for People with a Passion for Period Property
Ask an Agony Uncle!
Stephen Boniface - Stephen Boniface specialises in building conservation providing multi-disciplinary consulting services. He is Chairman of the Building Surveying Faculty and member of the Residential faculty. He serves on the RICS Building Conservation Forum Board and is the 'Agony Uncle' on the Period Property UK website (

Ask our Agony Uncles ...

You can write to our panel of experts free of charge on any subject, providing it's got something to do with Period Properties.

Our experts are all specialists in matters directly involved with older properties. So, if you have a problem with an older building - or if you think you might have a problem - ask an Agony Uncle...

o Thatched cottage extension advice Kathleen Harris (Hampshire)
o How do I find out if a property is listed? Kingsley Arnold (West Glamorgan)
o Should I use a DPC or Electro Osmosis to solve the damp in my house? Dean Young (County Antrim)
o Built up driveway causes damp wall Simon Slater (Surrey)
o Can conservation officers dictate the style & size of our wall? Mr Carne (Essex)
o How should I insulate my Georgian slate roof? Tim Johns (Scunthorpe)
o I've got DeathWatch Beetle, Help! Simon Harvey (Colchester)
o Patchy plastering drives me mad! Michael Werner (London)
o What questions should I ask & what should I look for when buying a thatched cottage? Andy Godman (Pinner)
o Possible Lead paint gives cause for concern Diane Brown (Essex)
o Internal chimney brickwork crumbling due to damp Paul Grimshaw (York)
o What mortar should I use to rebuild flint wall? Paul Buchanan (Kent)
o Re-pointing a stone farm house Lynne Larkman (Oxfordshire)
o How do I finish flagstones to halt dust and highlight their colour?

Robert Quail (Preston)
Matthew Hayes (Gwent)
Keith Munro (Somerset)
Patrick Sorrell (Essex)
Angela Riddle (Somerset)


SUBJECT: Thatched cottage extension advice
FROM: Kathleen Harris (Hampshire)
We have recently purchased a 300 year old thatched cottage. The cottage has a single storey extension which acts as a kitchen and bathroom we would like to take down this extension and build a larger two storey dormer style extension which would be sympathetic to the original property. The cottage is not listed but we have been contacted by English Heritage advising us that the local conservation officer has brought the cottage to their attention. EH would like to take a look to see if they would be interested in listing the property. We have been told that if we apply for planning permission the local council will ask the conservation officer if they have any objections (even though we are not in a conservation area) and that it is doubtful that they would agree to a two storey extension - is this correct, do you have any advise on what we should consider when employing an architect to do the drawings. Any advice would be helpful.

Kathleen Harris

This question raises a number of issues. Regardless of whether the building is listed, the fact that it is an old building means that it has to be considered carefully particularly with regard to the techniques used for any extension, etc. There are many pages on this site talking about the incompatibility of modern materials with traditional buildings and this applies whether the building is listed or not.

There is concern that a number of thatched cottages may contain historic thatch to the base coats and a reason English Heritage may wish to inspect the property is to ascertain whether such material exists in this instance. I am aware that Hampshire generally are carrying out a thorough survey of all thatched buildings in the county. It sounds as if English Heritage and the Local Authority are taking a soft approach in this instance. If you apply for planning permission to force their hand on this they could spot list the building anyway.

Whether the building is listed or not it is quite likely that the conservation officer will be consulted on the planning application and his/her views taken into account. Conservation officers are often consulted with regard to aesthetic issues. My suggestion is that you cooperate with English Heritage and the Local Authority. Failure to do so is unlikely to be of benefit.

Your enquiries about a two-storey extension have produced the initial response that one would perhaps expect. Until the officers see a drawing they cannot assess its true impact on the building, etc. They are unlikely to be prepared to give anything other than a very cautious and probably negative response. I certainly believe that you require proper drawings and these ought to be prepared by an architect experienced in dealing with old buildings. It would be sensible to use someone with a good track record of extending listed buildings in this district. The planning and conservation officers may well be able to provide you with some names of architects who have undertaken such work in the area, although you should understand that they are not able to give recommendations.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: How do I find out if a property is listed?
FROM: Kingsley Arnold (West Glamorgan)
I am about to purchase a 300 year old farmhouse which retains many old and unusual features. How do I find out if the property is listed without drawing attention to the property? Also, what is the process which leads to a property becoming listed?

