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: Can chemicals from treating death watch beetle damage our health
FROM: Wendy De Verteuil (Rutland)
We have been told by the landlord of our Georgian building that we have to leave whilst he treats the building for death-watch beetle. We have not seen or heard any evidence of this mystery beetle but would like to know whether we really need to move out and for how long? Are all 'non alternative' treatments dangerous to our health?

Wendy De Verteuil

I suspect that the treatment being undertaken by your landlord will be a waste of money and effort. Surface treatment to the visible timbers is unlikely to deal with an active Deathwatch beetle infestation. Deathwatch beetle is more difficult to eradicate and if the source of moisture that sustains the environment enjoyed by the Deathwatch beetles is not dealt with then no amount of treatment will deal with the infestation. Provided the treatment does not cause physical damage to the timbers then I would hope that the treatment is merely a waste of the landlord's money and it will be for landlord to decide what to do. Your concern is more with regard to the effect on your health. The treatment industry will suggest that the chemicals used are safe but in recent years a number of so-called safe chemicals have eventually been banned. What is today regarded as safe may tomorrow be banned. My view is that you should not remain in the property during or for a period after the treatment. I suggest that you should stay out of the property for at least one week after the treatment and the building should be well ventilated during that period. This does of course assume that the treatment is going to be widespread throughout the property. If the treatment is to be more targeted then it could be more effective and less potentially harmful.

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


SUBJECT: Do our external exposed beams need to be treated
FROM: Dawn Long (Upton upon Severn, Worcestershire)
We own a Grade II listed Farmhouse with black painted external beams. We would like to strip them back to the wood and then treat them before leaving them a natural colour. Do we need permission and once stripped how do we preserve and protect them against the elements?

Dawn Long

The question of whether you need permission depends upon whether the appearance of the building in terms of coloured paint, etc is regarded as part of the character of the building and therefore changing this will alter the character. If Conservation Officer believes that it does alter the character you will need to get consent. I suggest you speak to the local conservation officer in the first instance. In many areas stripping paint from external beams would be regarded as a positive move and may not require consent. However, if you are in an area up where the tradition is for black beams you may find it more difficult to get permission. How you deal with the beams once stripped depends upon the nature of the wood. I would assume that the frame is Oak, but other timbers could have been used. If the timbers are Oak then quite often they need no protective treatment, although some would say to coat them with linseed oil is beneficial. You do not say how the panels between the beams are finished. An increasingly popular approach is to limewash the panels and continue to limewash over the beams as well. This has been very successfully used in East Anglia and the south-east generally. It has the advantage of ensuring that the junctions between the panels and the beams are filled with limewash, which provides a sympathetic and suitable finish to such junctions. However, you will need to liaise with your Conservation Officer regarding these matters.

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


SUBJECT: Inappropriate materials lead to continued damp
FROM: Chris Burrows (Colchester, Essex)
I own an 1880 red brick cottage with 9-inch walls which at some point in time has been rather nastily rendered with a hard cement mix. I have recently replastered inside one of our rooms as over the years previous owners had built the path over the slate dpc outside and damp had penetrated the room and ruined the plaster.

The problem is that I assumed the plasterer knew about older buildings, and so he used a normal gypsum based plaster for the walls. Beneath the plaster, I applied a pva mix to seal the wall, and again over the finishing coat of plaster.

I have painted the walls with standard Dulux emulsion, and soon after, the dreaded white effervescent salt deposits have begun to appear in a small area of the wall, pealing the paint away.

Do you think I will have to hack off the 'old' plaster to a height of 1m and use a different plaster to treat this, or do you think that over time the salts will clear up? I am not 100% sure whether the slate course has been compromised, but have ensured that the ground level has been rectified. There remain some small cracks in the render, which I am aware could be a source of possible ingress for water, but we were planning on extending the property soon, so the gable wall will become an internal wall.

