which I agree can generally
be traced to banked up earth or somesuch. More, I was thinking of the
design principles of the house. Old houses were built with a bit of
flex in them, a bit like bridges are built today so they don't snap in
a strong crosswind. New houses are built with rigid foundations so
they move as a complete unit and so there is less chance of the mortar
cracking and allowing water to get in
I think its horses for courses
Anna Kettle
<stuart_no...@ntlworld.com> wrote:
>IMO the restoration culture is essentially fuelled by money. What people
>perceive as heritage fetches more money in the housing market.
Whats the problem with that? I don't expect you do plastering for
charity
Anna
Aidan
And I agree with you.
I think Goretex is made from stretched PTFE but it's vapour permeable
property seems to be quite volatile. I read somewhere that about 80
days wear is all you can expect, not something that the manufacturers
mention in the sales literature, for some reason. Not something you
want to discover in the field. Micro-porous paint seems similar in
that it's a good idea that is not entirely reliable.
My point was that, given the warm moisture laden inside air and the
cold & (relatively) dry outside air during the heating season, the
prevailing direction of travel of water vapour is usually from inside
to outside, driven by the difference in the partial pressures. Putting
a 'plastic mac' on a building will usually create more problems than it
solves; the water vapour condenses when the temperature falls below the
dew-point and the wall becomes saturated. The manufacturers' seductive
literature is full of impressive before and after pictures, showing
gleaming bright walls. The acid test would be to speak to the owners or
monitor the moisture content of the walls after 5 or 10 years.
Strangely, this is also something that isn't much mentioned in the
sales literature.
Mike
> On Tue, 17 May 2005 21:52:45 +0100, "Mike" <mi...@nospam.com> wrote:
>
> >Would love to see this.
>
> If you are ever in Suffolk, give me a ring then. I love showing off my
> hovel :)
Might be worth a trip. Didn't realise metal wall ties were so old. Do you
have a more precise date on when it was installed ? Also any photos ?
Many thanks
Mike
bi...@biffvernon.freeserve.co.uk
that it's a good idea that is not entirely reliable.
Yes, stay with real linseed oil paint.
Anna Kettle
The crown post tie was cut out at some point and the house started to
fall apart - some of the timber joints have opened up 1.5 inches. I am
guessing that someone panicked a bit and all the metalwork was put in
at the same time to hold the house together. If so then there is a
fairly precise date of ... umm if I remember rightly .... 1730ish cos
elsewhere in the metalwork there is a device which is the precursor to
the nutandbolt and which was in vogue for only about 20 years so I am
told
I've no photos of the tie which is mostly hidden in the ceiling
plasterwork so not very photogenic
Mike
> >>
> >> >Would love to see this.
> >>
> >> If you are ever in Suffolk, give me a ring then. I love showing off my
> >> hovel :)
> >
> >Might be worth a trip. Didn't realise metal wall ties were so old. Do
you
> >have a more precise date on when it was installed ? Also any photos ?
>
> The crown post tie was cut out at some point and the house started to
> fall apart - some of the timber joints have opened up 1.5 inches. I am
> guessing that someone panicked a bit and all the metalwork was put in
> at the same time to hold the house together. If so then there is a
> fairly precise date of ... umm if I remember rightly .... 1730ish cos
> elsewhere in the metalwork there is a device which is the precursor to
> the nutandbolt and which was in vogue for only about 20 years so I am
> told
I'm quite amazed they used metal for this purpose that early on when I would
have thought such metalwork would still have been very expensive.
How long is the tie ?
> I've no photos of the tie which is mostly hidden in the ceiling
> plasterwork so not very photogenic
A real pity. I assume you don't intend to be re-doing this plasterwork
anytime soon :-)
Anna Kettle
>I'm quite amazed they used metal for this purpose that early on when I would
>have thought such metalwork would still have been very expensive.
>How long is the tie ?
Maybe still cheaper than a new house? but I'm not at all knowledgeable
about old metalwork. The tie is about 23 feet long and an inverted U
shape. Cue ascii art:
-------------
/ \ <-Iron tie
[]/ \[] <-Cross section of wallplate
There is a bolt head visible on the inside but I can't see the outside
of the timber to check if its the same prenut'nbolt fixing as
elsewhere in the house cos the old parget (c1800) is intact there. The
parget gives a latest date for the metalwork
>A real pity. I assume you don't intend to be re-doing this plasterwork
>anytime soon :-)
Sorry! Its a quality bit of haired lime plaster on riven oak lath and
only needs a coat of limewash :)
I must share my latest excitement with you - I've just been
rerendering the gable end and found remains of the plaster which was
in place before the c1800 replastering. The old plaster was onto a
layer of daub which covered right over the timbers. On top of the daub
was a thin 4mm smooth coat of East Anglian hairy chalk plaster. I've
not found this on the outside of a building before - it survives
better indoors
Mike
> On Wed, 18 May 2005 22:49:09 +0100, "Mike" <mi...@nospam.com> wrote:
>
> >I'm quite amazed they used metal for this purpose that early on when I
would
> >have thought such metalwork would still have been very expensive.
