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...


SUBJECT: What should we finish our new oak windows with?
FROM: T. Collinson (Cuckfeild, West Sussex)
We are about to replace out existing windows with oak windows. Danish Oil has been recommended to protect them. Do you agree? If not what would you recommend and if yes does this stop the wood blackening. We have an awful lot of windows so need to minimise annual treatments where possible.

T. Collinson

Whatever treatment you provide to the oak there is almost inevitably going to be some drying out and therefore a degree of slight distortion and splitting. With smaller joinery members (such as in windows) it is likely that a kiln-dried oak has been used and this should reduce the amount of damage through drying out. No form of paint, oil etc will prevent this.

Oak can be left exposed with no treatment and it will survive many years if not centuries. Danish oil is a treatment that could be used but other treatments that might be appropriate or even more successful would be linseed oil or simply beeswax. None of these treatments will stop the wood gradually darkening with age. Oak tends to go a silvery grey. My suggestion is that you use linseed oil occasionally. You will have to accept that the oak will go a silver grey colour in due course. Linseed oil will attract the dirt which will make it go darker more quickly. Danish oil dries to a thin skin and does not go dark as quickly. You could apply a stain, but this might not look so good.

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: Surveyor's verdict on oak roof structure could jeopardise sale
FROM: Ian Bagshawe (Derbyshire)
I am selling my grade II listed Georgian property. The buyer's surveyor is claiming that the original oak purlins have been infested with woodworm and there is insufficient strength left in them to adequately support the roof. I asked a builder with experience in old properties for his opinion. He chipped away at the beams and declared that the woodworm had not been active for a long time, and also that the damage is limited to the outer sapwood only. In his opinion, the heartwood at the centre of the large purlins is as" hard as steel" and it would be both unnecessary and detrimental to the property to replace these with modern purlins. We have passed this information on to the buyer but I think they are unsure about who to believe. What do you suggest?

Ian Bagshawe

Before embarking on a criticism of the surveyor we ought to find out what evidence he/she has seen to suggest that there is a problem. There will be some historic buildings where the remaining dimension of uninfested timber is slender and open to question regarding its integrity.

Your purchaser's surveyor should read the latest edition of the BRE publication on "Recognising Wood Rot and Inspect Damage In Buildings". Your purchaser's surveyor should also be directed to this site and the discussion forum where he will find much on this subject.

You do not say what sort of roof covering you have and you do not mention the dimensions of the original timbers and what the surveyor believes is left. An engineer could attempt to calculate whether there is sufficient strength in the remaining timber (although with old timber the 'calculation' is an inexact science and more a matter of judgement). If the timbers are already inadequate there would be signs of weakening and ongoing failure - does such exist? If this evidence is not present then there may not be an imminent problem. It is true that insect damage can cause timbers to weaken but this is perhaps more of a problem with the less durable hardwoods (such as Elm) or softwood. It is not usually such a problem with oak.

It is far too simplistic for a surveyor to suggest that simply because the sapwood is heavily infested there is automatically a problem with the remaining dimensions of the timber. If this is the surveyor's argument, perhaps the purchaser should seek advice from someone who properly understands the type of building.

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: Island cottage suffers in hands of its former surveyor owner.
FROM: Mike Henley (Nottingham)
Our family has a 200-year-old holiday cottage just above the sea in the Isle of Wight. It is very exposed to the elements. Just before we bought the property 7 years ago the former owner (a surveyor) removed the ground floor boards and filled the whole of the ground floor with concrete. The front of the building has a concrete render and the rest of the building is bare or painted stone.

Since we bough the property a damp problem has become steadily worse, affecting the front (rendered wall) the worst but also to a lesser degree other walls in the property. Basically the internal plaster is lifting off from the stone beneath, usually in a seriously unsightly way. Externally the property has a 1-foot trough of gravel and the ground is lower than the floor. Previous craftsmen have used various impervious materials outside and inside but the problem has become steadily worse. Our most recent advice has been to dry line the walls, can you suggest anything more constructive?