I realise there are a lot of questions, but would appreciate your help. I am reluctant to call a company to test the wall for damp with meters as I am aware of their inaccuracies at times

Chris Burrows

I suspect that the cottage was built without a physical damp proof course and red brick construction in Essex generally means a relatively soft brick. Without wishing to seem rather harsh, virtually everything done to the building so far is probably inappropriate and incorrect. The building would have functioned for most of its life quite satisfactorily by way of moisture management. The approach taken with modern materials is to attempt to exclude moisture. The two principles are usually incompatible. When applying modern principles to old buildings they generally don't work and the result is that dampness often becomes trapped. I would refer you to other answers on this site and to the discussion forum. However, generally I suggest that you consider lowering ground levels, ensuring any sub-floor voids are well ventilated, removal of all impermeable materials including dense cement renders, Gypsum based plasters, etc. Modern paints should also be removed. Once these works have been undertaken the building should start to dry out. Once it seems to have dried sufficiently you should brush away (with a dry brush) the salt deposits that may have accumulated. Any repointing or other such finishing works externally should be undertaken with a lime mortar and this includes all renders. Rather than modern masonry paint a limewash could be used if you need to paint the brickwork externally. Internally traditional lime plasters should be used together with lime-wash or perhaps an appropriate distemper. At present I would strongly recommend leaving the damp-proof course and simply ensuring that the ground level is at least 150 mm below it. As a short-term measure you could simply fill cracks in the render to prevent unnecessary water ingress but in the longer term removal of the dense render and replacing it with a traditional lime render is recommended. Of course, if an external wall is to become an internal wall there may be no need for undertaking any particular work. Nevertheless, the principle of breathability should be adhered to.

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


SUBJECT: Does my friend really need to have her thatched roof sprayed in a fire retardant for it to be insured
FROM: Jo Hewitt (Shoeburyness, Essex)
Do you know of any companies within the Lincolnshire area who would spray my friends thatched roof with fire proofing protection? They have been told by their insurance company that they need to see the certificate for this before they will insure them? But they are having difficulty finding any one that actually does it!

Jo Hewitt

My first suggestion is that your friend to should find an insurance company that understands and specialises in the insurance of thatched buildings. Although some thatched buildings have been sprayed externally and there are some imported materials that can be sprayed on the thatch, there is a question over their effectiveness. I am not convinced about their long-term performance or their effect on the thatch. Perhaps more importantly, if they reduce the natural ventilation through the thatch coat itself it could lead to a more rapid degradation of the thatch. Most thatch fires emanate from heat within the chimneys, sparks from the chimneys or generally chimney problems. Other high risks are the electrics in the roof of the thatched building and soldered capillary joint systems for plumbing in thatch roofs. By ensuring that the chimney is lined and/or at least well pointed, etc reduces the risk of a fire significantly. By having the electrical cable protected in conduit and having it checked regularly reduces another major source of fire. By ensuring that there are compression joints for plumbing (that do not require heat to fix them) will also reduce the risk of fire in a thatched roof. If there is access to the roof voids any loose dusty dry material should be removed from the voids. With an existing thatched roof it can be difficult, if not impossible, to retrospectively fully fireproof the thatch. However, by taking these simple precautions it is possible to significantly reduce the risks. If re-thatching in future involves complete stripping of the thatch there are methods now used for new buildings which involve the creation of a fire barrier over the roof structure, leaving a ventilated void and then thatching over the surface. This separates the thatch from the rest of the building whilst retaining natural ventilation through the thickness of the thatch. This is a very short and potted answer to what is quite a complex problem. However, there are thatch insurance companies that should be able to assist you. In the first instance I suggest that your friend turns to the insurance services provided on this site or contact the Thatched Owners Group Tel 01767 600 707 for further guidance.

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


SUBJECT: Structural problems require specialist advice
FROM: Ian Williams (Boston, Lincolnshire)
I am in the process of trying to purchase a Grade 11 listed vicarage and 2 out buildings. I intend to employ a structural engineer once an agreement of purchase has been agreed in principle with the vendor (Church of England) However there appears in the coach house (A building in excess of 1600 sq. feet) to be a problem with the footings - substantial gaps in one 12 inch wall and advice from various parties to " look into the building very carefully" My question is 2 part - firstly what is the recommended method of repair to faulty footings - I note on one of your answers you mention that underpinning isn't regarded as the only solution.

