I've got a Victorian semi, and the brick walls go above the roof. On top
of those walls is a coping of pre-cast concrete lengths - each one a
couple of feet or so long - replaced along with the roof some years ago.

At the end of this wall (front of the house) is a typical Victorian cast
stone. Which included a short length of this coping stone - but all in
one, so would tend to retain the others. This stone is three brick courses
high (at the front) and extends about 2.5 ft back into the wall.

And is spalling badly. One worse than the other - and of course it's the
one between the two houses, on the party wall.

When the roof was replaced about 30 years ago, the roofers rendered this
stone - and that has all fallen off, bit by bit. Luckily no-one was
injured by the falling chunks.

The house is scaffolded for painting, so I have reasonable access. But
only on my side of this central stone.

In an ideal world, I'd remove it. Make up some shuttering and cast up a
new one. But I don't fancy doing any damage to next door's roof - and I
can't get access to that side from the scaffolding anyway.

I've got a load of lime mortar made specifically for fixing this sort of
stone. It would be possible to fix shuttering to the existing stone to
remake the coping part. But just how well would the lime mortar hold?

I'll take some pics and put a link to them if it would help.

--
*Whatever kind of look you were going for, you missed.

Dave Plowman London SW
To e-mail, change noise into sound.

On 7/29/2017 2:31 PM, Dave Plowman (News) wrote:
I've got a Victorian semi, and the brick walls go above the roof. On top
of those walls is a coping of pre-cast concrete lengths - each one a
couple of feet or so long - replaced along with the roof some years ago.

At the end of this wall (front of the house) is a typical Victorian cast
stone. Which included a short length of this coping stone - but all in
one, so would tend to retain the others. This stone is three brick courses
high (at the front) and extends about 2.5 ft back into the wall.

And is spalling badly. One worse than the other - and of course it's the
one between the two houses, on the party wall.

When the roof was replaced about 30 years ago, the roofers rendered this
stone - and that has all fallen off, bit by bit. Luckily no-one was
injured by the falling chunks.

The house is scaffolded for painting, so I have reasonable access. But
only on my side of this central stone.

In an ideal world, I'd remove it. Make up some shuttering and cast up a
new one. But I don't fancy doing any damage to next door's roof - and I
can't get access to that side from the scaffolding anyway.

I've got a load of lime mortar made specifically for fixing this sort of
stone. It would be possible to fix shuttering to the existing stone to
remake the coping part. But just how well would the lime mortar hold?

I'll take some pics and put a link to them if it would help.

Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws.

Are you talking about pure lime mortar, or one containing some cement as
well? My suspicion is that while simple lime/sand is fine for repointing
and filling cracks, you might want something a little bit stronger here.

On Saturday, 29 July 2017 14:31:16 UTC+1, Dave Plowman (News) wrote:
I've got a Victorian semi, and the brick walls go above the roof. On top
of those walls is a coping of pre-cast concrete lengths - each one a
couple of feet or so long - replaced along with the roof some years ago.

At the end of this wall (front of the house) is a typical Victorian cast
stone. Which included a short length of this coping stone - but all in
one, so would tend to retain the others. This stone is three brick courses
high (at the front) and extends about 2.5 ft back into the wall.

And is spalling badly. One worse than the other - and of course it's the
one between the two houses, on the party wall.

When the roof was replaced about 30 years ago, the roofers rendered this
stone - and that has all fallen off, bit by bit. Luckily no-one was
injured by the falling chunks.

The house is scaffolded for painting, so I have reasonable access. But
only on my side of this central stone.

In an ideal world, I'd remove it. Make up some shuttering and cast up a
new one. But I don't fancy doing any damage to next door's roof - and I
can't get access to that side from the scaffolding anyway.

I've got a load of lime mortar made specifically for fixing this sort of
stone. It would be possible to fix shuttering to the existing stone to
remake the coping part. But just how well would the lime mortar hold?

I'll take some pics and put a link to them if it would help.

Is the period property forum still going?


NT

In article ,
newshound wrote:
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws.

That was in my mind too. One thought was to cut the coping part off with
an angle grinder and cut down one of those readily available cast ones to
the correct length. And fit it to the original stone in some way as well
as with the mortar, like screws.

