Minor repairs with lime mortar
dent
I live in a 1950's house. It is in a small village near Bath, and so
was built in cast-stone blocks which resemble surrounding houses
(which are Bath stone). The mortar used is very light - almost white -
and powders easily if rubbed, which leads me to think that it may be
lime mortar. Is this likely? I thought that lime mortar was only
really encountered on pre-1930's houses, and not on more recent
buildings? At some point, another owner has added a porch, and the
mortar on that is still very light, but with a distinct grey tinge,
and is very hard to the touch (it doesn't powder when rubbed), so this
would appear to be cement based.
My main question is this. There are various places around the house
where I need to repair the pointing, and fix some ugly holes that the
previous owner filled with grey mortar. I am also replacing my doors
and windows, and need some mortar for bedding down the doors, and
making good in a few places. Should I try to obtain suitable lime
mortar for this work, or could I use cement mortar? Obviously if I
used cement mortar I would have to use suitably coloured sand, and
white cement - would this be a close enough match?
I haven't been able to find any local suppliers of lime mortar
(although living near Bath this seems odd). Getting small quantities
of lime mortar mail order I end up paying twice as much for postage as
I do for the materials!
thanks,
dan.
The Natural Philosopher
> Hi all,
>
> I live in a 1950's house. It is in a small village near Bath, and so
> was built in cast-stone blocks which resemble surrounding houses
> (which are Bath stone). The mortar used is very light - almost white -
> and powders easily if rubbed, which leads me to think that it may be
> lime mortar. Is this likely?
More likely its just shoddy cheap mortar that never had much cement in
it to start with
I thought that lime mortar was only
> really encountered on pre-1930's houses, and not on more recent
> buildings? At some point, another owner has added a porch, and the
> mortar on that is still very light, but with a distinct grey tinge,
> and is very hard to the touch (it doesn't powder when rubbed), so this
> would appear to be cement based.
>
> My main question is this. There are various places around the house
> where I need to repair the pointing, and fix some ugly holes that the
> previous owner filled with grey mortar. I am also replacing my doors
> and windows, and need some mortar for bedding down the doors, and
> making good in a few places. Should I try to obtain suitable lime
> mortar for this work, or could I use cement mortar? Obviously if I
> used cement mortar I would have to use suitably coloured sand, and
> white cement - would this be a close enough match?
I have used a LOT of white cement and sand mixtures..it comes out very
nearly white. I have also added lime to it. It all works pretty well. I
even ran out of cement one time and made a mix that was nearly all lime
and sand..it worked after a fashion..its still a bit soft even today,
but it holds up well enough.
I think my favorite was 1 cement 1 lime and 6-10 sand. Measured in
approximate shovelfuls.
Use more cement if building below the damp course..it makes the cement
less porous and water ingress is reduced.
You can use silver sand,but I found the ordinary yellow stuff was the
right color for me. I also used a lot of sharp sand to get a gritty
mortar to gibe a period feel.
Your applications are not so critical that I would be overly concerned
about ultimate strength etc. Get some materials and mix up some batches
and try and get a color match.
>
> I haven't been able to find any local suppliers of lime mortar
> (although living near Bath this seems odd). Getting small quantities
> of lime mortar mail order I end up paying twice as much for postage as
> I do for the materials!
>
No! simply buy white cement and hydrated lime from the BM..and sharp
sand. Get making mud pies with it till it looks right. Then just use it.
> thanks,
>
> dan.
>
Stuart Noble
Lime putty has to mature like fine wine. Best prepared in the Cotswolds
by someone with a beard and a check shirt
>
>
>> thanks,
>>
>> dan.
>>
The Natural Philosopher
I don't like beards or check shirts. I'll stick to bags of industrial
grade cement and lime thanks.
Most real ale and mead is also atrocious rubbish
Lime putty belongs in a museum. Or someone repairing one.
>
>>
>>
>>> thanks,
>>>
>>> dan.
>>>
Anna Kettle
wrote:
>Stuart Noble wrote:
>> The Natural Philosopher wrote:
>>> dent wrote:
>>>> Hi all,
>>>>
>>>> I live in a 1950's house. It is in a small village near Bath, and so
>>>> was built in cast-stone blocks which resemble surrounding houses
>>>> (which are Bath stone). The mortar used is very light - almost white -
>>>> and powders easily if rubbed, which leads me to think that it may be
>>>> lime mortar. Is this likely?
Yes
>>> I thought that lime mortar was only
>>>> really encountered on pre-1930's houses, and not on more recent
>>>> buildings?
