Stripping exterior render

[Gareth Hughes]

You might like to have a look at the pages I've put up on our site - http://www.heritage-house.org/quinton.html- this was a stone built cottage, much like you describe. Everyone said after we removed the render, that the cottage would need to be re-rendered in lime. We left the soaked stone, which was so soft you could push your finger into it - for nearly 12 months. We sprayed with lime water (just lime putty diluted down lots...!) which allows a bit of lime to get into the grain of the stone and form a protective lattice of calcite crystals. The walls, 2 years later are rock hard, and have defied all attempts by experts to convince the owners to re-render. I don't see any reason for doing so- I recently set up a demonstration, and pressure washed the wall in one area - not a grain of sand was moved. The house is bone dry, warm as toast, and everyone is happy with the exception of the chemical damp proofing contractors who didnt get a job..!

Pete

Well, at the risk of being the other unhappy person:

1. The jury is very definitely out on the long-term benefits of "lime watering". It appeared to work at Wells Cathedral, but there seems to be little scientific reason why it should.

2. The cottage, as "restored", no longer looks anything like it would have done at any previous point in its life, having become a particular late-twentieth century conception of what an old cottage should look like, rather than an honest and worthwhile piece of repair.
Externally it is a "quaint" but utterly inauthentic mish-mash of stone and brick patching, which would have always been covered with render, at least as soon as the first areas of brickwork were added into the mix. Note how the "design" - the arrangement of openings and the overall proportions - are now lost in a patchwork of different materials.
In this, and similar, cases it's not just a question of the technical performance of the building, but one of authenticity.
Internally, the exposed "Flintstones" style rubble walling would absolutely horrify all of the previous occupants. In addition, a number of interesting-looking features have been lost completely by stripping back too far.

3 out of 10, I'm afraid (mostly for resisting the DPM merchants)

Oh, and if you wish to advertise the services of your building company (which your post comes close to doing) I suggest that there are more appropriate parts of the site where that can be done, rather than on this forum.

 

[bournonite]

Just watch the so called experts - there arent many! I'm a geologist by background, with specialised knowledge in geochemistry, so if anyone can talk about rock, I can - you might benefit from taking a sample of your stone, and just letting it dry out for a week or two inside - don't try to dry it too quickly.. failing that - send me a lump and I'll have a look.
From a humerous angle - have a look at a mate of mine's site: http://www.konrad-fischer-info.de/2auffen.htm - he's hilarious - but also very clever!

Pete

 

[bournonite]

Well, at the risk of being the other unhappy person:

1. The jury is very definitely out on the long-term benefits of "lime watering". It appeared to work at Wells Cathedral, but there seems to be little scientific reason why it should.

2. The cottage, as "restored", no longer looks anything like it would have done at any previous point in its life, having become a particular late-twentieth century conception of what an old cottage should look like, rather than an honest and worthwhile piece of repair.
Externally it is a "quaint" but utterly inauthentic mish-mash of stone and brick patching, which would have always been covered with render, at least as soon as the first areas of brickwork were added into the mix. Note how the "design" - the arrangement of openings and the overall proportions - are now lost in a patchwork of different materials.
In this, and similar, cases it's not just a question of the technical performance of the building, but one of authenticity.
Internally, the exposed "Flintstones" style rubble walling would absolutely horrify all of the previous occupants. In addition, a number of interesting-looking features have been lost completely by stripping back too far.

3 out of 10, I'm afraid (mostly for resisting the DPM merchants)

I won't get particularly drawn on this, other than to say that it always amazes me how every time someone actually does a decent job (we've been showered with praise from university, archeology, planning, conservation and several other professional bodies, plus awards) SOMEONE has to get their nose out of joint and poke scorn at it - probably because they arent capable of doing it themselves - keep your quasi criticism and smug comments to yourself until you know more - we have detailed research including very early photos which show exposed stone everywhere, and documented personal reminiscenses going back even further. There is NO evidence that it was ever rendered or plastered with the exception of the 1940's cement episode which wrecked the place. The stone had been limewashed inside - that was it. The openings were left at the request of conservation, who were at pains to preserve authenticity. Interesting looking features lost - I wonder what - 90% of the interesting features were cast in concrete and neither us, nor conservation or archaeology were of the informed opinion that any worthwhile fabric would be lost by stripping, having been there and studied it at length before starting work - -(As I suppose you were..) and the approach was mapped out as a team. Your comments about it not being honest or worthwhile beggar belief - I suppose you can quote a set of rules as to what Honest, or Worthwhile should be?? For the project team, it was a case of preserving the fabric, and doing nothing more or less, except whatever was necessary to ensure the inside was liveable. As for your subjective opinions on what the previous occupants would live with - again - anecdotal evidence was that it was exactly what they DID live with, in a factory environment. Sorry mate, don't spout off whan you havent got facts to hand - I gave up spending time on this otherwise excellent forum when nemesis was around - dont suppose your other name is nemesis?