Sadly, there's nothing in the instructions about what metal is best with
lime. SS would be easy if it is good.

Are you talking about pure lime mortar, or one containing some cement as
well? My suspicion is that while simple lime/sand is fine for repointing
and filling cracks, you might want something a little bit stronger here.

It's the stuff Conserv supply ready mixed to repair this sort of stone -
by their website. In what little I've read they caution about adding
cement - ever.

--
*Taxation WITH representation ain't much fun, either.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
I've got a load of lime mortar made specifically for fixing this sort
of stone. It would be possible to fix shuttering to the existing
stone to remake the coping part. But just how well would the lime
mortar hold?

I'll take some pics and put a link to them if it would help.

Is the period property forum still going?

I've Googled for any help, but all I can find is ads for companies
offering this sort of service. A link to a website which covers it as DIY
would be very useful.

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, 29 July 2017 16:07:14 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

I've got a load of lime mortar made specifically for fixing this sort
of stone. It would be possible to fix shuttering to the existing
stone to remake the coping part. But just how well would the lime
mortar hold?

I'll take some pics and put a link to them if it would help.

Is the period property forum still going?

I've Googled for any help, but all I can find is ads for companies
offering this sort of service. A link to a website which covers it as DIY
would be very useful.

http://www.periodproperty.co.uk/forum/index.php
I offer no guarantees, but I'd start by trying there.


NT

Dave Plowman (News) wrote:

In article ,
newshound wrote:
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws.

That was in my mind too. One thought was to cut the coping part off with
an angle grinder and cut down one of those readily available cast ones to
the correct length. And fit it to the original stone in some way as well
as with the mortar, like screws.

Sadly, there's nothing in the instructions about what metal is best with
lime. SS would be easy if it is good.

Are you talking about pure lime mortar, or one containing some cement as
well? My suspicion is that while simple lime/sand is fine for repointing
and filling cracks, you might want something a little bit stronger here.

It's the stuff Conserv supply ready mixed to repair this sort of stone -
by their website. In what little I've read they caution about adding
cement - ever.

More than a small proportion (exact figure unknown to me) of cement
turns it into relatively-weak well plasticised cement mortar.
Especially it gives it the undesirable property of being impervious.
But it is somewhat mechanically stronger.


--

Roger Hayter

On Saturday, 29 July 2017 19:00:07 UTC+1, Roger Hayter wrote:
Dave Plowman (News) wrote:
In article ,
newshound wrote:

Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws.

That was in my mind too. One thought was to cut the coping part off with
an angle grinder and cut down one of those readily available cast ones to
the correct length. And fit it to the original stone in some way as well
as with the mortar, like screws.

Sadly, there's nothing in the instructions about what metal is best with
lime. SS would be easy if it is good.

Are you talking about pure lime mortar, or one containing some cement as
well? My suspicion is that while simple lime/sand is fine for repointing
and filling cracks, you might want something a little bit stronger here.

It's the stuff Conserv supply ready mixed to repair this sort of stone -
by their website. In what little I've read they caution about adding
cement - ever.

More than a small proportion (exact figure unknown to me) of cement
turns it into relatively-weak well plasticised cement mortar.
Especially it gives it the undesirable property of being impervious.
But it is somewhat mechanically stronger.

that's true when the cement strength equals/exceeds lime strength. At 5% cement it's not, the cement just enables a quick (weak) set. The reason most cement/lime mixes are deprecated is that ratios other than 1:1 have been found to be at risk of premature failure in practice. The other reason is that as you say non-low cement content changes the properties of the mortar for the worse.

If adding 5% makes the difference between getting the job done or not I'd do it, and accept the degree of risk. If you can get it done a better way, great. Adding 5% is an often accepted tradeoff.


NT

On Saturday, 29 July 2017 19:00:07 UTC+1, Roger Hayter wrote:
Dave Plowman (News) wrote:
In article ,
newshound wrote:

Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws.

That was in my mind too. One thought was to cut the coping part off with
an angle grinder and cut down one of those readily available cast ones to
the correct length. And fit it to the original stone in some way as well
as with the mortar, like screws.

