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 (

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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...


SUBJECT: Lender does not like single-skin walls.
FROM: Lorna Hunt (Essex)
We are thinking of buying a 2 bed semi-detached in Braintree which was built in 1881 and has a single skin wall to the rear of the property (bathroom and kitchen). The problem is that the Nationwide who were destined to be our mortgage provider will not lend on this type of construction.

Our question therefore is twofold:

What is the process involved with upgrading a single skin wall, and roughly how much might this cost? and/or

Are there any mortgage lenders out there who will lend against this type of construction?

We are first time buyers and don't have the capital available to do the work initially, but hopefully would be able to over time and the vendors have reduced the price to compensate for the defect.

Also the property has an asbestos flue to the current boiler and we are planning to rip out the old boiler and install a new boiler and complete central heating system. Would you know how much it might cost to have the asbestos flue removed?

Lorna Hunt

This is a very similar situation to those where a building has an extension built of single skin brickwork. A question on such extensions was posed recently and answered on this site. I suggest you look at that answer because a similar reply applies here.

Yes there are mortgage companies who will lend. Search the Discussion Forum and you will find names of mortgage companies suggested by other home owners.

Remember that a mortgage company will usually be guided by their valuer and often it is not a matter of 'policy' but the advice given by the valuer.

A single skin wall can be upgraded in a number of ways. The first thing to establish is that the wall is sound (no cracks or movement, etc.). It will normally be taking all the loads from the roof, floors, etc., but this is not greatly different from a modern cavity wall where only one skin of the cavity wall will usually bear loads.

The main issues with single skins are water penetration, condensation, heat loss, etc. The easiest way to upgrade is to provide an external cladding. However, external cladding is the most obvious alteration, affects the appearance, affects the depths of reveals at windows and doors and if the property is terraced it creates a problem of wall depth at the boundary with the neighbouring properties.

The other methods are various internal linings, false internal walls, etc. These have again been discussed on the Discussion Forum where you should find quite a lot of very useful advice from others who have faced this problem.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.



SUBJECT: Does my clay lump house need stripping of modern materials.
FROM: Mark Cheeseman (Norfolk)
I have recently moved into a Clay Lump cottage which has concrete render externally, vinyl paint internally and also an injected DPC on two walls. Having read the article 'Earth Buildings and their Repair' by Dirk Bouwens this looks like a disaster waiting to happen. Presumably it will be relatively straightforward to replace the concrete render with 'Limetec feebly hydraulic mortar'? But can the vinyl emulsion be removed ? and what about the injected DPC, have the chemicals used caused irreparable damage?

Mark Cheeseman

Yes, it is a disaster waiting to happen. You must be very careful, but must tackle the problem.

Do not strip all of the render at once, as it could be the only thing holding the building together. Undertake some very careful localised opening up to establish what the general condition of the wall structure is like. It is possible that you will have to insert temporary props, shuttering, bracing, shores, etc. to prevent collapse during the work.

You must take off the render completely over time and perhaps in sections (to avoid collapse). The wall will need consolidating if it has deteriorated (it probably has) and earth blocks will need to be made up to use for the repairs. Once repaired re-render should take place using Fat Lime (Lime Putty) as this is the most appropriate for this type of building. Feebly hydraulic lime is a second best option. Speak to suppliers such as Mike Wye and The Old House Store.

Internally you should remove impermeable materials as breathability is almost as important for the internal surface as for the external. You may have to remove modern plasters, etc. as well. Repair the wall structure and plaster with lime plaster and finish with limewash.

The injected DPC is irreversible. If inserted in a brick plinth below the earth structure I doubt it will be a problem and is not something you need be concerned about.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.


SUBJECT: How do I repair eroded stone on terraced property.
FROM: Howard Lawes (Somerset)
I want to repair the stonework around my Victorian Bath stone terrace. In places the stone has eroded. I have been told that I can fill it out using a mix of lime mortar and bath stone dust. Is this the case, and if so, what proportions should I use for the mix?

Robert Bottle

Is the erosion really bad enough to warrant major work? If so, speak to a local stone mason about piecing in matching stone.