 

[Gareth Hughes]

Well, at the risk of being the other unhappy person:

1. The jury is very definitely out on the long-term benefits of "lime watering". It appeared to work at Wells Cathedral, but there seems to be little scientific reason why it should.

2. The cottage, as "restored", no longer looks anything like it would have done at any previous point in its life, having become a particular late-twentieth century conception of what an old cottage should look like, rather than an honest and worthwhile piece of repair.
Externally it is a "quaint" but utterly inauthentic mish-mash of stone and brick patching, which would have always been covered with render, at least as soon as the first areas of brickwork were added into the mix. Note how the "design" - the arrangement of openings and the overall proportions - are now lost in a patchwork of different materials.
In this, and similar, cases it's not just a question of the technical performance of the building, but one of authenticity.
Internally, the exposed "Flintstones" style rubble walling would absolutely horrify all of the previous occupants. In addition, a number of interesting-looking features have been lost completely by stripping back too far.

3 out of 10, I'm afraid (mostly for resisting the DPM merchants)

I won't get particularly drawn on this, other than to say that it always amazes me how every time someone actually does a decent job (we've been showered with praise from university, archeology, planning, conservation and several other professional bodies, plus awards) SOMEONE has to get their nose out of joint and poke scorn at it - probably because they arent capable of doing it themselves - keep your quasi criticism and smug comments to yourself until you know more - we have detailed research including very early photos which show exposed stone everywhere, and documented personal reminiscenses going back even further. There is NO evidence that it was ever rendered or plastered with the exception of the 1940's cement episode which wrecked the place. The stone had been limewashed inside - that was it. The openings were left at the request of conservation, who were at pains to preserve authenticity. Interesting looking features lost - I wonder what - 90% of the interesting features were cast in concrete and neither us, nor conservation or archaeology were of the informed opinion that any worthwhile fabric would be lost by stripping, having been there and studied it at length before starting work - -(As I suppose you were..) and the approach was mapped out as a team. Your comments about it not being honest or worthwhile beggar belief - I suppose you can quote a set of rules as to what Honest, or Worthwhile should be?? For the project team, it was a case of preserving the fabric, and doing nothing more or less, except whatever was necessary to ensure the inside was liveable. As for your subjective opinions on what the previous occupants would live with - again - anecdotal evidence was that it was exactly what they DID live with, in a factory environment. Sorry mate, don't spout off whan you havent got facts to hand - I gave up spending time on this otherwise excellent forum when nemesis was around - dont suppose your other name is nemesis?

No, but I can see why she didn't like you. How charming you are, in your first reply to me.

I see you're a geologist. That might give you some basis for making claims about the scientific performance of certain stones, and their treatment from a technical point of view. (Even when, as with limewatering, there's little real support for it)

I'm an architect, that gives me some right to make aesthetic judgements, as for example in the matter of the Flinstones style interior you're so proud of creating.

But I expect craftsmanship from a builder, for which I will respect them, not lip, for which I won't.

This would be the building you referred to in 2007 as:

We're just about to start work on an old nailers cottage in Birmingham - could be as old as 1500's - but listed grade 2 as a 'wonderful example of kentish rag stonework'...When I pointed out that kentish rag was something found in kent, not birmingham...

, followed by the comment that:

Dont you think it makes a mockery of listing if this is the sort of incompetent muppet that goes out listing buildings???

, whereas the list description, as quoted here:
http://www.qlhs.org.uk/conservation/nailers-cottage-2/nailers-cottage-2.htm
(Which also includes a photo of an obviously rendered cottage, in the 1930s, so before your "disastrous cement episode") actually makes no mention of "Kentish rag".
Unfortunate that the same page describes the removal of the render as "an historian’s delight" but that's local history groups for you, so often (but not quite always) full of misdirected enthusiasm.

 

[Lime]

I think this is a nightmare thread.

If it wasn't for my sense of humour I'd be crying.