Sadly, there's nothing in the instructions about what metal is best with
lime. SS would be easy if it is good.

Are you talking about pure lime mortar, or one containing some cement as
well? My suspicion is that while simple lime/sand is fine for repointing
and filling cracks, you might want something a little bit stronger here.

It's the stuff Conserv supply ready mixed to repair this sort of stone -
by their website. In what little I've read they caution about adding
cement - ever.

More than a small proportion (exact figure unknown to me) of cement
turns it into relatively-weak well plasticised cement mortar.
Especially it gives it the undesirable property of being impervious.
But it is somewhat mechanically stronger.

that's true when the cement strength equals/exceeds lime strength. At 5% cement it's not, the cement just enables a quick (weak) set. The reason most cement/lime mixes are deprecated is that ratios other than 1:1 have been found to be at risk of premature failure in practice. The other reason is that as you say non-low cement content changes the properties of the mortar for the worse.

If adding 5% makes the difference between getting the job done or not I'd do it, and accept the degree of risk. If you can get it done a better way, great. Adding 5% is an often accepted tradeoff.


NT

wrote:

If you can get it done a better way, great. Adding 5% is an often accepted tradeoff.

Worth adding some fibres to the lime mortar?

http://cornishlime.co.uk/products/associated-building-products/hair-fibres-mesh

On 29-Jul-17 2:41 PM, newshound wrote:
....
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.


--
--

Colin Bignell

On 7/29/2017 7:57 PM, Nightjar wrote:
On 29-Jul-17 2:41 PM, newshound wrote:
...
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in
some screws protruding a certain amount from the surface. I think I
would use stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.


I don't think I agree. In an alkaline environment there is nothing
present that is going to degrade the protective oxide, so why do you
need any additional oxygen. In any case, in a "breathable" mortar
there's always going to be some water (and hence oxygen) present by
diffusion from the outside.

Excuse me if I digress, but I did have one interesting instance in the
past where austenitic stainless steel was corroding at an alarming rate
in an alkaline environment. My current house has thick rubble-filled
random limestone walls built straight on the underlying limestone. And I
have a 100 metre hill rising within a kilometer behind the house. The
previous owner, towards the end of his life, dealt with the chronic
rising damp problem by putting (untreated) studding on the end wall,
stapling thick polyethylene sheet over this, then plasterboarding and
plastering. (The exterior surface was cement rendered with the
traditional bell-cast above a few inches of exposed stonework).

As a result, when we moved in the dry rot had reached many of the first
floor joists, as well as taking out the staircase in one corner and the
window frame in the other.

Being in those days totally dependent on a commercial mortgage, I had no
choice but to follow the advice of an approved "damp specialist". They
ripped out the studding and plasterboard, replaced the staircase, window
frames and doors, put in an electro osmotic damp proof course, and
re-rendered inside with waterproof sand/cement rendering, topped with
gypsum plaster. (They did use Sirapite on another wall).

This of course sealed in all the rising damp that was forced up by the
fact that the normal water table was at least half way up the wall. In
due course, the gypsum plaster blew out. Also, the new radiator fell off
the wall when the screws rusted through.

At this point I thought I would be clever. I got four lengths of 8 mm
austenitic (18-8) stainless steel studding about 15 inches long, set
these into the wall, and hung the radiator brackets on them. (At this
time I had small children, no money, and was just living with the rising
damp).

After a while I decided I needed to sort the damp properly, so I moved
the radiator to a better location, and stripped off all the interior
rendering to allow the wall to dry out properly. (The exterior rendering
was on the site boundary and faced a garage forecourt, I didn't really
want to tackle that wall). I was interested to find very substantial
corrosion on the "stainless" studding that had been holding up the
radiators. But by that time, I had also discovered that 90% of the metal
in standard galvanised electrical back boxes had also vanished on
another really wet wall. On checking the polarity of my "electro
osmotic" damp proof course (which was made from titanium wire) I decided
that the iron loss in both the mild and the stainless steel had actually
been caused by the electrochemistry because the back boxes, and also the
radiator and hence the brackets and supporting studs were well earthed.
Reverse electroplating, if you like. Provided the wall was wet (and
therefore conductive) enough, current from the protection system was
just converting any earthed metal into ions.