Kingsley Arnold

To find out if a property is listed you could simply telephone the local authority and ask the planning department. You will not need to give your name but you would need to give the address of the property. An alternative is to go to the Records Office at Swindon, where copies of all listing records are kept.

It is not clear why you do not wish to draw attention to the property. It is common for prospective purchasers, surveyors and others to phone up local authorities to find out if a property is listed. Some local authorities actually produce documents identifying all conservation areas and listed buildings in their district.

Regarding the process which leads to the property becoming listed, there are a number of means whereby this can happen. Anyone can submit a suggestion to the Department of the Environment that a property should be listed. English Heritage, the local authorities and the various national amenities societies are then asked to consider the matter and prepare a report. This would be undertaken following an inspection of the property. If there is general agreement a recommendation is then put to the Secretary of State for listing the property at a certain grade.

Sometimes when a planning application is submitted the building comes to the attention of the planning authority and during the course of their consideration they might feel that the property ought to be listed and again a similar process to the above will take place. However, if the property is subject to major works that the authority feel might be inappropriate there is a possibility that it could be spot listed. This is only undertaken in emergency situations to try to protect a building usually from demolition.

The other scenario is if English Heritage are undertaking a thematic or systematic assessment whereby properties of interest might then be discovered and be considered for listing.

Under recent changes, property owners and others do have an opportunity to make representations regarding a property being considered for listing. If a property is listed there are grounds for appealing and/or having it de-listed. You can find more information regarding the processes etc on the English Heritage website.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Should I use a DPC or Electro Osmosis to solve the damp in my house?
FROM: Dean Young (County Antrim)
My property is a stone built house which is 100 years old which has been unoccupied for the past 18 months. The surveyor's report says it requires rising damp treatment. Is it better to inject silicone DPC or Electro osmosis DPC?

Dean Young

Quite simply, in my opinion neither should be considered as the first course of action. I have yet to come across Electro osmosis DPC treatment that has been effective. It is a method of retrospective treatment that I would never recommend personally. Similarly, I cannot remember the last time I recommended injecting a retrospective chemical damp proof course in a building.

Most damp problems can be resolved by general building work once the reason the property is damp has been identified. The property was probably constructed without a damp proof course and has survived most of its life quite satisfactorily without a damp proof course. One therefore has to ask what is causing it to be damp at present. There could be high ground levels, inappropriate materials used on surfaces, etc or there could be leaks. All of these issues need to be very carefully considered and dealt with before any further damp treatment is undertaken. As the property has been unoccupied for so long there is a strong possibility that there is a serious condensation problem and this is another form of dampness that should be considered. Unfortunately, too many surveyors recommend damp treatment as a matter of course without considering the true causes of dampness.

You require advice from someone experienced in dealing with historic buildings.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Built up driveway causes damp wall
FROM: Simon Slater (Godalming, Surrey)
The walls of my kitchen and dining room in my 1680 house are damp on one side, with the cause apparently being high exterior ground levels. The problem is that the ground outside the walls comprises my neighbours' drive, which seems to have been progressively built up over the years. It seems the Solution would be to excavate the drive back down to a level below the floor levels of my house, but this may be difficult to agree. It seems to me that the drive itself should never have been raised so high in the first place given that this has damaged the fabric of a listed building - might I be able to enlist the local authority to help my case?

Simon Slater

The first course of action should be to discuss with your neighbour the possibility of excavating the drive to create a ventilation and drainage channel beside the wall of the building and then to create the drive perhaps with a cantilevered edge to partly disguise the channel. Care should be taken to ensure that the channel is accessible for clearing (leaves etc) and it should be properly drained so that it does not become full of water.

