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: Does a clunch property really require an injected dpc?
FROM: Nick Lloyd (Surrey)
My wife and I recently purchased a 17c Cottage, the original building being made from Clunch (chalk Block). A structural survey indicated the presence of damp in the original section of the building & advised chemical dpc as a solution. This is the only section of the building found to be damp. Our mortgage providers agreed and introduced a retention on the monies until the dpc had been installed. A local company then injected into the chalk 2 inches above floor height on my instruction and advised we remove all internal plaster to a height of 1 mtr renewing with moisture resistant concrete render. (incomplete). Subsequently I found your site on the net tonight and was very distressed upon reading your comments on chemical dpc in "Earth" walls. Please can you advise me on the appropriate action I should take?

Nick Lloyd

Unfortunately, chemically injected dpcs cannot be removed. What might happen in future is that the section below the dpc will become saturated, assuming the dpc does its job and prevents moisture naturally rising any higher than the injected dpc. What might then happen over time would be a gradual deterioration of the material below the dpc. I have often seen brickwork deteriorate in this way, below an injected dpc. To alleviate the problem you could create an open trench externally to expose more of the wall face below the injected dpc level. This would enable moisture to evaporate and escape before it reaches the injected dpc and might help reduce the risk of saturation, etc.

The internal wall surface is slightly different in that the render/plaster can be hacked off. I suggest you do this and replace it with a traditional lime plaster that will allow the wall to breathe. You may find that the low area between floor and injected dpc will remain damp and show as a stain, with occasional need for re-plastering. However, you could leave this area clear of plaster and disguise it with a deep skirting carefully fixed with non-ferrous fixings above the injected dpc, leaving a slight gap between the floor and bottom edge of skirting. Make sure the rear face of the skirting is primed - to give some protection from the moisture.

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: Improve ventilation & provide more even heating to avoid condensation.
FROM: Nigel Smith (Shropshire)
I have a 1860 built solid wall house, it has had a damp course, but in the winter we get mould on the walls which is worse up stairs. I have been thinking about installing an air recovery system in the loft, the manufacturers claim this will sought the mould problem, but I don't want to pay for this to find it doesn't cure the problem, the other thought was a de-humidifier but would that work through out the house as we have a problem in the lounge bedrooms & kitchen.

Nigel Smith

I confess that I don't know much about air recovery systems. However, what you describe seems typical of a condensation problem. Condensation is best tackled by considering heat, insulation and ventilation. Sometimes it is not possible to do anything about insulation, especially of walls, but changes to heating and ventilation are often possible. What you need to try to achieve is a more consistent level of warmth throughout the building over the course of each and every day, together with improved air changes (ventilation) so that moist air is taken away naturally. There are ways of achieving this by simple methods (opening windows, etc), but sometimes extractor fans have to be introduced (best in places where moisture is created - bathrooms and kitchens). In the space of this brief answer I cannot give more detailed guidance. Read other answers and the discussion forum pages for more information.

Bear in mind that for some of the works you may need listed building consent if your building is listed.

If you find that these simple solutions do not cure your problem you could look further into air recovery systems. A dehumidifier will help remove the moisture for now but is rarely a permanent solution. However, in severe cases a fixed dehumidifier with permanent extract duct to the exterior can help, but is a last resort in my opinion.

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: Limewater can help solve dust problem
FROM: Fiona Baldwin (Norwich)
Can you use PVA to seal lime and cobble brick internal walls, in order to prevent dust debris and bring out the colour of the cobble?

Fiona Baldwin

No I would not seal them in this way as the PVA will create an impermeable barrier. This might not be such a problem with the cobbles, but could cause problems with the pointing and brickwork in the long term. If the pointing is crumbling it might be time to consider some careful re-pointing with lime mortar. You could consider using lime water (very thin lime wash) over the surfaces as a general sealant, but this might form a slightly misty surface, which would not matter on the pointing but might show on the cobbles and brickwork. A gentle wash down occasionally might be sufficient to hold back the dust?


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 clean our church windows?
FROM: Gary Thorn (Nottinghamshire)

I've contacted a contractor to clean our church windows using a new pole system & low pressure wash. He assures me it will not do any harm to our very old stained windows, would that be a correct answer? Also is there any reason why it shouldn't be used?