> >How long is the tie ?
>
> Maybe still cheaper than a new house? but I'm not at all knowledgeable
> about old metalwork. The tie is about 23 feet long and an inverted U
> shape. Cue ascii art:
>
> -------------
> / \ <-Iron tie
> []/ \[] <-Cross section of wallplate
That is very impressive for that era. Must have cost almost as much as the
rest of the house. I would guess that it has been made specially by one of
the cannon manufacturers that existed in your area back then.
> I must share my latest excitement with you - I've just been
> rerendering the gable end and found remains of the plaster which was
> in place before the c1800 replastering. The old plaster was onto a
> layer of daub which covered right over the timbers. On top of the daub
> was a thin 4mm smooth coat of East Anglian hairy chalk plaster. I've
> not found this on the outside of a building before - it survives
> better indoors
Any ideas as to why they would have put it there in the first place ?
Aidan
been made individually from wrought iron by blacksmiths until Whitworth
established uniform interchangeable screw threads. I'm not certain of
the facts. A bit of Googling found the Blacksmiths' Gazette home page
(!) and this item;
"On a more modern reference, in the 1703 edition of Mechanick
Exercises or the Doctrine of Handy-Works, Joseph Moxon refers to the
screw-plate and its taps as a standard piece of equipment in the
blacksmith shop. He describes the screw plate as having several holes
in it, each less than the others. He says that these holes are threads
grooved inwards, into which grooves fit the respective taps that belong
to them. Sounds like the tap was made and then a hole was punched or
drilled and a threaded hole was made in the screw plate with the tap.
The screw plate was used to make the external thread and the tap to
make the internal thread. A screw plate with several taps would be
similar to a set of taps and dies today. I had recently researched this
subject trying to determine exactly when screw threads were invented
and the methods for making them in those early beginnings. If someone
comes up with something better, I would be most pleased."
I think this would have been within the abilities of most smithies by
early 18thC.
Mike
"Aidan" <amc...@hotmail.com> wrote in message
news:1116531574.5...@g43g2000cwa.googlegroups.com...
It wasn't so much the actual use of threads so much as them surviving the
force that would needed to be applied to pull a house back together again
that I found impressive for the time. Anna's tie was so long I doubt the
average smithy could deal with it.
DJC
> the facts. A bit of Googling found the Blacksmiths' Gazette home page
> (!) and this item;
...
> subject trying to determine exactly when screw threads were invented
> and the methods for making them in those early beginnings. If someone
> comes up with something better, I would be most pleased."
There is evidence that the making of screw threads in both wood and
metal was known in in Greece in the second century BC.
For a wonderful survey of Hellenistic Greek technology and science see
Lucio Russo. The Forgotten Revolution. Springer 2004 (isbn 3-540-20396-6)
--
David Clark
$message_body_include ="PLES RING IF AN RNSR IS REQIRD"
Aidan
technique would also have been within the abilities of the local smith
I'd think, but I don't claim to be an expert. At that length, it would
have to be fabricated nearby or on-site.
bi...@biffvernon.freeserve.co.uk
the
force that would needed to be applied to pull a house back together
again
that I found impressive for the time
Could it be that the tie bar's function is to limit further movement
rather than to actually pull the house together again?
Rod
@g44g2000cwa.googlegroups.com:
Many years ago I was similarly curious as to how they handled this. I was
told that they heated up the rod in situ, tightened up the threaded portion
'finger tight' and then, as it cooled down, the contraction drew the
structure together.
Not in the least sure that I believed it then, but it did have a certain
logic. I have a mental picture of the house with no roof and a bloomin'
great bonfire in the middle. Possibly not quite what they did...
--
Rod
Mike
"Rod" <spam....@ntlworld.com> wrote in message
news:Xns965CCD843B51Eh...@130.133.1.4...
Possible I suppose. Hate to be the person who got the sums wrong and the
rod contracted too far :-)
Andy Wade
> There is evidence that the making of screw threads in both wood and
> metal was known in in Greece in the second century BC.
http://en.wikipedia.org/wiki/Screw has this to say on the subject:
"In antiquity, the Greek mathematician Archytas of Tarentum (428 – 350
BC) was credited with the invention of the screw. By the 1st century BC,
wooden screws were commonly used throughout the Mediterranean world in
devices such as oil and wine presses. Metal screws did not appear in
Europe until the 1400s.
"The metal screw did not become a common woodworking fastener until
machine tools for mass producing it were developed at the end of the
18th century. The British engineer Henry Maudslay patented a
screw-cutting lathe in 1797; a similar device was patented by David
Wilkinson in the United States the next year.
"Standardization of screw thread forms accelerated during WWII so that
interchangeable parts could be produced by any of the Allied countries."
There's a fascinating page about Joseph Whitworth too, here:
http://en.wikipedia.org/wiki/Joseph_Whitworth (takes me back to doing
him for O-level metalwork).
--
Andy
Anna Kettle
>@g44g2000cwa.googlegroups.com:
>
>> It wasn't so much the actual use of threads so much as them surviving
>> the
>> force that would needed to be applied to pull a house back together
>> again
>> that I found impressive for the time
I suspect that it is not a screw thread. All I can see from the inside
is ... Cue more ascii art ...