With all the rendering stripped, I found after a few months that I got a
little bit of salt formation on the bottom couple of feet, but the rest
of the wall remained dry. So I made the top of the wall a "feature", had
it properly pointed by an expert, and fitted well ventilated
wainscotting over the bottom three feet or so. And that has completely
cured my rising damp.

I have a few photos documenting this work. I do wonder, from time to
time, whether I ought to submit something to the DIY Wiki.

Going back to Colin's original suggestion of non-ferrous metal for the
OP's problem, I will confess to wondering whether to suggest brass
screws rather than stainless. The trouble is, readily available brass
screws will just be simple copper/zinc. Perhaps you need the 1% of tin
that is in "Admiralty brass" to improve the corrosion resistance. Or
perhaps you need something moving further into the gun-metals and
bronzes: not necessarily so easy to find, short of going to chandlers
with many pound notes.

I still think that the readily available A2 stainless should work.
Disclaimer: I'm not a proper chemist and happy to be corrected.

On 7/29/2017 6:31 PM, wrote:
On Saturday, 29 July 2017 16:07:14 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

I've got a load of lime mortar made specifically for fixing this sort
of stone. It would be possible to fix shuttering to the existing
stone to remake the coping part. But just how well would the lime
mortar hold?

I'll take some pics and put a link to them if it would help.

Is the period property forum still going?

I've Googled for any help, but all I can find is ads for companies
offering this sort of service. A link to a website which covers it as DIY
would be very useful.

http://www.periodproperty.co.uk/forum/index.php
I offer no guarantees, but I'd start by trying there.


NT


+1

Certainly worth looking. I've found some interesting stuff there in the
past. But this NG is always the first place I look.

In article ,
Andy Burns wrote:
wrote:

If you can get it done a better way, great. Adding 5% is an often
accepted tradeoff.

Worth adding some fibres to the lime mortar?

http://cornishlime.co.uk/products/associated-building-products/hair-fibres-mesh

Yes - was thinking about that. When the rain stopped I had another look.
What I think I'd like to do is re-make the coping stone top to this one.
It would be easy to fit some shuttering and cast on top of the remains.
After removing all the loose bits, the rest appears sound.

The traditional stuff was horse hair. I wondered about using glass fibre -
since that is easily obtianed. And is used in those lightweight concrete
tiles you get for say a roof terrace.

--
*Women who seek to be equal to men lack ambition.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Nightjar wrote:
On 29-Jul-17 2:41 PM, newshound wrote:
...
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in
some screws protruding a certain amount from the surface. I think I
would use stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.

Brass screws are easy enough to get. Surely plastic wall plugs would be OK
with lime?

--
*All men are idiots, and I married their King.

Dave Plowman London SW
To e-mail, change noise into sound.

On 30-Jul-17 12:18 AM, Dave Plowman (News) wrote:
In article ,
Nightjar wrote:
On 29-Jul-17 2:41 PM, newshound wrote:
...
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in
some screws protruding a certain amount from the surface. I think I
would use stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.

Brass screws are easy enough to get. Surely plastic wall plugs would be OK
with lime?


I would use bronze, rather than brass. Bronze screws are readily
available online. Plastic wall plugs should be OK if the stone is sound
enough to take the expansion force.

--
--

Colin Bignell

Hmm, so I take it the neighbour concerned is doing their impression of an
Ostrich then? There would seem to be no better time to get this sorted for
years to come at a reasonable cost than now, so if they don't want to do it,
all you can do is your bit.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
I've got a Victorian semi, and the brick walls go above the roof. On top
of those walls is a coping of pre-cast concrete lengths - each one a
couple of feet or so long - replaced along with the roof some years ago.

At the end of this wall (front of the house) is a typical Victorian cast
stone. Which included a short length of this coping stone - but all in
one, so would tend to retain the others. This stone is three brick courses
high (at the front) and extends about 2.5 ft back into the wall.

And is spalling badly. One worse than the other - and of course it's the
one between the two houses, on the party wall.