Gary Thorn

I would NEVER use a washing system on a stained glass window. They are just too vulnerable and valuable, and permanent damage can be done very easily. Damp sponges and dry cloths are all that is required, or sponges if the glass is very fragile. Consult a stained glass specialist, or look up Painted glass is particularly vulnerable and should perhaps never be washed. Any water used should be de-ionised anyway to avoid deposition of calcium on the glass surface.


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: Lining chimney costs.
FROM: Jane Morton (Tyne and Wear)

We have a first floor flat in a Georgian house and would like to use the gas/coal effect fire in our living room. We had the chimney swept but were told that it needed relining. To get the metal lining in, some bricks will have to be knocked out of the fireplace then replaced after the lining has been fitted. We have been quoted a price of 2,500. The drop from the top to bottom of the chimney is l7 metres. I've said we will go ahead but am now worried in case I should have sought more estimates. Could you advise me?

Jane Morton

The work you describe is not unusual, when fitting a flue liner. I always advise getting more than one quote, but as I do not have detailed knowledge of costs in Glasgow I cannot comment on he figure you mention. It does not seem unreasonable to me however.


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: Rampant Squirrels become new housemates.
FROM: Lynne Vitale (Bristol)
I am sitting here 9am and all I can here is the squirrel/squirrels in my loft!! I cannot find how they are getting in but the are scratching and moving all over my cottage which has two loft areas-so they are going where they please. This is my first property so I really don't have much idea how to deal with all these 'new to me' old house problems! Is there a way to encourage them to leave? They must be using the stone garden walls to gain access to the roof. Also when I lifted the loft hatch it had rubble on it which appears to be coming from a newly made hole! They are active during the night to. It sounds like they are sporting hobnail boots! Also the condensation and damp is affecting not only the walls but objects such as wooden bowls etc, would an air vent or two help?

Lynne Vitale

Squirrels are rodents and unless protected (red squirrels) they can be dealt with as a rodent by a pest control company. I suggest you therefore seek advice on extermination.

The other problem of condensation that you mention is not dissimilar to the problem raised above and my earlier reply therefore applies here - in general terms.

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: Mining mice make result in rapid degradation of thatch.
FROM: Ann Caswell (Cambridgeshire)
I have a detached thatched property and am not sure if I should insulate the ceiling or not. Currently the ceiling is covered in reed from the thatch which we propose to clear out as we have an infestation of mice on a regular basis. Once we have cleared all the reed we would like to insulate but are concerned about air circulation and the effect on the thatch.

Ann Caswell

The thatch will provide a level of insulation, but without knowing its thickness, etc I cannot say whether it is sufficient on its own. To get to modern levels of insulation you will probably have to add a layer of insulation over the ceiling. However, if there is an impermeable lining under the thatch I suggest you carefully cut this away to give the roof space and thatch itself the ventilation it requires. From what you describe I doubt the roof slopes are lined, but I mention this just in case. The infestation is another extermination issue, by a pest control company. However, if the thatch is netted you will need to undertake prolonged and determined efforts to ensure that all rodents living in the thatch are dealt with. You do not say how old the thatch is. I would be slightly concerned that the infestation has caused damage to the thatch. This might not show at present, but as the thatch naturally wears back the runs created by rodents will become exposed on the surface and lead to speedier degradation, etc. If the thatch is quite new this might not be a problem for some years.


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: Noisy neighbour pushes homeowner to brink.
FROM: Andrew Finlay
I am after some advice regarding my new maisonette that I have just moved into. It is a converted detached Victorian house (1840s I think) and I live on one side of the house on three floors but have a basement flat underneath. I have had it upto my ears with the noise level from the basement flat directly underneath my lounge. I hear her music through the wooden floorboards every night and also I can actually hear her conversation when she is on the phone or when she has guests round. I can even hear her through 2 floors when I am in my bedroom on the 1st floor.

It is without question that I will have to have this seen to, as I can't live like this. I need advice on lifting all the floorboards and having insulation put in. But there is only about 3-4 cm between the floorbaords and the concrete below. So if that doesn't work I may have to get the whole ground floor underlaid and then carpeted at much expense I am sure. I found out the other day that there was a fire in the basement flat last year and that the entire flat was gutted. Smoke came through the floorboards and I wonder if that may have damaged the previous sound proofing?