Cement certainly became fashionable after the war when people wanted
quick builds, but lime skills were still around in the 50s
>>>>Should I try to obtain suitable lime
>>>> mortar for this work
Yes. But then I would say that wouldnt I! The critical thing is that
the mortar must be weaker than the blocks. Had the blocks been real
Bath stone then lime mortar would be important cos Bath stone is quite
soft
>>>> I haven't been able to find any local suppliers of lime mortar
>>>> (although living near Bath this seems odd). Getting small quantities
>>>> of lime mortar mail order I end up paying twice as much for postage as
>>>> I do for the materials!
Chard Builders merchant in Bristol is a manufacturer and supplier. Its
good quality stuff but they do tend to sell it too young so I suggest
you buy it now and do the work when the weather improves. Meanwhile
you can do a few trial mixes with various sands to get a good colour
match. Just mix 1 putty : 3 sand and put somewhere to dry out
Anna
--
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
abaker
repairing patches. As has been said already, the mortar needs to be
softer than the stone/brick else it will cause more damage to that
material than vice versa. I would also be tempted to use lime on
anything damp - yes it will allow more moisture in but will also allow
the fabric to shed its moisture in warmer weather.
Purchasing lime can be expensive, only because of the delivery
charges. However it will last indefinitely so long as it is kept from
freezing and is kept in an air-tight container, so is always useful to
have around. Purchase a tub of lime putty and get some sand from a
builders merchant. Mix them yourself.
Mike Wye, Ty Mawr and the Lime Centre (Winchester) are all good
sources (Google them).
On 7 Feb, 18:36, Tansyta...@freeukisp.co.uk (Anna Kettle) wrote:
> On Wed, 07 Feb 2007 17:10:12 +0000, The Natural Philosopher <a...@b.c>
meow...@care2.com
such as B&Q, but not wickes. Its hydrated bagged lime.
There are 2 ways to use it
1. Mix lime to a sloppy putty with water, cover it airtightly, leave
it at least a day, then mix with sand to use.
2. Mix dry lime powder and sand 3:1, add water and use right away.
When the mortar is green, ie solid but not hard, brush the surface to
remove excess whiteness. This exposes the aggregate.
Lime has a few advantages over cement, and the disadvantage of slow
setting. It should not be frosted while setting, so exterior lime work
is usually left till a bit later in the year, or covered with a sheet
for a few days if frost is expected.
Dont mix cement in with lime, as most cement:lime mix ratios are prone
to cause premature failure.
Forget the posted tubs of expensive lime mortar, there's always
someone willing to pay more for something. Lime is cheap.
NT
The Natural Philosopher
> Lime is available from any builders merchants, and many diy sheds,
> such as B&Q, but not wickes. Its hydrated bagged lime.
>
> There are 2 ways to use it
> 1. Mix lime to a sloppy putty with water, cover it airtightly, leave
> it at least a day, then mix with sand to use.
>
> 2. Mix dry lime powder and sand 3:1, add water and use right away.
>
> When the mortar is green, ie solid but not hard, brush the surface to
> remove excess whiteness. This exposes the aggregate.
>
> Lime has a few advantages over cement, and the disadvantage of slow
> setting. It should not be frosted while setting, so exterior lime work
> is usually left till a bit later in the year, or covered with a sheet
> for a few days if frost is expected.
>
> Dont mix cement in with lime, as most cement:lime mix ratios are prone
> to cause premature failure.
>
Thats probably true on extreme situations, but my mixes have all stood
up well. The advantage of some cement is that it sets to a decent
strength quicker. You don;t want to have to wait three days before you
can add another course.,
> Forget the posted tubs of expensive lime mortar, there's always
> someone willing to pay more for something. Lime is cheap.
>
My sentiments exactly.
Most mortar is only a way of keeping the bricks apart anyway. Ultimate
strength and exact engineering quality is often far less important than
appearance.
hydrated lime in a fairly sandy mix looks pretty authentic. Add a bit of
cement and it also sticks better and is harder..
>
> NT
>
Anna Kettle
wrote:
>meow...@care2.com wrote:
>> Lime is available from any builders merchants, and many diy sheds,
>> such as B&Q, but not wickes. Its hydrated bagged lime.
>>
>> There are 2 ways to use it
>> 1. Mix lime to a sloppy putty with water, cover it airtightly, leave
>> it at least a day, then mix with sand to use.
>>
>> 2. Mix dry lime powder and sand 3:1, add water and use right away.
>>
>> When the mortar is green, ie solid but not hard, brush the surface to
>> remove excess whiteness. This exposes the aggregate.
>>
>> Lime has a few advantages over cement, and the disadvantage of slow
>> setting. It should not be frosted while setting, so exterior lime work
>> is usually left till a bit later in the year, or covered with a sheet
>> for a few days if frost is expected.
>>
>> Dont mix cement in with lime, as most cement:lime mix ratios are prone
>> to cause premature failure.