 

[DaveBrigg]

Hi JoceandChris, there are a few of us here from Lincolnshire now, though it sounds like we are further north. I stripped the cement render off our house last summer for the same reasons you have given. Ours is all brick, which was also sodden in places and at the point of disintegration around all the downstairs windows. The advice to remove slowly and carefully is good; one of the final patches to be taken off revealed a window lintel that had turned to dust, and I was left on the ladder holding up part of our son's bedroom wall until a prop could be found.
I started with a hammer and bolster, but soon progressed to a hammer drill and chisel. Used with care, almost parallel with the wall, it saved so much time that without it I think I would still be there now. I bought a cheap one on offer from Screwfix, and it did the job well. The time-consuming job was shovelling up the cement afterwards and disposing of it, although fortunately someone local needed hardcore. We were briefly tempted to keep the brick finish, but the CO pointed out that this had been patched, altered, had windows cut in or taken out and new courses added on top, and would have been rendered to hide the mess. Aside from the good advice you have had already, can I add that you ahve done well not to rush in and try to strip the whole place at once. For most of us here, this work is a learning process, and I atrribute my slow progress to a desire not to make mistakes (despite what my wife says).
We had our house lime rendered by a professional from Grimsby and were very pleased with the job. I assume that as long as joints were kept to corners (internal if possible) it would be possible to render the house in stages, especially if you are going to limewash afterwards. However, the process is fairly intrusive, with scaffolding required, deliveries of tonnes of lime and sand, downpipes removed and quite a lot of clearing up afterwards. It may be easier and cheaper in the long run to get it out of the way in one go.
Good luck.

 

[Jon Maine]

You might like to have a look at the pages I've put up on our site - http://www.heritage-house.org/quinton.html- this was a stone built cottage, much like you describe. Everyone said after we removed the render, that the cottage would need to be re-rendered in lime. We left the soaked stone, which was so soft you could push your finger into it - for nearly 12 months. We sprayed with lime water (just lime putty diluted down lots...!) which allows a bit of lime to get into the grain of the stone and form a protective lattice of calcite crystals. The walls, 2 years later are rock hard, and have defied all attempts by experts to convince the owners to re-render. I don't see any reason for doing so- I recently set up a demonstration, and pressure washed the wall in one area - not a grain of sand was moved. The house is bone dry, warm as toast, and everyone is happy with the exception of the chemical damp proofing contractors who didnt get a job..!

Pete

Well, at the risk of being the other unhappy person:

1. The jury is very definitely out on the long-term benefits of "lime watering". It appeared to work at Wells Cathedral, but there seems to be little scientific reason why it should.

2. The cottage, as "restored", no longer looks anything like it would have done at any previous point in its life, having become a particular late-twentieth century conception of what an old cottage should look like, rather than an honest and worthwhile piece of repair.
Externally it is a "quaint" but utterly inauthentic mish-mash of stone and brick patching, which would have always been covered with render, at least as soon as the first areas of brickwork were added into the mix. Note how the "design" - the arrangement of openings and the overall proportions - are now lost in a patchwork of different materials.
In this, and similar, cases it's not just a question of the technical performance of the building, but one of authenticity.
Internally, the exposed "Flintstones" style rubble walling would absolutely horrify all of the previous occupants. In addition, a number of interesting-looking features have been lost completely by stripping back too far.

3 out of 10, I'm afraid (mostly for resisting the DPM merchants)

Oh, and if you wish to advertise the services of your building company (which your post comes close to doing) I suggest that there are more appropriate parts of the site where that can be done, rather than on this forum.

I agree, we had rotten stone here. We replaced it with new as indeed our predecessors would have not mucking about with a witches potion which has no long term record of success and the potential for expensive remedial in the future.

Understanding detailing for historic property is a time learnt skill, not picked up in anyone's spare time quickly unless you are an incredibly observant natural.

I have taken 25 years to get to where I have in the trade, It is unfortunate that people can buy a van read up on a forum like this one and go into competition with me because they are qualified in another field? And then to top it off to put a link to their commercial site? Well I have a site listed in my profile, I am a contractor and it is certainly a non commercial site. I read the rules.

Please anyone reading if you wish to advertise do it somewhere else.