A lime render patch repair is a possibility and a lime putty with bath stone dust mix could be used, but I question the wisdom of such a repair. If the erosion is on corners, a patch with lime render is likely to fail relatively quickly. However, the best method of repairing stone is to cut back and piece in new pieces of matching stone.


Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.



SUBJECT: Conservation says its a limeash floor, builders claim its cement. Whose right?
FROM: Mandy McMahon (Staffordshire)

We have recently bought a Grade II listed farmhouse. Our conservation officer has visited, and indicated that the floor in two bedrooms at one end of the house are lime based and must be kept. Is this correct, the beams underneath which form the kitchen ceiling are bowing and causing concern. Local builders have inspected the floor and say it is cement, in which case, can we remove it?

Mandy McMahon

In your part of the country it is quite possibly a lime ash floor. Builders inexperienced in historic buildings often mistake this type of floor for cement. I suspect the conservation officer is correct.

SPAB produce a useful leaflet on lime ash floors. The SPAB technical officers can provide more advice on this type of floor and details of contacts for builders who can assist and repair or strengthen such a floor appropriately.

Remember that just because a floor is sagging does not mean there is anything wrong. It could have been like that for many years and provided it is not overloaded it will probably survive for many years to come.

If you follow your builder's advice and are wrong you could face criminal prosecution. You would be very foolish to ignore or disregard the conservation officer.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.



SUBJECT: Next door neighbour's wall has damaged my bread oven.
FROM: Name withheld
I am restoring the 16th century cottage that has been in my family for 150 years . During the project I opened up the fireplace that had been bricked up by my Grandfather in 1965 to reveal the impressive inglenook. Upon inspection, I found that the bread oven, originally intact and undamaged had been cut through by a wall built in 1976 by the homeowner to the rear of the property. It had also been reduced in size by a third! What remains of the oven and the many tons of stonework in the chimney above has been left supported by just three stacks of regular bricks just placed one upon the other, one stack having no mortar at all! The foundation of this wall extends well into our property by at least 750mm W 300mm H and 1.25m in length.

I discovered that permission had been granted by my Grandfather to the owner at the time (1976) allowing him to build an extension that would butt up against the rear wall of the house. It did not give permission to go beyond and through the wall, annex property, destroy a bread oven and leave it in such a dangerous condition. As the fireplace was bricked up at the time this work took place it went unnoticed until I opened it. What are my options in this situation? is this covered by the party wall act?

Name Withheld

The Party Wall Act did not exist at the time of the work and does not help you now until or unless work is undertaken to the party wall to remedy the problem.

There are several issues here and I suggest you firstly seek legal advice. If you look at your house contents insurance you may find you have cover for legal costs in a dispute and this may help fund legal advice.

The first problem is the trespass. You will need to carefully check the permission given by your grandfather and ensure that there is no risk of misinterpreting the permission. If it is clear that the permission did not include for intruding into the bread oven/chimney base you may have grounds to request the trespass be removed. However, there is the matter of length of time, although as it is only now that you could reasonably have discovered the trespass and you may still have a right to take action despite the passage of years. This is what you need legal advice about.

The next problem is the technical issue of support for the chimney. Your neighbour (or predecessor) has caused a structural weakness and now that this has been discovered it needs to be rectified regardless of the matter of the trespass. Again you need legal advice on what action can be taken to rectify the technical problem.

It is when you have answers to the above issues that you will need to undertake some form of building work and at that point the Party Wall Act will probably apply.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.



SUBJECT: Does my roof really need a lining if it's leak free?
FROM: Colin Doyle (Cheshire)
We are selling our house and the surveyor has said that not having a roof liner is a problem. The house is 100 years old, has no leaks so I am a little confused.

Am I mistaken or as long as the existing roofing system is maintained i.e. tiles are maintained and replaced if needed is this not just a Surveyor trying to find a problem i.e. the roof system designed 100 years ago works perfectly if maintained properly.

Colin Doyle

The lack of a lining is not a problem. Surveyors will routinely point out the lack of a lining, but lack of a lining is not a defect.

If a roof is leaking it will be due to a problem on the face of the roof (the tiles, ridges, etc.) and these external areas will need attention. The lining should not be the primary protection against leaks and should not be regarded as such by a surveyor.