If this approach fails there are works you could undertake internally but they are of a type that cannot be guaranteed to be satisfactory for perhaps more than 5 to 10 years. In any event, some of the works that might need to be undertaken where there are high ground levels could cause other problems of dampness within the wall.

Your local authority are unlikely to be able to assist unless the works to the neighbouring property were subject to a planning or building regulation application and the work has not been undertaken in accordance with the approvals etc. Your only other course of action would be through litigation. You would need to seek advice from a solicitor. See the answer above regarding possible routes of legal advice.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Can conservation officers dictate the style & size of our wall?
FROM: Mr Carne (Ongar, Essex)
We want to build a wall leading up to the entrance gates of our property but the Heritage people have objected to our design and want us to build a wall to their design without giving us a choice. Can they insist that we build the wall to their specification and if we decided to alter their design what would be the implications.

Mr Carne

You do not say whether your property is listed but I suspect it is in a conservation area anyway, hence the requirements to build a wall of design that is considered appropriate in the circumstances.

I know the officers for your district and generally find them to be open to discussion if approached in the right way. I would be surprised if they would impose their design without discussion and consultation. You need to think very carefully about the design of the wall and the gates etc, consider what they have suggested and perhaps try a different design that incorporates elements of both. It is necessary to reach an agreement and this might mean compromise on both sides.

Many property owners do not fully appreciate the impact that walls and gates can have upon the street scene and upon the overall character and appearance of the building itself. I am not suggesting that what you would like to do is inappropriate, as I have no way of knowing what you have proposed, or what the council would prefer. Nevertheless, to build a wall ignoring their advice and without getting appropriate consent etc could lead you into a major legal battle. If the building is listed and you do not obtain consent it would be a criminal offence to proceed with the work.

In any event, there are planning controls over boundary walls and gates above a certain height, etc. The very least a council could do would be to serve an enforcement notice.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: How should I insulate my Georgian slate roof?
FROM: Tim Johns (Scunthorpe)
I own a Georgian property. I am considering renovating its long neglected 3rd storey. What is the best way of insulating its slate roof? There is nothing covering the slates on the underside of the roof currently.

Tim Johns

Slate roofs do not technically require a lining and in any event, linings tend to restrict ventilation, which is vitally important for roofs. The lack of a lining should not be a concern. Whatever form of insulation is considered ventilation above the insulation is important. It might be best to consider a semi-rigid insulating board that can be carefully installed and fixed to battens between rafters leaving a ventilation gap above the insulation. I would not recommend using a spray-on insulation.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: I've got DeathWatch Beetle, Help!
FROM: Simon Harvey (Colchester)
I live in a 500 year old weavers shed and have noticed over the last couple of months a knocking sound coming from the timbers and so assumed beetles. This was confirmed the other week after returning from a week away to find lots of dead 1/4 inch beetles scattered over the room. I was wondering is you could tell me what sort of beetles they are and what needs to be done.

Simon Harvey

From your description it would seem that you have deathwatch beetle. As the property is 500 years old it is probably constructed of oak. I would not recommend simply spraying the surfaces, as this is not usually effective against deathwatch beetle. You must try to identify where the beetles are living within the wood and use either deep penetrating pastes localised in this area or open up and target treat the nest itself. Where you have beetle infestation it usually suggest that the oak is being affected by dampness and you may therefore also have to consider dealing with dampness. On this website there are many pages addressing the issue of dampness and you will probably be aware that conventional treatment is not usually the right approach with historic buildings.

For further advice I suggest you speak with either Brian Ridout (who's site etc can be found through the Building Conservation Directory) or Hutton and Rostron (again who can be reached through the Building Conservation Directory.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Patchy plastering drives me mad!
FROM: Michael Werner (London)
So far I have surfed the net in vain for advice on how to cosmetically treat recently re-rendered and extremely poorly finished patches on the outer front elevation of my house. Being a layman, I am desperate for professional advice on how to rectify the situation.