Secondly can this type of work be carried out by me or do I need to employ a specialist firm.

Ian Williams

The first step should be to have the problem properly and fully assessed. This should be undertaken by a Structural Engineer who properly understands historic buildings and has experience dealing with them in a sympathetic manner. Unfortunately, most engineers are trained to deal with modern buildings. A relatively small number are truly experienced in dealing historic buildings. Of those I am aware of, The Morton Partnership or Cameron Taylor Bedford may be able to assist you but neither of them are particularly local to you. The Society for the Protection of Ancient Buildings may have names of engineers in your area. The engineer would be able to assess why the movement occurred in the first place and whether it is an ongoing problem or something that is historic and can safely be ignored. If it is ongoing and remedial work is necessary the engineer will advise on the most appropriate solution. Underpinning is usually regarded only as a last resort partly due to its cost but also partly due to the fact that it is not always the most appropriate method of dealing with movement. Until the cause is known and the nature of the remedial work established, it is not appropriate to consider whether the work is something you could undertake. Even if underpinning is necessary it is not necessarily the case that a specialist company should be employed. Provided the work is fully specified a competent building contractor should be able to undertake the work satisfactorily. Alternatively, if you have the appropriate building skills you could also undertake the work if it is fully specified and the method explained in detail. However, if a non-specialist builder or you undertake the work there would be no guarantees available that could then be passed on to a future purchaser. The most important thing is to have the work assessed properly by a qualified engineer and for that engineer to then supervise and deal with the general management of the work on site.

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


SUBJECT: Our house is sprouting fungi
FROM: Keith Munro (Chelvey, Somerset)
We have an unusual fungus growing from several cracks where wood meets plaster in our 800-year-old property. The fungus looks like a single, large flat mushroom and is pale orange in colour. We have taken some photographs of these but are unable to attach them. We would be interested to know whether this is inherent in period properties or whether this indicates a potential problem and if so, how it might be treated.

Keith Munro

Your description does not make identification easy, but it does seem likely that the fungus you describe is a wood rotting Fungus. It is possibly dry rot. The fact that it has appeared on the surface suggests a significant problem. You will need to have the area fully exposed to establish the extent of the problem. If a fungus is growing there must be a source of dampness that helps to sustain the growth. The cause of damp must be properly established and dealt with. If the dampness is not dealt with then no matter what other work is undertaken the fungus will probably return in due course. Your problem is in need of quite urgent attention and you need to seek independent advice from a professional experienced in dealing with historic buildings. In your region I would suggest that in the first instance you contact Hartley Conservation (based in Frome) or Philip Hughes (based not far from Wincanton). You should avoid advice from a company with a vested interest in the advice it gives. Present-day thinking suggests that most fungal growths can be dealt with by commonsense and general building works rather than expensive treatments. In any event, one needs to carefully identify the problem and extent of the rot to avoid unnecessary removal of sound timber. Most rots require very specific conditions in which to grow and if the environmental condition in the property is changed to remove the elements required to sustain the outbreak, the fungus should not return. However, it is imperative that you seek professional advice on these matters.

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


SUBJECT: Frost damaged bricks leads to potential problem in dealing with damp
FROM: Alison David (Derbyshire)
We have just bought an old house, the bricks are apparently frost damaged and we have been told that if we have damp proofing pumped into the brick under pressure it will cause more this true? What would you suggest that we do in order to damp proof our house?

Alison David

The information you provide it is insufficient to give any detailed advice. I would need to have more information on the precise nature of the bricks and the specific damage that you refer to. As a general rule, any chemical, liquid, etc pumped into brickwork under pressure could cause damage and could cause faces to fail. It is not necessarily the case that your house needs to be damp-proofed. There are many possible solutions if there is a serious problem of frost damage that involve protective finishes that still allow the building to breathe and function properly. Simply to cover the problem with modern impervious materials could simply result in a more serious long term defect because it traps moisture within the structure. You should seek advice from a professional or a specialist bricklayer or re-pointing expert in your district who can advise properly with regard to the problem affecting the bricks and what is required. Those advising you should be 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