Modern regulations do require a lining if a roof is being re-covered. However, there is nothing to say that an older unlined roof has to have a lining.

Prior to the 1920s/1930s no roof was lined. However, when lining materials (building papers and then roofing felts) were manufactured the use of a lining during roofing works made the roofing easier and quicker. Linings were therefore used for convenience. It was also realised that linings can reduce draughts, wind driven rain and snow, etc. and could be advantageous. Further, with the advent of interlocking tiles a lining was more important because if a tile failed there was nothing between it and the roof space below (unlike traditional overlapping tiles/slates).

I would always argue that a lining is perhaps more important with interlocking roof coverings where there is only one layer of the covering over any part than with overlapping coverings where the failure of one unit rarely leads directly to a leak.

In recent times the disadvantage of linings has been seen with an increase in roof condensation problems, hence the advent of breathable linings.

An existing roof with a covering in sound condition has no need for a lining to the roof and it is unwise to try to line from the interior (a lining should be over the tops of rafters not under them).

In your instance find out what the surveyor really said. It could be that the surveyor did not raise an issue with the lack of lining. Is your purchaser making something out of nothing for negotiating purposes?

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.


SUBJECT: How do I deal with Death Watch Beetle?
FROM: Alex Hardy (Surrey)
We are in the process of buying an 17th Century Thatched cottage in Berkshire. The surveyor picked up the fact that it has an infestation of death watch beetle but did not know if it was active or not. I do not want to use chemical treatments as the opinion on these seems to be that they are largely ineffective. I understand that the beetle dies if the humidity in the timber drops to below 12%, as a solution how practical is this, especially in roof timbers? is it a question of buying a dehumidifier or will the building dry out if it's used and the sources of damp eradicated (there is rising damp as a concrete floor has been put down which is forcing water up the walls which we are going to rectify by ripping the concrete out and installing a sprung wooden floor.)

Alex Hardy

Even if the beetle infestation is active surface chemical treatment is unlikely to kill it. Rather it could kill the beetle's main predators and the beetle infestation could increase.

The issue of Death Watch Beetle is too extensive for a brief answer here. If you have got an active Death Watch Beetle problem in old timbers it is almost certainly because the timber is damp. You therefore probably have a damp problem somewhere and this needs to be investigated and dealt with.

However, it is often the case that more damage can be caused trying to find and kill off Death Watch Beetle than the beetle will cause if left alone.

You must first establish whether there is an active problem and then find out how extensive it is to decide whether you really need to do anything about it. I suggest you seek independent advice from someone who understands these matters and has no vested interest in selling you a 'treatment'.

I therefore generally agree that dealing with dampness generally and allowing the building to dry out should resolve any problems over time. I doubt that dehumidifiers will be necessary. However, you may have to accept that the DWB will continue for some years before it dies out naturally. If it is limited in numbers I doubt it will cause too much damage, but you really ought to get independent advice from someone who can come and look at the problem.

I am glad to see that you are prepared to rip out the concrete floor.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.


SUBJECT: How do I improve insulation and rid myself of damp in my listed property?
FROM: Sally Mellor (Lincolnshire)
We have a Grade II listed building and the insulation issue is a major concern. A new product called Sempatap has been suggested by the local council energy office but I don't know if this could cause problems. The other alternative is called Wallstransform. Have you had any experience of either of these products. I don't want to invest and find they make matters worse or no better. The walls are stone with a rubble filled cavity and damp is also a consideration. Do you have any experience of Electro Osmotic damp treatment.

Sally Mellor

I am sorry but you really have not given sufficient information to provide a detailed answer.

You do not say why insulation is a major concern. Historic buildings can be insulated in roof voids, draught proofing to windows and doors (secondary glazing is sometimes acceptable), etc., etc. It is possible to insulate an historic building to good levels. Many historic buildings I inspect are often warmer than their modern counterparts. Lime mortar/render is a warmer material than cement/concrete and thick stone walls with lime mortar tend to be fairly good insulators and act as heat stores generally. This may explain why many historic buildings tend to be warmer than modern buildings.