Do I have a case for suing the vendor for not informing me of the noisy neighbour and fire? Also, please tell what the best thing for me to do is regarding stopping the noise as soon as possible.

Andrew Finlay

On the legal matter of suing the vendor, you should speak to your solicitor about the issue of non-disclosure - if indeed that is the issue.

Noise is a problem that is increasingly brought into the pubic eye and is said to be one of the main nuisances between neighbours. Have you tried talking to the neighbour politely asking them to turn down music, etc. This may not resolve the problem, but might reduce the problem, as it will make them aware if nothing else. Bear in mind that if you hear them they can probably hear you!

Whether the fire caused damage to sound-proofing depends on what damage the fire actually caused and what sound-proofing existed anyway. If there was an insurance claim and it was properly dealt with any sound-proofing should have been reinstated.

I suspect that you are simply in a situation that many find themselves. The property was converted some years ago, before the regulations about sound-proofing, etc. It may be that you must face the fact that to resolve this problem you will need to pay for improvements.

You mention that there is concrete below the floorboards, but it is not clear whether the concrete is therefore the structure (and boards laid over it) or something else. I suspect the concrete is the main structural component and insulation is probably best laid between this and the boards. More importantly, there should be an acoustic isolating layer between the concrete and any battens/joists resting on it, or between the battens/joists and the boards themselves.

I would always advise underlay and carpeting in a flat and many leases now forbid exposed boards for the very reason of reducing the risk of noise problems. Finally, bear in mind that not all of the noise will be through the floor. Noise may be getting up through voids (services), through partitions, windows, etc, etc. Dealing with the floor may cut out much of the noise, but is unlikely to eliminate all of it.


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: Do I need to render exposed chimney brickwork in loft.
FROM: Kevin Rich (Surrey)
We are trying to re-use two fireplaces in our house as proper fires. As a part of this process we have been told that we have to have our chimneys fire rendered in the loft as there is exposed brickwork. The question is what is fire rendering and is it necessary?

Kevin Rich

Have tests revealed that flue gases are escaping through the brick joints. This is quite common because over the years the pointing will have deteriorated and there could be gaps. However, the solution may be as simple as re-pointing the exposed brickwork in the roof space. The issue that has to be considered is whether the flue/s leak and if so whether re-pointing or complete re-rendering are necessary. With regards to the nature of the mortar used for pointing or rendering, it should be of a type that will resist sulphate attack. Traditional lime mortar is probably most appropriate.


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: Never accept conclusions of a free damp surveys
FROM: Jackie Pedley (Shropshire)
We have a 1938 semi. There are tide marks around 3" above the skirtings in places, this is on the external and internal walls, there are quite high damp readings on the meter. When, and if I have a dpc, if the plaster contamination is only 3" high, would I really have to have the plaster removed a meter high?

Jackie Pedley

As you will have seen from other replies and on the discussion forum, the first thing to do is to have the problem properly diagnosed in the first instance, not simply by a company with a vested interest in finding work. For this you should expect to pay for the inspection and advice.

As for whether the plaster needs to be removed up to a metre, in my opinion the answer is no. The reason most of these companies specify 1m is to safeguard themselves. Generally, the contaminated plaster and slightly beyond is all that needs to be removed. This is as much for aesthetic reasons as for anything else.

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: Avoid spraying underside of slate roof with foam
FROM: Martin Consterdine (Shropshire)
I have recently purchased an old Victorian/Georgian school and masters house. The roof is covered in welsh slate and is suffering with nail fatigue. The majority of timbers are in good order. I have been advised by local roofers to remove and reuse slates after first putting down good felt and new battens at a cost to me of 18-25k. I have heard of a product called "Eco Polyurethane" which can be supplied to me for DIY use to spray onto the back of the slates," this torching will insulate, stop slipping slates and eradicate water ingress." 3,000 would provide enough to treat whole roof. I am a good DIYer should I remove all the slates, and then fit felt and new battens, or should I use the spray on polyurethane? Do you know anyone that has used it? Or is it too good to be true ? Whichever way, I will have to do it myself, as I cannot afford 18- 25k on the roof.