-------| |------ <-- Top of elm wallplate
| | <-- End of iron strap appears through plaster
|*| <-- Head of screw, bolt or whatever
| |
-
---------------- <-- Bottom of elm wallplate
As this is the inside of the U-tie the force would all be on the
threading which would not be good today let alone 200+ years ago, so I
suspect that what I can see is the head of a rod which goes through to
the outside of the wallplate, has a slot cut in it and an iron wedge
driven into that slot. I have no proof of this, but it is a technique
used elsewhere in the house
Anna
>>
>> Could it be that the tie bar's function is to limit further movement
>> rather than to actually pull the house together again?
>>
>
>Many years ago I was similarly curious as to how they handled this. I was
>told that they heated up the rod in situ, tightened up the threaded portion
>'finger tight' and then, as it cooled down, the contraction drew the
>structure together.
>
>Not in the least sure that I believed it then, but it did have a certain
>logic. I have a mental picture of the house with no roof and a bloomin'
>great bonfire in the middle. Possibly not quite what they did...
>
>--
>Rod
Anna Kettle
>That is very impressive for that era. Must have cost almost as much as the
>rest of the house. I would guess that it has been made specially by one of
>the cannon manufacturers that existed in your area back then.
Cannon manufacturers is a new one on me?! Tell me more. It is a line
of industry I don't know anything about. The two top blacksmiths I
know of round here were Garratts of Leiston and Ransomes of Ipswich
both of which I think started c1780 and specialised in agricultural
machinery
>> I must share my latest excitement with you - I've just been
>> rerendering the gable end and found remains of the plaster which was
>> in place before the c1800 replastering. The old plaster was onto a
>> layer of daub which covered right over the timbers. On top of the daub
>> was a thin 4mm smooth coat of East Anglian hairy chalk plaster. I've
>> not found this on the outside of a building before - it survives
>> better indoors
>
>Any ideas as to why they would have put it there in the first place ?
You mean why was the daub plastered and limewashed, instead of just
limewashed? I suspect cos they could. This was one of the richest
parts of the country until 1750 and a daubed and plastered and
limewashed house would need repair less often than a daubed and
limewashed one. Proof being that there is 3sqm intact 250-500 years
later
Mike
> >bi...@biffvernon.freeserve.co.uk wrote in news:1116584638.759634.120340
> >@g44g2000cwa.googlegroups.com:
> >
> >> It wasn't so much the actual use of threads so much as them surviving
> >> the
> >> force that would needed to be applied to pull a house back together
> >> again
> >> that I found impressive for the time
>
> I suspect that it is not a screw thread. All I can see from the inside
> is ... Cue more ascii art ...
>
> -------| |------ <-- Top of elm wallplate
> | | <-- End of iron strap appears through plaster
> |*| <-- Head of screw, bolt or whatever
> | |
> -
> ---------------- <-- Bottom of elm wallplate
>
> As this is the inside of the U-tie the force would all be on the
> threading which would not be good today let alone 200+ years ago, so I
> suspect that what I can see is the head of a rod which goes through to
> the outside of the wallplate, has a slot cut in it and an iron wedge
> driven into that slot. I have no proof of this, but it is a technique
> used elsewhere in the house
Makes sense.
Though a modern thread could take the forces involved.
Mike
> On Thu, 19 May 2005 19:56:08 +0100, "Mike" <mi...@nospam.com> wrote:
>
> >That is very impressive for that era. Must have cost almost as much as
the
> >rest of the house. I would guess that it has been made specially by one
of
> >the cannon manufacturers that existed in your area back then.
>
> Cannon manufacturers is a new one on me?! Tell me more. It is a line
> of industry I don't know anything about.
The east of England from the Wash down to Brighton was home to a large
number of cannon makers from at least the time of Henry VIII, triggered by
his growth in the Navy and use of protective battlements along the shore.
In Elizabethan times output exceeded demand from home use and a lucrative
export market began. At first this was to Holland and so on, friendly
countries, but when our cannon were found in French and Spanish hands enough
was enough and the queen banned exports so some of the cannon makers had to
look for alternative outlets for their metalworking skills. I would guess
one of these was the forerunner to whoever made your tie.
Anna Kettle
>The east of England from the Wash down to Brighton was home to a large
>number of cannon makers from at least the time of Henry VIII, triggered by
>his growth in the Navy and use of protective battlements along the shore.
>In Elizabethan times output exceeded demand from home use and a lucrative
>export market began. At first this was to Holland and so on, friendly
>countries, but when our cannon were found in French and Spanish hands enough
>was enough and the queen banned exports so some of the cannon makers had to
>look for alternative outlets for their metalworking skills. I would guess
>one of these was the forerunner to whoever made your tie.
I wonder why the industry was in East Anglia cos there is no coal or
wood or iron, so I suppose it all came in by water and the
ironworkings were near the coast. I had always assumed cannon were
cast not wrought but maybe they needed both skills