 

[Gareth Hughes]

Hi JoceandChris, there are a few of us here from Lincolnshire now, though it sounds like we are further north. I stripped the cement render off our house last summer for the same reasons you have given. Ours is all brick, which was also sodden in places and at the point of disintegration around all the downstairs windows. The advice to remove slowly and carefully is good; one of the final patches to be taken off revealed a window lintel that had turned to dust, and I was left on the ladder holding up part of our son's bedroom wall until a prop could be found.
I started with a hammer and bolster, but soon progressed to a hammer drill and chisel. Used with care, almost parallel with the wall, it saved so much time that without it I think I would still be there now. I bought a cheap one on offer from Screwfix, and it did the job well. The time-consuming job was shovelling up the cement afterwards and disposing of it, although fortunately someone local needed hardcore. We were briefly tempted to keep the brick finish, but the CO pointed out that this had been patched, altered, had windows cut in or taken out and new courses added on top, and would have been rendered to hide the mess. Aside from the good advice you have had already, can I add that you ahve done well not to rush in and try to strip the whole place at once. For most of us here, this work is a learning process, and I atrribute my slow progress to a desire not to make mistakes (despite what my wife says).
We had our house lime rendered by a professional from Grimsby and were very pleased with the job. I assume that as long as joints were kept to corners (internal if possible) it would be possible to render the house in stages, especially if you are going to limewash afterwards. However, the process is fairly intrusive, with scaffolding required, deliveries of tonnes of lime and sand, downpipes removed and quite a lot of clearing up afterwards. It may be easier and cheaper in the long run to get it out of the way in one go.
Good luck.

Sound advice, and from someone in the same position as the original poster.

 

[Lime]

I must be a glutton for punishment because I have just re-read the thread.
I'm horrified that rendering is being removed with such gusto that holes are being created that penetrate into the depths of the house.
That is where the skill of the operator is all important.
It can take a delicate touch and a lot of patience to do a good job with little damage.
Knocking the house down just because it is old, weak and neglected is not what owning period property should be about.
The innocent comment about listing had me smiling in spite of the serious aspect of the remark.

Then we are shown another old house stripped of it's heart, exposed and modernised being held up as good example of what old houses should be subjected to.
God help us!
If all old houses were to be prey to such treatment there'd be nothing left.

Come back Nemesis, all is forgiven!

 

[MdB]

I'm horrified that rendering is being removed with such gusto that holes are being created that penetrate into the depths of the house.

Please hold of your horror until you know all the facts. I had exactly the same think in my house, I removed some very unattached render to find I could see into the living room. In this case it was due to a piece of wood embedded into the outside wall which had rotted completely underneath the cement render. Not much you can do about this until you actually start the work as it was all hidden.

 

[Lime]

Yes I'm aware that many unforeseen aspects may be revealed.
It was the

I'm scared about what I did today

that worried me.

 

[Konrad Fischer]

"I have been advised that [cement render] is ... the cause of our damp"

Maybe, but most not be. Often it is an animal based big load of nitrate salt in the walls which is the only reason for all given damp problems. Test it by using nitrate test strips. Very cheap and easy use for all DIY-loving home owners on the battle field of so famous experts :wink:

Good luck!

Konrad

 

[Lime]

"I have been advised that [cement render] is ... the cause of our damp"

Nitrates do play a part, particularly in older more rural buildings, but cladding an absorbent and perhap hygroscopic wall in a shell of cement that prevents evaporation is not good.
The damp will build up and cause further problems.
Often the same cement cladding, that was originally applied to keep water out, allows the rain in through cracks etc then prevents it evaporating so water builds up in the wall.

A stiff inflexible carcass of cement attached to an otherwise flexible wall (often lime-based) causes structural damage to the building too.

 

[Stephen]

"I have been advised that [cement render] is ... the cause of our damp"

Often it is an animal based big load of nitrate salt in the walls which is the only reason for all given damp problems.

Konrad

That is a rather sweeping statement and not one I can agree with. There are many possible causes of damp, or the staining of what seems to be dampness and salts can be a cause of some problems. However, to state that it is the cause for "all given damp problems" cannot be justified.

I would agree that the matter needs careful consideration and investigation before action. However, in my experience cement render is a common cause of dampness being trapped in a wall structure and therefore leading to a build-up of damp over time that can eventually cause problems. I have been involved in many cases where once the render has been removed the wall dries out - nothing to do with salts.

Without knowing the precise details of this case I would not wish to give definitive comment, but in general terms it is not usually a bad thing to remove cement render from an old building. Subject to the usual caveats about being careful and keeping it to manageable areas, considering carefully what is to go back, getting consents (if appropriate), etc, etc, etc; I would have no particular problem with removal of cement render.

On the issue of whether the building was previously rendered a simple check is to look at window and door perimeter details. If the perimeter details are proud of the stone wall finish it is likely that the wall was intended to have a render finish to it. If the perimeter details are nearly flush with the stone then maybe it was meant to be left exposed or only coated with limewash.