When the roof was replaced about 30 years ago, the roofers rendered this
stone - and that has all fallen off, bit by bit. Luckily no-one was
injured by the falling chunks.

The house is scaffolded for painting, so I have reasonable access. But
only on my side of this central stone.

In an ideal world, I'd remove it. Make up some shuttering and cast up a
new one. But I don't fancy doing any damage to next door's roof - and I
can't get access to that side from the scaffolding anyway.

I've got a load of lime mortar made specifically for fixing this sort of
stone. It would be possible to fix shuttering to the existing stone to
remake the coping part. But just how well would the lime mortar hold?

I'll take some pics and put a link to them if it would help.

--
*Whatever kind of look you were going for, you missed.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Brian Gaff wrote:
Hmm, so I take it the neighbour concerned is doing their impression of
an Ostrich then? There would seem to be no better time to get this
sorted for years to come at a reasonable cost than now, so if they
don't want to do it, all you can do is your bit.

No - quite the reverse. They've offered to pay their share of the costs.

The main snag is the scaffolding stops on my side - so not safe to get
round to 'their' side of this wall. I can get to the top of this stone ok
and of course my side and the front. But not to their side. Where their
flashing goes into it.

--
*When did my wild oats turn to prunes and all bran?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Nightjar wrote:
Brass screws are easy enough to get. Surely plastic wall plugs would be OK
with lime?


I would use bronze, rather than brass. Bronze screws are readily
available online. Plastic wall plugs should be OK if the stone is sound
enough to take the expansion force.

Ah - right. The instruction I have do mention bronze tools, etc. I'll
order up some bronze screws. They will go towards the centre of the block
which seems still sound.

--
*People want trepanners like they want a hole in the head*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Andy Burns wrote:
wrote:

If you can get it done a better way, great. Adding 5% is an often
accepted tradeoff.

Worth adding some fibres to the lime mortar?

http://cornishlime.co.uk/products/associated-building-products/hair-fibres-mesh

Looks like a fibreglass mesh might be the easiest way?

--
*He who dies with the most toys is, nonetheless, dead.

Dave Plowman London SW
To e-mail, change noise into sound.

On 29/07/2017 21:05, newshound wrote:

I have a few photos documenting this work. I do wonder, from time to
time, whether I ought to submit something to the DIY Wiki.

Sounds like it would make a nice article - also we have not got much
along those lines in there at the moment, so it would be handy...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 7/30/2017 1:03 PM, John Rumm wrote:
On 29/07/2017 21:05, newshound wrote:

I have a few photos documenting this work. I do wonder, from time to
time, whether I ought to submit something to the DIY Wiki.

Sounds like it would make a nice article - also we have not got much
along those lines in there at the moment, so it would be handy...

Thanks. What do I need to do? Get access privileges from someone? I've
never updated a Wiki but I (sort of) know my way around markup languages.

On 7/30/2017 9:23 AM, Nightjar wrote:
On 30-Jul-17 12:18 AM, Dave Plowman (News) wrote:
In article ,
Nightjar wrote:
On 29-Jul-17 2:41 PM, newshound wrote:
...
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in
some screws protruding a certain amount from the surface. I think I
would use stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.

Brass screws are easy enough to get. Surely plastic wall plugs would
be OK
with lime?


I would use bronze, rather than brass. Bronze screws are readily
available online. Plastic wall plugs should be OK if the stone is sound
enough to take the expansion force.

I'd be OK with bronze too. I'd probably look at "quality" plugs like
Fischer, they tend to have stronger plastic but more "space" to ensure
that the volume does not go solid when the screw is inserted. You don't
need a very strong fixing (compared to shelf brackets, say), make sure
the screws are not oversized for the plug.

On 30/07/2017 22:37, newshound wrote:
On 7/30/2017 1:03 PM, John Rumm wrote:
On 29/07/2017 21:05, newshound wrote:

I have a few photos documenting this work. I do wonder, from time to
time, whether I ought to submit something to the DIY Wiki.

Sounds like it would make a nice article - also we have not got much
along those lines in there at the moment, so it would be handy...

Thanks. What do I need to do? Get access privileges from someone? I've
never updated a Wiki but I (sort of) know my way around markup languages.