I am the owner of a period residential building, dating from ca 1875, and which is unique as it is one of eight houses forming a unified terrace with rarely found distinct continental, if not Dutch, architectural features.

Recently I had massive restoration works done, employing an architect and a construction company, in effort to preserve the originality of the building. Despite their help, there is a huge problem - for me at least - in that none of these professionals seem to have the faintest idea of how to rectify the problem as follows:

Crumbling patches of (maybe) original render had to be removed and the bare brick properly treated. Following this, these areas were re-rendered and later on painted. Once the paint had dried, the re-rendered patches have become pronouncedly visible. Absolutely no attempt had been made to match the new with the old surrounding surfaces. Moreover, the re-rendered areas have not been built up to the thickness of the existing surroundings - instead they are visibly recessed. The facade of the building now bears very ugly looking scars, highlighted by the influx of (especially sun) light, defeating the entire intention of restoration.

In an attempt to rectify the situation, I had suggested to apply an appropriate mixture of finer sand and cement in conjunction with the correct bonding material in order build up these recesses and match the surfaces as well as possible. (I had tried this method myself on a very small area, and it appeared to be working ok, except that I should probably have added somewhat more of the bonding compound - using 'Unibond' - as the sand-cement mixture could too easily be sanded off. Nonetheless, following the application of Various layers of 'Keim' mineral paint, the rendered and built up surface matched the original one pretty well).

I suggested investigating this method - or one similar to it. But the professionals appeared to have overruled this suggestion. In an attempt to evade and avoid enveloped remedies, such as matching and building up, they have opted for the easy way out: severely sanding the borderlines and far too widespread areas adjacent to the blemishes. Now, that these areas have also been re-painted it is clear that the blemishes, or scars, have been massively enlarged, spreading over a much wider area than before. The severe sanding, as a means of intentionally avoiding the build-up, has of course not rectified the situation.

The facade in these areas simply looks a mess, and it has become an issue of contention. I shall not rest until the mistakes have been rectified satisfactorily. In order to counteract further bungles and sheer laziness, I am kindly asking for your relay to the professionals how the corrections can be successfully implemented.

Michael Werner

As it seems you are leading towards a dispute with your professional advisers and contractors any reply has to be cautious and subject to a formal inspection from an independent consultant (e.g. architect or surveyor).

Turning to the practical issues, the original material you describe was probably stucco and various mixes were used on buildings during the 19th century. When repairing stucco the first rule is to analyse what is there and try to match it as closely as possible. If different mixes are used and/or original finishes remain alongside patched areas (with no previous paint finish) there will be a different consistency, surface finish, etc. The paint finish will be absorbed at different rates and will give a patchy appearance. Unevenness will appear if old paint is left on a surface and the patch repair is not brought sufficiently forward to allow for the different finish thicknesses. There are a number of possible causes of the problems you experience and there could be more than one problem.

The use of modern materials and techniques (such as unibond) might resolve the problem and could result in a satisfactory appearance for the time being. My concern is the question of whether such modern methods will stand the test of time and remain 'compatible' with the original material. In particular, when re-decoration is required in future the use of these modern materials may make if more difficult to achieve a satisfactory finish.

Although you have provided much detail this really is a matter upon which you require independent advice from someone who could actually come and have a look at the problem. The architect or surveyor appointed should be someone experienced in dealing with historic buildings. More specifically someone experienced in dealing with stucco. As the matter may become litigious the specialist should also be someone conversant with acting as an Expert Witness in litigation under the Civil Procedure Rules.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: What questions should I ask & what should I look for when buying a thatched cottage?
FROM: Andy Godman (Pinner)
I am considering buying a thatched cottage which dates back to the 16th Century. What things should I look out for / questions should I ask during my initial viewing. What are the potential problems I may face during ownership over a more modern property.

Andy Godman

It is assumed that the cottage is listed. You do not say what construction the rest of the building is formed from (timber frame, brick, etc). The first thing I would urge is that you obtain professional advice from someone experienced in surveying historic buildings. Someone who can analyse the condition of the property and advise properly on what repairs may be necessary, the urgency (or otherwise) of such work and whether past works/materials are, or are likely to become, a problem. In the meantime I can give a few pointers.