Stephen

 

[Gervase]

You might like to have a look at the pages I've put up on our site - http://www.heritage-house.org/quinton.html- this was a stone built cottage, much like you describe. Everyone said after we removed the render, that the cottage would need to be re-rendered in lime. We left the soaked stone, which was so soft you could push your finger into it - for nearly 12 months. We sprayed with lime water (just lime putty diluted down lots...!) which allows a bit of lime to get into the grain of the stone and form a protective lattice of calcite crystals. The walls, 2 years later are rock hard, and have defied all attempts by experts to convince the owners to re-render. I don't see any reason for doing so- I recently set up a demonstration, and pressure washed the wall in one area - not a grain of sand was moved. The house is bone dry, warm as toast, and everyone is happy with the exception of the chemical damp proofing contractors who didnt get a job..!

Pete

But when is it going to be finished? It looks from the pictures as though there's a lot of render and plaster still needed. Or did the owner specifically want a "stage-set" pastiche of an old house?
Interesting that you seem to specify hydraulic lime for all work. Any particular reason?

 

[Konrad Fischer]

"to state that it is the cause for "all given damp problems" cannot be justified."

Correct. But:

Please read my whole sentence and regard my bad germanenglish (pardon). The complete sentence:

"Often it is an animal based big load of nitrate salt in the walls which is the only reason for all given damp problems." - shortly said: Often nitrate salt in the walls is the only reason for all given damp problems.

Often is not everytime and everywhere! "Given" means given in a salt loaded building.

And there are lots of old town buildings (at least in Germany) salt loaded in the cellars and ground floors. We had twice hungry people living (and partly starving) there after WW's and they had animals (chickens, goose, ...) in their buildings to get some eggs, milk, meat etc. In war time and after war time lots of town buildings had been overcrowded and not all inhabitants - as my own parents, living in Berlin and Munich then, told me - could use the water toilet all the time (during bombing), which partly was in the courtyard outside. In the 19th and before it was very common to live with animals also in the towns (we say "Ackerbürger") and please regard all the time when horses did the transports and not cars ...

Best regards
Konrad

PS. I restored over 400 listed buildings in Germany (no, I'm not proud to announce) and know at least to make some difference :wink:

 

[Stephen]

Konrad

I take your point and I think the way you put it did convey the wrong message. However, you seem to have cleared that up.

What we need to be very careful of is applying findings and experience from one country (or even region in a country) and blindly applying it to other regions. I understand what you say about your experience in Germany. In the UK, although houses in the Mediaeval period did have animals in them for the past few centuries most houses did not (except in some rural areas).

We do have a lot of converted farm buildings (stables, etc) where salt deposits are a major issue. However, salt deposits in houses (buildings that have always been houses and not had animals in them) generally is perhaps not as prevalent here as you have found in Germany.

We need to be aware of the potential for salt problems, but here I think we should not overstate the issue of salts. In the situation described in this thread I would be surprised if salts were found to be a factor.

In the UK salt is becomming a problem mainly where properties are alongside roads and in winter the roads are sprayed with a grit/salt mix. If this splashes into the walls it can cause problems. Once again however, the problem is not necessarily widespread.

Stephen

 

[Konrad Fischer]

Dear Stephen,
I didn't want to start a philosopical discussion about the situation of german and english salt loads by animals in houses. Maybe the englishmen (have never been in England and know only from TV, Shakespeare, Sherlok Holmes, Monty Python etc.) are not used to dogs and cats in their houses as the germans did. And regarding the horses etc. in the 19th and earlier a lot of german town houses had stables which are now used as residence for people.

Anyway, my TIP (say "message") was to make the DIY-test with the nitrate strips. Costs nearly nothing and can improve the knowledge and repair stratgy very much. Sth wrong with this?

Best regards
Konrad

 

[Gareth Hughes]

Dear Stephen,
I didn't want to start a philosopical discussion about the situation of german and english salt loads by animals in houses. Maybe the englishmen (have never been in England and know only from TV, Shakespeare, Sherlok Holmes, Monty Python etc.) are not used to dogs and cats in their houses as the germans did.

There are certainly dog and cat lovers in England, and always have been. But they don't and didn't allow their pets to pee indside their homes to such an extent that years or centuries later it would have a remotely significant effect.

 

[Jon Maine]

PS. I restored over 400 listed buildings in Germany (no, I'm not proud to announce) and know at least to make some difference :wink:

In the last 15 years I have taken 2 buildings at risk off the register, 400 is bloody good going, I dont know if I have even been in 400 yet let alone worked on more than 30 or 40