Martin Consterdine

I do not recommend using the spray-on foam. If the nail fixings are rusting, the foam does not prevent this deterioration and in fact could accelerate it. When you then have to repair the roof the foam prohibits re-use of the slate. I have often been asked about such products for the underside of roof slopes and I have yet to come across any significant long or medium term advantage. My advice is to have the roof carefully stripped and salvage what you can of the slate (I would normally assume 75% salvage). Replacement slate should be of the same dimensions and colour as the original. When re-laying slate use a breathable lining (I prefer none at all), new pre-treated battens and non-ferrous fixings (but not stainless steel - as they prohibit individual slate replacement during future maintenance). Use Code 4 (minimum) lead flashings and/or lime mortar fillets over Code 4 lead soakers over perimeters and set ridge tiles in lime mortar.

If you are to do this yourself (unwise in my opinion), you could tackle a slope at a time or even vertical tranches, provided exposed sections are immediately lined to give temporary protection. If you are to omit the lining remove it as you slate over.

If money is an issue have you not considered undertaking repairs yourself, as you are keen on DIY? If the problem is nail sickness it means the fixings are rusting and failing over time. They will not all fail together. You could pick areas that are particularly bad and repair those. In such circumstances you will need some lead to make your own tingles. These are strips of lead (c.25mm wide) fixed to a batten then laid under the centre line of the slate, the slate is laid and the lead then folded up to clip it in place along the bottom edge. You can now buy proprietary tingles, but lead is probably better especially for DIY. If you can fix the slate properly you should do so, tingles are only if you cannot get a good fixing direct to a batten. Of course the other alternative is to ask the roofer to do only sections at a time. Have you sought alternative quotes?

Bear in mind that even if doing this yourself you have to comply with health and safety, hence you will need scaffold, etc (do not do this work from a ladder). If you overhang other land have you got third party insurance, public liability, etc in case you drop something on someone's head?

I hope this has given you enough food for thought. Nonetheless, regardless of the difficulties I have identified with DIY or the cost of professional roofing, I do not recommend the use of the spray on foam because it is a short term quick fix that then prohibits any future use of the slate and therefore increases the medium to long term cost of work.

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: Dry lining wall provides solution to penetrative damp.
FROM: Anne Brookes (Gloucestershire)
Some 5 years ago one outside wall in my kitchen was 'tanked' using I believe, Thoroseal. About two years ago the plaster and render began to fall off! I was told when it was done that this method is suitable for underground, and this wall is above ground, yet this happened. The wall had shown signs of damp in patches high on the wall, and so was thought to be penetrating damp. The tanking was undertaken when re-pointing did not solve the problem. I am now in the position where I have to remedy the situation, and have been advised to fit a membrane system. Not only is this very expensive, I also feel it is 'overkill'. Can you give any advice as to a cheaper method. I thought of some sort of drylining perhaps, just to separate the damp wall from the internal finish. Is there a cheaper way to achieve this than the membrane system. Also what is so special about this membrane to make it so expensive - would not any other waterproof barrier that left an air gap work just as well?

P.S. My home is a Victorian terrace - and wall is solid.

Anne Brookes

The standard forms of tanking with 'waterproof' renders generally last 10-15 years before they begin to fail - in my experience. Did you not have a guarantee and even so, what did their literature claim? Surely you have some come-back as 5 years is too soon for failure. As mentioned in other answers, any damp problem should be carefully assessed and this often means a holistic view being taken. You mention re-pointing, but do not say whether this was cement or lime based. If the former, you could still have a problem with moisture trapped in the wall. It sounds like you need a thorough independent assessment. If the decision is that this wall will always be vulnerable (and such problems do arise) and that some form of tanking or internal dry-lining is the only solution it is possible to dry-line in a more traditional way than using the proprietary systems. The reason these systems are now so popular is that they take up less depth (do not reduce the room size so much) and it is usually easier to apply a finish. However, the traditional method would involve using pre-treated battens fixed with water-proof plugs and non-ferrous fixings to the wall, perhaps with strips of an isolating membrane between the timber and wall. Onto this plasterboard or EML (copper or stainless steel) can be attached and then plastered in the normal manner (lime plaster could be used on EML). Leave an air gap at the base (disguise with skirting if necessary). If possible leave a gap at the top into the ceiling void above (disguise/cover with coving/cornice). Be aware that future fixings to the wall have to allow for the nature of the lining and may need waterproof plugs if they are through to the wall behind. Having said all this there is of course a risk that even the treated battens will rot over time, if the wall is continuously damp - which is why the modern systems are becoming popular.

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.