Drop me an email with your preferred account name, and I will create an
account for you.

Wiki markup is pretty straight forward for the basic things. But even if
you just slap in text and upload the photos, there will be someone along
who can help you tart it up.

Getting started instructions he

http://wiki.diyfaq.org.uk/index.php/...iting_Articles

(we use the same software as wikipedia; "Mediawiki" - so there are tons
of help pages out there)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 30/07/2017 11:18, Dave Plowman (News) wrote:
In article ,
Brian Gaff wrote:
Hmm, so I take it the neighbour concerned is doing their impression of
an Ostrich then? There would seem to be no better time to get this
sorted for years to come at a reasonable cost than now, so if they
don't want to do it, all you can do is your bit.

No - quite the reverse. They've offered to pay their share of the costs.

The main snag is the scaffolding stops on my side - so not safe to get
round to 'their' side of this wall. I can get to the top of this stone ok
and of course my side and the front. But not to their side. Where their
flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the stone?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
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On 29-Jul-17 9:05 PM, newshound wrote:
....
I still think that the readily available A2 stainless should work.
Disclaimer: I'm not a proper chemist and happy to be corrected.

Which is more likely to cause problems in the long term; assuming it
could rust and being wrong or assuming it won't and being wrong?

--
--

Colin Bignell

On 30-Jul-17 11:20 AM, Dave Plowman (News) wrote:
In article ,
Nightjar wrote:
Brass screws are easy enough to get. Surely plastic wall plugs would be OK
with lime?


I would use bronze, rather than brass. Bronze screws are readily
available online. Plastic wall plugs should be OK if the stone is sound
enough to take the expansion force.

Ah - right. The instruction I have do mention bronze tools, etc. I'll
order up some bronze screws. They will go towards the centre of the block
which seems still sound.


I like bronze for outside fastenings. I made a pair of gates for a
driveway about 40 years ago, using silicon bronze ring barb nails. Apart
from the weather capping strip needing to be replaced after about 20
years, the gates are still doing good service for the current owners. A
custom made garden bench, not made by me and using brass fastenings,
fell apart after only 20 years.

--
--

Colin Bignell

In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to get
round to 'their' side of this wall. I can get to the top of this stone
ok and of course my side and the front. But not to their side. Where
their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the stone?

Absolutely not at my age. ;-)

--
*For every action, there is an equal and opposite criticism *

Dave Plowman London SW
To e-mail, change noise into sound.

On 7/31/2017 10:06 AM, Nightjar wrote:
On 29-Jul-17 9:05 PM, newshound wrote:
...
I still think that the readily available A2 stainless should work.
Disclaimer: I'm not a proper chemist and happy to be corrected.

Which is more likely to cause problems in the long term; assuming it
could rust and being wrong or assuming it won't and being wrong?

My eminent old colleague Jack Harris advised on repairs to St Paul's,
although I can't immediately locate details of the replacement metal parts.

https://www.theguardian.com/world/20...rris-scientist

However, the very long studs which now hold together the corners of the
tower of York Minster are certainly made from austenitic stainless steel.

On 7/31/2017 12:19 PM, newshound wrote:
On 7/31/2017 10:06 AM, Nightjar wrote:
On 29-Jul-17 9:05 PM, newshound wrote:
...
I still think that the readily available A2 stainless should work.
Disclaimer: I'm not a proper chemist and happy to be corrected.

Which is more likely to cause problems in the long term; assuming it
could rust and being wrong or assuming it won't and being wrong?

My eminent old colleague Jack Harris advised on repairs to St Paul's,
although I can't immediately locate details of the replacement metal parts.

https://www.theguardian.com/world/20...rris-scientist


However, the very long studs which now hold together the corners of the
tower of York Minster are certainly made from austenitic stainless steel.

These people sell stainless steel fittings so are hardly unbiassed, but
they seem to think it is OK in mortar and stonework

http://www.ssina.com/download_a_file/wallties.pdf

On 31/07/2017 11:03, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to get
round to 'their' side of this wall. I can get to the top of this stone
ok and of course my side and the front. But not to their side. Where
their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the stone?