>>
>
>Thats probably true on extreme situations, but my mixes have all stood
>up well. The advantage of some cement is that it sets to a decent
>strength quicker. You don;t want to have to wait three days before you
>can add another course.,
Lime mortar requires air to set, cement is a very fine powder and
tends to block up the air holes in the mix so you run the risk of
a) poor lime set cos the air cant get to it
and
b) poor cement set cos you didnt put much cement in
After a number of failures with cement/lime mortars English Heritage
commissioned a research profect on this and since then cement/lime
mortars have been banned in work done for EH. Some people like NP have
used cement/lime mixes with no problems but there is a risk of
failure. As others have said, bricklaying is not a very testing
situation cos mostly the mortar is there as a spacer. I wouldnt want
to use a cement/lime mix for rendering a wall
The one exception is a cement lime mortar with plenty of cement in it.
This is actually a cement mortar as the lime is not there to do any
setting. It is there purely as a plasticiser. These days most people
use Febmix instead of lime
>> Forget the posted tubs of expensive lime mortar, there's always
>> someone willing to pay more for something. Lime is cheap.
>>
>
>My sentiments exactly.
>
>
>Most mortar is only a way of keeping the bricks apart anyway. Ultimate
>strength and exact engineering quality is often far less important than
>appearance.
>
>hydrated lime in a fairly sandy mix looks pretty authentic. Add a bit of
>cement and it also sticks better and is harder..
Again its horses for courses. Hydrated lime (not hydraulic lime, thats
something else) can be OK. It MUST be fresh and kept in a dry place.
For bricklaying it can possibly be used from the bag (dunno, never
tried) but for rendering you want something with more plasticity in
which case either
a) Use lime putty mortar
or
b) Mix the hydrated lime and sand and water to make up the mortar,
then store in buckets covered in water and it will turn into lime
putty mortar. The longer you can store it the better. One day is
better than none. One month is good, three months better. This is a
very cheap way of making lime putty mortar, about 1/7th the price but
it requires a bit of advance planning
meow...@care2.com
> On Fri, 09 Feb 2007 00:03:38 +0000, The Natural Philosopher <a...@b.c>
> wrote:
> >meow2...@care2.com wrote:
> >> Lime is available from any builders merchants, and many diy sheds,
> >> such as B&Q, but not wickes. Its hydrated bagged lime.
>
> >> There are 2 ways to use it
> >> 1. Mix lime to a sloppy putty with water, cover it airtightly, leave
> >> it at least a day, then mix with sand to use.
>
> >> 2. Mix dry lime powder and sand 3:1, add water and use right away.
>
> >> When the mortar is green, ie solid but not hard, brush the surface to
> >> remove excess whiteness. This exposes the aggregate.
>
> >> Lime has a few advantages over cement, and the disadvantage of slow
> >> setting. It should not be frosted while setting, so exterior lime work
> >> is usually left till a bit later in the year, or covered with a sheet
> >> for a few days if frost is expected.
>
> >> Dont mix cement in with lime, as most cement:lime mix ratios are prone
> >> to cause premature failure.
>
> >Thats probably true on extreme situations, but my mixes have all stood
> >up well.
I read the research on it and it has nothing to do with extreme
situations. Some non 1:1 lime cement mixes do survive ok, sometimes
they dont. None are reliable other than 1:1 c:l.
The advantage of some cement is that it sets to a decent
> >strength quicker.
Yes, but I dont see how thats relevant to repointing, and the price of
premature failure isnt worth it imho.
>> You don;t want to have to wait three days before you
> >can add another course.,
I dont think he plans to. And you dont with just lime anyway.
> >> Forget the posted tubs of expensive lime mortar, there's always
> >> someone willing to pay more for something. Lime is cheap.
> >My sentiments exactly.
>
> >Most mortar is only a way of keeping the bricks apart anyway. Ultimate
> >strength and exact engineering quality is often far less important than
> >appearance.
>
> >hydrated lime in a fairly sandy mix looks pretty authentic. Add a bit of
> >cement and it also sticks better and is harder..
> Again its horses for courses. Hydrated lime (not hydraulic lime, thats
> something else) can be OK. It MUST be fresh and kept in a dry place.
So I'm always told, but I've used old lime without any problems. Its
true that some old lime could have gone off, just like old cement can,
this can be checked for easily enough though, just put a dot of your
lime mix somewhere and come back when is set. If ok, go ahead & use.
> For bricklaying it can possibly be used from the bag (dunno, never
> tried) but for rendering you want something with more plasticity in
Lime straight from the bag can produce minor surface imperfections,
which arent an issue with repointing.
NT
The Natural Philosopher
No, in that I agree.
>
> The one exception is a cement lime mortar with plenty of cement in it.