Things to ask the vendor would include details about past works including sight of any documentation, details of who undertook the work, who supervised the work and whether appropriate consent were properly obtained for the works (if required)?

With regard to the thatch you should look to see if it has a ragged poor finished appearance or whether it is relatively neat and tidy. Are there any obvious holes or lengths of the material that have come adrift, is the ridge reasonably intact, are the details around the chimney generally sound, are the lines of fixings visible on the surface, are then any significant dips in the surface or any other obvious unevenness?

What you may or may not need to do with regard to the thatch will depend on a number of factors including the nature of the material itself. There are differing views within the thatching world about different thatch materials and, as with many industries, there are a number of vested interests that can skew advice given. As you are based in Pinner and are probably buying somewhere in the northern Homes Counties or East Anglia region I suggest that you contact the East Anglia Master Thatchers Association to find a suitable thatcher in the district to inspect the thatch and advise further. You should expect to pay for this advice, as you are looking for a professional independent opinion.

With regard to the main structure of the building you should look for signs of degradation, cracking on surfaces and particularly recent defects. In your discussion with the vendor you should identify whether works in the past have been undertaken using conventional modern materials or whether they have use of traditional materials. If modern materials have been used there could be hidden problems or you may at least have to consider reversion to traditional materials at some future date. I am thinking particularly of renders and plasters to surfaces.

Most historic buildings will exhibit signs of past wood boring beetle infestation to timbers. It can be very difficult to identify a recent or ongoing infestation attack and this is something best left to a professional, but one with no vested interest in the recommendations made.

There may be signs of dampness but look for other problems such as obvious leaks, high ground levels or lack of ventilation to sub floor voids (if any). These are matters that you can generally check for yourself.

You should gain a general impression of whether the building is well maintained, whether it appears to have been "tarted up" for sale, or whether it has been neglected, etc. Anyone buying a property of such age should seek further professional advice before committing themselves to a purchase. Any survey undertaken should be carried out by a surveyor with appropriate experience in the survey of listed and historic buildings. The RICS conservation group can assist with this and to locate a surveyor near to the property you could telephone the executive for the RICS Building Conservation Forum (Mr Kieron Higgs on 020 7222 7000). You should ensure that the surveyor is experienced in dealing with thatch. Some surveyors are of course listed on this website or can be reached via the Building Conservation Directory.

Your final point is whether there are any particular problems you might face that are different to owning a modern property. Historic buildings are constructed with materials and techniques no longer used. There are many aspects of the building that will be different. There is of course a greater risk of problems being hidden and being uncovered/discovered at a future date. With any historic building this is a risk. I always advise clients buying historic building to avoid the temptation of exploring too deeply simply for the sake of it. These buildings ought to be tackled in a properly programmed manner. Many buildings can be dealt with by phasing the works over a number of years and tackling work in manageable sections. By manageable I refer not only to the practicalities but also financial matters. It is rarely appropriate to simply open up a historic building unless there is a readily identifiable problem or genuine suspicion that there is a hidden defect requiring urgent action.

The most common problem I find is the use of incompatible modern materials on historic buildings. All buildings deteriorate with age, which cannot be stopped completely. However, what we do or do not do to a building can accelerate or decelerate this process. Once a building has been properly repaired as necessary then it is simply a matter of keeping it well maintained. Many of the things that give character to a historic building could be regarded by some as a disadvantage - for example sloping floors, walls, windows and doors etc not square, springy floors, creeks and noises, etc.

Provided windows and doors are properly draught-proofed (or perhaps have secondary glazing installed) there is no reason to suspect a historic building of being particularly cold. In fact many owners advise me that they find them warmer than modern buildings - or at least the comfort level is better. The only word of warning on this is to ensure that you maintain generally good ventilation levels throughout the building.

Any building should be regularly maintained whether historic or not. Constant maintenance and repair is the best way to look after any building.