Absolutely not at my age. ;-)

Get a bit added onto to the scaffolding then... cheaper now than having
a whole new lot up later.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
On 31/07/2017 11:03, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to
get round to 'their' side of this wall. I can get to the top of this
stone ok and of course my side and the front. But not to their side.
Where their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the stone?

Absolutely not at my age. ;-)

Get a bit added onto to the scaffolding then... cheaper now than having
a whole new lot up later.

That would be up to my neighbours. I can't have scaffolding extended onto
their land.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, 29 July 2017 14:31:16 UTC+1, Dave Plowman (News) wrote:
I've got a Victorian semi, and the brick walls go above the roof. On top
of those walls is a coping of pre-cast concrete lengths - each one a
couple of feet or so long - replaced along with the roof some years ago.

At the end of this wall (front of the house) is a typical Victorian cast
stone. Which included a short length of this coping stone - but all in
one, so would tend to retain the others. This stone is three brick courses
high (at the front) and extends about 2.5 ft back into the wall.

And is spalling badly. One worse than the other - and of course it's the
one between the two houses, on the party wall.

When the roof was replaced about 30 years ago, the roofers rendered this
stone - and that has all fallen off, bit by bit. Luckily no-one was
injured by the falling chunks.

The house is scaffolded for painting, so I have reasonable access. But
only on my side of this central stone.

In an ideal world, I'd remove it. Make up some shuttering and cast up a
new one. But I don't fancy doing any damage to next door's roof - and I
can't get access to that side from the scaffolding anyway.

I've got a load of lime mortar made specifically for fixing this sort of
stone. It would be possible to fix shuttering to the existing stone to
remake the coping part. But just how well would the lime mortar hold?

I'll take some pics and put a link to them if it would help.

--
*Whatever kind of look you were going for, you missed.

Dave Plowman London SW
To e-mail, change noise into sound.

The stone at the end is called a kneeler.
Always good to know the terminology.
Example:-
http://www.churchfieldstone.co.uk/pr...-Kneelers.html

In article ,
Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 31/07/2017 11:03, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to
get round to 'their' side of this wall. I can get to the top of
this stone ok and of course my side and the front. But not to
their side. Where their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the
stone?

Absolutely not at my age. ;-)

Get a bit added onto to the scaffolding then... cheaper now than
having a whole new lot up later.

That would be up to my neighbours. I can't have scaffolding extended
onto their land.

I've had another look. Used a mirror to look at their side better. And if
anything it's in a worse state than my side. A couple of large chunks just
ready to fall off. Not quite sure how to proceed.

--
*Change is inevitable, except from a vending machine*

Dave Plowman London SW
To e-mail, change noise into sound.

On 29/07/2017 21:05, newshound wrote:
In any case, in a "breathable" mortar there's always going to be some
water (and hence oxygen) present by diffusion from the outside.

Water doesn't count. There have been cases where the stainless steel
keelbolts on boats have rusted through - and when the keel falls off
that kind of boat they'll be upside down in seconds.

Andy

On 7/31/2017 8:45 PM, Vir Campestris wrote:
On 29/07/2017 21:05, newshound wrote:
In any case, in a "breathable" mortar there's always going to be some
water (and hence oxygen) present by diffusion from the outside.

Water doesn't count. There have been cases where the stainless steel
keelbolts on boats have rusted through - and when the keel falls off
that kind of boat they'll be upside down in seconds.

Andy

Well, you say "rusted through". My guess is that keel bolts are highly
stressed in extreme conditions. With the chloride in seawater,
unsuitable stainless steels experiences stress corrosion cracking. They
will therefore fracture, rather than "rust through". Whereas in the sort
of case we are describing for the coping stone repair, the stress levels
will be very small compared to the tensile strength of the steel, and
SCC is not a problem.

Disclaimer: I'm not a metallurgist either, I'm a physicist. But I have
spent a career convincing engineers that I know more chemistry than
them, chemists that I know more metallurgy, metallurgists that I know
more physics, and physicists that I know more chemistry, engineering,
and metallurgy! Oh, and I can bluff anyone except a mathematician about
statistics.