> This is actually a cement mortar as the lime is not there to do any
> setting. It is there purely as a plasticiser. These days most people
> use Febmix instead of lime
Yes, also done that. Its a very nice mix. I'ts also WHITER.
>
>>> Forget the posted tubs of expensive lime mortar, there's always
>>> someone willing to pay more for something. Lime is cheap.
>>>
>> My sentiments exactly.
>>
>>
>> Most mortar is only a way of keeping the bricks apart anyway. Ultimate
>> strength and exact engineering quality is often far less important than
>> appearance.
>>
>> hydrated lime in a fairly sandy mix looks pretty authentic. Add a bit of
>> cement and it also sticks better and is harder..
>
> Again its horses for courses. Hydrated lime (not hydraulic lime, thats
> something else) can be OK. It MUST be fresh and kept in a dry place.
> For bricklaying it can possibly be used from the bag (dunno, never
> tried)
Yes. I just shoved it into the mixer with the sand and cement.
but for rendering you want something with more plasticity in
> which case either
>
> a) Use lime putty mortar
> or
> b) Mix the hydrated lime and sand and water to make up the mortar,
> then store in buckets covered in water and it will turn into lime
> putty mortar. The longer you can store it the better. One day is
> better than none. One month is good, three months better. This is a
> very cheap way of making lime putty mortar, about 1/7th the price but
> it requires a bit of advance planning
Good trick.
>
> Anna
Nicknoxx
snip useful lime advice.
Anna, can you recommend a book or course for learning more about
building lime. I've just bought a 17th century listed building and feel
sure it will become essential knowledge?
Thanks
--
Nick Brooks
The Natural Philosopher
repair is three times what it would be if it were not listed..or more.
You probably need a course in carpentry more than anything..unless its
one of the very few brick built 17th century houses.
The other huge bugaboo is the listing people. And the BCO.. who will
often give you completely contradictory restrictions.
A course in anger management and people management skills is recommended ;-)
Nicknoxx
> Nicknoxx wrote:
>> Anna Kettle wrote:
>> snip useful lime advice.
>>
>> Anna, can you recommend a book or course for learning more about
>> building lime. I've just bought a 17th century listed building and
>> feel sure it will become essential knowledge?
>>
>> Thanks
>>
>>
> You will need more than a book on lime mortar.
True but Anna is a known expert in this field.
.be prepared to find every
> repair is three times what it would be if it were not listed..or more.
Oh yes,
>
> You probably need a course in carpentry more than anything..unless its
> one of the very few brick built 17th century houses.
Carpentry skills at the ready.
>
> The other huge bugaboo is the listing people. And the BCO.. who will
> often give you completely contradictory restrictions.
Yes I'm aware there may be conflicts, who takes priority?
>
> A course in anger management and people management skills is recommended
> ;-)
>
WHO ASKED YOUR F****IN' OPINION,EH ? :-0
--
Nick Brooks
Anna Kettle
Hi Nick
"Building with lime" by Michael Wingate & Stafford Holmes is the best
book for an overview and lots of background information
For really basic practical stuff like mixes get Jane Schofield's
leaflet called um "Lime" I think
There are several courses around the country, where are you? I think
the best value courses are two or three days with lots of hands on and
only as much theory as necessary to do the hands on, plus a telephone
helpline for when you get home and encounter real life problems
Nicknoxx
> On Fri, 09 Feb 2007 11:44:40 +0000, Nicknoxx <Nick@6&7.net> wrote:
>
>> Anna Kettle wrote:
>> snip useful lime advice.
>>
>> Anna, can you recommend a book or course for learning more about
>> building lime. I've just bought a 17th century listed building and feel
>> sure it will become essential knowledge?
>>
>> Thanks
>>
>>
>> --
>> Nick Brooks
>
> Hi Nick
>
> "Building with lime" by Michael Wingate & Stafford Holmes is the best
> book for an overview and lots of background information
>
> For really basic practical stuff like mixes get Jane Schofield's
> leaflet called um "Lime" I think
>
> There are several courses around the country, where are you? I think
> the best value courses are two or three days with lots of hands on and
> only as much theory as necessary to do the hands on, plus a telephone
> helpline for when you get home and encounter real life problems
>
> Anna
Hi Anna
Thanks for that. I'll look out the books. I'm near Bath
--
Nick Brooks
Anna Kettle
Hi Nick
Ty Mawr Lime in South Wales is probably the best place for courses
then. Lovely people, very inspirational!
meow...@care2.com
Nicknoxx
--
Nick Brooks
2001 SV650
nick at sixandseven dot net
Nicknoxx
> Hi Nick
>
> Ty Mawr Lime in South Wales is probably the best place for courses
> then. Lovely people, very inspirational!
>
> Anna
Thanks I will.
--
Nick Brooks