The use of traditional materials and specialist craftsman can involve higher costs. However, this is often balanced by adopting the philosophy of minimum intervention and doing only what repair is strictly necessary.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Possible Lead paint gives cause for concern
FROM: Diane Brown (Clacton on Sea, Essex)
I have an Edwardian villa (1908), with all the original door frames/architrave, skirting boards etc intact. The problem is they have never been stripped since they were originally installed, and are now at the stage where there is just too much paint on them and it is spoiling their appearance. It also seems to be very brittle, so that every time one of my children knocks against the paintwork, yet another large chip of paint falls off. Judging by the age of the house, I would expect that there is lead paint lurking underneath all the modern white gloss. Please would you advise the best way to deal with this as we would really like to strip all the paint off back to bare wood and start again, but are worried about disturbing the lead paint.

Diane Brown

You are quite correct to be concerned about the possibility of lead paint and in this instance it is almost inevitable that there will be lead paint on the surfaces.

If you intend to take the paint surface off completely then you should have these professionally dealt with. If you are simply going to prepare the surfaces for re-painting by removing some of the uppermost layers you must use a wet sanding system to minimise the amount of dust created. It is the dust that is the problem and needs to be avoided. If you undertake any of the work yourself (not advised) you must wear protective masks, etc. The debris must be properly bagged up and disposed of at appropriate amenity refuse sites.

I trust you find these initial comments of some use, but please seek further specialist advice (see the Building Conservation Directory or the 'Seeking Specialists section of this site) before embarking on such work.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Internal chimney brickwork crumbling due to damp
FROM: Paul Grimshaw (York)
I have an 1850s town house that has an exposed brick chimney breast running through he heart of the building. Near the foot of the breast on the lower floor the bricks are omitting kind of salty residue which also appears to be rotting the bricks. Where the salt appears the bricks are crumbling over time. Rather worryingly this appears to be rising on one side of the fireplace. Do you have any ideas (a) what this might be (b)how to stop it! It has been present ever since we moved in 4 years ago but now appears to be getting worse.

Paul Grimshaw

The one thing you do not tell me in your query is the nature of the floor. However, the problem is simply where dampness is evaporating from the brickwork and leaving a salt deposit. The crystallisation of the salts will sometimes cause deterioration of the brick faces. This is not an uncommon problem.

Such defects are usually allied to the insertion in the past of a concrete floor and/or the use of modern cement mortar for pointing the brickwork etc. Concrete floors tend to cap normal ground moisture rather than allowing it to breath through (which would happen with traditional breathable floors or where there is a suspended timber floor with a ventilated void). The result is that the moisture will find another route and often it means that the chimney and/or perimeter walls act as wicks and the bases of these areas become supercharged with moisture. My preferred solution is to take up the concrete floor and revert to traditional breathable floors or a ventilated void beneath the timber floor. This might not be a practical solution in your situation.

If the brickwork has been pointed with modern cement mortar it might be best to rake this out and replace it with traditional lime mortar to allow the brickwork to breath and at least the pointing will be the sacrificial element rather than the brickwork (as at present). I notice that you are located in York where there have been flooding problems in recent times. It is quite likely that ground moisture is high and this has exacerbated the problem hence the fact that you say the problem has worsened recently.

The property would not always have been damp and this problem would not have existed in the past. You have to look at what has changed to lead to the present problems. I suggest you look at whether there have been major changes such as replacing floors or re-pointing but in addition to this you have got the problem of rising water tables within the ground beneath the building, which you can do nothing about.

For the salts you should simply brush these off with a dry brush (any form of wet removal will simply dissolve the salts again). For the brickwork if the bricks have severely deteriorated you might need to replace the bricks but for the time being I suggest you simply keep the problem under observation.

This advice is of course given from a distance without having seen the property. Your problem is fairly typical of dampness getting into the base of a chimney but there are a number of possible reasons and therefore a number of possible solutions. You should seek advice from a professional experienced in dealing with buildings of this nature.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: What mortar should I use to rebuild flint wall?
FROM: Paul Buchanan (Canterbury, Kent)
I want to rebuild a flint wall with local flint (which is in abundance in the garden) - what mortar do I use and do I have to treat the flints in anything special?