On 31/07/2017 18:16, Dave Plowman (News) wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 31/07/2017 11:03, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to
get round to 'their' side of this wall. I can get to the top of
this stone ok and of course my side and the front. But not to
their side. Where their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the
stone?

Absolutely not at my age. ;-)

Get a bit added onto to the scaffolding then... cheaper now than
having a whole new lot up later.

That would be up to my neighbours. I can't have scaffolding extended
onto their land.

I've had another look. Used a mirror to look at their side better. And if
anything it's in a worse state than my side. A couple of large chunks just
ready to fall off. Not quite sure how to proceed.

Can you get a photo of it (selfie stick?) and show them? They might be
keen to go halves on the scaffolding cost, sine the alternative to them
will be at least double later...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
On 31/07/2017 18:16, Dave Plowman (News) wrote:
In article ,
Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 31/07/2017 11:03, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The main snag is the scaffolding stops on my side - so not safe to
get round to 'their' side of this wall. I can get to the top of
this stone ok and of course my side and the front. But not to
their side. Where their flashing goes into it.

Roof ladder hooked onto their side of the roof adjacent to the
stone?

Absolutely not at my age. ;-)

Get a bit added onto to the scaffolding then... cheaper now than
having a whole new lot up later.

That would be up to my neighbours. I can't have scaffolding extended
onto their land.

I've had another look. Used a mirror to look at their side better. And
if anything it's in a worse state than my side. A couple of large
chunks just ready to fall off. Not quite sure how to proceed.

Can you get a photo of it (selfie stick?) and show them? They might be
keen to go halves on the scaffolding cost, sine the alternative to them
will be at least double later...

Yes. The problem is neither of them do anything even vaguely DIY, so I'm
not sure will understand. And I don't want to be in the position of being
responsible if anything goes wrong. Perhaps I'm just over thinking things.

Ideally, if I had good access, I'd remove the entire stone and cast up a
new one out of concrete. But as it is, likely just repair my side and the
top.

--
*It was recently discovered that research causes cancer in rats*

Dave Plowman London SW
To e-mail, change noise into sound.

On 31/07/2017 21:15, newshound wrote:
On 7/31/2017 8:45 PM, Vir Campestris wrote:
On 29/07/2017 21:05, newshound wrote:
In any case, in a "breathable" mortar there's always going to be some
water (and hence oxygen) present by diffusion from the outside.

Water doesn't count. There have been cases where the stainless steel
keelbolts on boats have rusted through - and when the keel falls off
that kind of boat they'll be upside down in seconds.

Andy

Well, you say "rusted through". My guess is that keel bolts are highly
stressed in extreme conditions. With the chloride in seawater,
unsuitable stainless steels experiences stress corrosion cracking. They
will therefore fracture, rather than "rust through". Whereas in the sort
of case we are describing for the coping stone repair, the stress levels
will be very small compared to the tensile strength of the steel, and
SCC is not a problem.

Disclaimer: I'm not a metallurgist either, I'm a physicist. But I have
spent a career convincing engineers that I know more chemistry than
them, chemists that I know more metallurgy, metallurgists that I know
more physics, and physicists that I know more chemistry, engineering,
and metallurgy! Oh, and I can bluff anyone except a mathematician about
statistics.

I have no first hand experience. Lots of links, such as this

http://www.cruisingworld.com/how/keep-eye-keel-bolts

suggest that only some sorts of stainless will survive bilgewater, which
is often low in oxygen.

Andy

In article ,
Nightjar wrote:
On 29-Jul-17 2:41 PM, newshound wrote:
...
Sounds like a plausible idea. The other thing you might think about is
ways to improve the keying. For example you could drill some holes in
the face to be repaired, insert plastic wallplugs, and then put in some
screws protruding a certain amount from the surface. I think I would use
stainless steel screws....

I suspect that stainless steel would not have enough oxygen reaching it
to keep the protective surface coating intact. That would mean it will
rust just as quickly as mild steel. I would use a non-ferrous metal
bonded to the existing stonework with epoxy resin.

Been reading the instructions that came with the Conserv repair mortar,
and they mention SS reinforcement.

--
*Reality is the illusion that occurs due to the lack of alcohol *

Dave Plowman London SW
To e-mail, change noise into sound.