That said there are many opportunities for draughts etc. that could lead to greater heat loss. You really need to find out what the problem is.

It may be that you have a very specific problem, but in that case it would require an inspection by an independent professional to give advice.

If you do have damp walls these will be colder and could explain part of your problem. However, modern treatments are not appropriate for this type of house. They rarely do any good and often cause more harm.

Historic walls function by way of moisture management. If you have a damp problem it is probably due to a build up of ground externally, leaks from rainwater goods, perished pointing, poor maintenance generally, etc., etc. Has a concrete floor been laid because if so this has probably exacerbated the damp problem (displaced ground moisture to the bases of walls)?

I have not used the products you name but looking at the technical specifications they may well provide good insulating properties, but they also create impermeable finishes. If you seal up the walls with impermeable finishes you will increase the likelihood of damp problems. I would not use these products on historic buildings.

The problems should be considered holistically by a professional who properly understands historic buildings and how they function.

Regarding the system of 'damp proofing' you mention, I have never recommended its use in any property and I have not seen a property with it installed where it has resolved the damp problems. In theory it is a system that sounds plausible, but in practice it is not a system I would use.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.


SUBJECT: I want my VAT back!
FROM: Anne Eames (Bedfordshire)
Our house is Grade II listed. We have recently had an extension built in accordance with a planning & heritage application and were charged full rate VAT by the builder. We believe that this should have been zero rated. Furthermore, the relationship between ourselves and our builder deteriorated during the works and we also understand that we cannot claim a VAT refund, if one is due, it can be only be done by the builder. How can we ascertain that the works should be zero rated and is there anyway we can make the claim as a customer if we have a case?

Anne Eames

You should have resolved this in advance of the work.

The builder is the one responsible for the VAT and if the builder does not want the hassle of dealing with Customs and Excise, or has any doubt about VAT exemption there is little you can do about it.

If your relationship with the builder has deteriorated there is probably nothing you can do about this. However, before giving up speak to a VAT specialist. The Listed Property Owners Club has a regular feature on VAT and there is a specialist in the South-West, David Brown of Bishop Fleming who often advises through their magazine and web site (you have to be a member to get information from the site). Mr Brown can be reached through

VAT exemption is a specific and specialist field of work. The above are pointers only. There have been discussions on the Discussion Forum pages of this site where others have shared their experiences of getting VAT exemption. You may find their comments helpful.

If your dispute with your builder deteriorates to the extent of a legal dispute you could possibly include the VAT issue as an item of recovery, or at least an item to show the lack of knowledge, incompetence, etc., etc. of the builder.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.


SUBJECT: Hey, you've stolen my chimney!
FROM: PoppyPatch (Midlands)
I live in a 350+ year old thatched stone cottage which is a Grade 2 listed building. My property and that of my next door neighbour were originally one property which at some point was divided into two small cottages(I don't know when) When I moved into the property 4 years ago there was a wood burner stove in the fireplace attached to a liner in the chimney which we understood was a shared chimney. The liner was installed about 27 years ago. Our neighbour has recently uncovered his fireplace, discovered that smoke filtered into our house and then claimed the chimney as his property and had our liner removed. He gave us 7 days notice that she intended to do this. Our solicitor has been in contact with his solicitor but he does not respond and is going ahead with plans to block our access to the chimney which is large enough to accommodate several liners. Is he legally able to do this please?


As you have a solicitor involved this is something you should ask the solicitor.

My view, based on this limited information, is that she cannot do this. Further, I suggest that any work to the chimney interior is a Party Wall matter under the Party Wall Act. Blocking up a shared chimney is notifiable under the Act and if she fails to notify warn her she could face a court injunction.

Implementation of the Act should at least force her to consider all the options.

She may well have genuine concerns however, in view of the recent spate of thatch fires caused by wood burning stoves. Such a stove burns at a high temperature and has to have a liner (double skin). However, such liners have a limited life (usually about 20 years) and yours could well be at the end of its life.

A suitable solution may be to offer to have the chimney re-lined and insulated in a way that minimises the risk of fire, rather than simply blocking it off.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at the The Whitworth Co-Partnership with Boniface Associates for responding to this question.