Paul Buchanan

Traditionally flint walls were constructed in a lime mortar. As flints are quite hard they can withstand a relatively hard mortar and a strong mix can be used, perhaps even a naturally hydraulic or semi-hydraulic lime. As far as I am aware there is no special preparation necessary for the flint but it should of course be cleaned. The flint should be carefully sorted in such a way that the majority of flint would form a freestanding wall without the mortar. The reason for this is to ensure that the wall, when constructed, is not purely relying upon the mortar to hold it together. As you are based in Kent you might be interested to know that in Essex the County Council run courses at Cressing Temple (near Braintree) and each year one of them looks at the use of flint in building. If you would be interested in going on such a course you should contact Pauline Hudspith at Essex County Council Historic Buildings Department (Email:

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: Re-pointing a 3-storey farm house
FROM: Lynne Larkman (Bampton, Oxfordshire)
We own a very tall 3-storey stone farm house which badly requires the west wall re-pointing. We have found a very good scaffolding company and now need to find a reliable builder to do the job. We have seen how difficult this can be to get right on properties in the area and understand that a hard mixture is as bad as one that is too soft. How do we know that the said builder has got it right? I would much prefer an elderly qualified brickie but couldn't send one up so high especially as the said wall has a lower attached cottage with its roof adjoining, hence the need for very complicated scaffolding. Is there also a way to prevent sparrows from picking out the pointing from between the stonework? We have seen them doing this on the single storey stable walls!

Lynne Larkman

You do not say how old your building is and precisely what type of brick or stone it is constructed from. However, as a rule of thumb the pointing should always be softer than the brickwork/stonework as it is the pointing that should be sacrificial and therefore wear and deteriorate before the brickwork/stonework. In any event, it is easier and cheaper to re-point than to have to replace bricks. I would go further and suggest that a hard mortar is more of a problem than a mortar that is too soft. At least a mortar that is too soft can be raked out and re-pointed and it does not cause any major problems for the brickwork/stonework. A mortar that is too hard is difficult to remove without causing damage and will inevitably lead to problems for the brickwork/stonework. It is important that you use a lime mortar. The precise mix will depend upon a number of factors, as will whether you use lime putty or hydraulic/semi-hydraulic lime. The time of year the work is undertaken, the nature of the brickwork/stonework, etc are factors that will influence the choice of mortar, as will the exposure to weathering. It is not possible to advise on the precise mortar to use in this instance without seeing the property and its situation. Further guidance can be obtained on mortars from the websites of Michael Wye & Associates or The Old House Store (see the Building Conservation Directory). These are not only suppliers of the materials but information on mortars etc is posted on the websites.

The problem of sparrows picking out the pointing is not something I have had to deal with in the past. I suspect that they are gaining some nutrition from the calcium in the lime. It may be that others have an answer to this.

Period Property UK would like to thank Stephen Boniface Associates for answering this question. Stephen Boniface can be contacted on 01279 421 500


SUBJECT: How do I finish flagstones to halt dust and highlight their colour?
Robert Quail (Benfleet, Preston),
Matthew Hayes (Newport, Gwent),
Keith Munro (Chelvey, Somerset),
Patrick Sorrell (Theydon Bois, Essex),

Angela Riddle (Somerset)

Firstly, and most importantly, you should not use a modern sealer on flagstones. The use of such a synthetic material alters the appearance and colour of the flagtones, as well as inhibiting the ability of the floor to breathe if they are laid directly on to earth or chalk without a dpc.

On the finish front, one part linseed oil and 4 parts white spirit will help to highlight the colour of the flagstones. Beeswax can then be sparingly used to give the floor further protection and a slight sheen. SPAB have an excellent leaflet on the caring for and finishing of stone and wooden floor which I recommend you all purchase for a few pounds and read. They can be contacted on 020 7377 1644.