Mike Henley

You mention that the cottage is just above sea level in the Isle of Wight and you suggest that the ground floor has been taken up and replaced with concrete. I suspect that there are high ground water levels in the ground naturally. The insertion of a concrete floor has trapped the moisture under the building and has driven it out to increase the amount of moisture at the bases of walls etc. I suspect that this might be the primary problem with increased dampness around the walls.

You also mention that the building has a concrete render and that parts of the rest of the building have painted stone. Again, these materials prevent the building from drying properly. If it is in an exposed location an impervious finish might help prevent some direct water penetration but where there are cracks and gaps the water will still get in and yet then be unable to escape. With breathable finishes such as lime render and lime wash the moisture will be absorbed by these surfaces and then when it is windy or dry it will dry out again.

My preference would be to have a suspended timber floor with a ventilated void beneath. It may occasionally fill with water but provided it is deep enough the water should not affect the timbers (which should be pre-treated and have an isolating membrane between the timber and any surface likely to become damp). The elevation should be stripped of impervious materials and replaced with traditional lime renders and lime wash. Internally dense modern concrete and plaster should be removed and replaced with traditional material.

The other problem you are probably suffering is severe condensation. Impervious modern materials tend to be colder than traditional materials and if you are in an exposed location you are more prone to condensation particularly on cold surfaces. Reverting to traditional finishes etc should resolve the problem. However, it would be sensible to seek professional advice from someone who properly understands old buildings in the district (not the previous owner). Dampness like this can be a complex problem or as simple to resolve as making sure that there is adequate ventilation.

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: Should my underfloor heating system be incorporated into a concrete floor?
FROM: Jaqy Halstead (Lincolnshire)
My house is 500 years old and built of built of Blue Lias. We're renovating totally, including removing concrete render from the inside and out to allow the house to breathe again. I was thinking about putting in an underfloor heating system. The company has suggested a concrete screed, then a Damp Proof Membrane, then the insulation with the piping, then another concrete screed. However, I'm worried that this will push any moisture up the walls. Is there any other way that I can install this system whilst protecting my house? Radiators will look totally out of place and, in any event, I don't have much wall space as there are so many windows.

Jaqy Halstead

You do not mention what sort of floor exists at present. If there is a suspended timber and boarded floor I suggest that you have the under floor heating incorporated into the existing timber floor rather than changing it to concrete. I have seen these systems successfully installed in timber floors. They may not be quite so efficient and the work may be more costly but I believe it would be a more satisfactory solution in this instance. However, if your floors are already solid construction I would not recommend installing concrete floors as I believe this could pose other problems. The modern under floor heating system should incorporate plastic pipes and should be a double skin pipe or suitably protected from oxygenation. This type of pipe will not be affected by moisture in the floor itself. A traditional breathable floor should be possible. However, on the discussion forum you will find numerous postings about the use of inventive methods of creating modern solid floors but providing appropriate insulation and maintaining breathability. I believe that the company Between Time based in Ware, Hertfordshire has experimented with under floor heating in breathable solid floors. They may be able to provide further advice. It might also be worth investigating electric under floor heating, which is very flexible and controllable.

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: Cracked & spoiled plaster around wood burner flue raises concerns.
FROM: Dave Mortlock (Colchester)
We have installed a wood burner in our recently built lounge. The installer did not have a hole cutter, but simply drilled round the flue and chopped out the relevant block/brick work. Now that the wood burner is operating, the repaired plaster around the flue is continually cracking and breaking, due to the high temperatures. What is the best way to repair the plaster to stop or at least minimise the problem?

Dave Mortlock

Although the installer did not have a hole cutter it is unlikely that this itself is the reason for your problem. The problem is that the surrounding surfaces are in contact with the flue with no isolating insulating barrier. It might now be necessary to carefully dismantle the flue enlarge the hole slightly and then place a suitable insulating material between the flue and the surrounding brick/plaster. Once this has been undertaken the damaged plaster can be removed and re-plastered, using a special fire proof mortar.

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: Wonky oak floor may leads to furniture problem.
FROM: Susan Daltrey (Gillingham, Kent)
We are in the process of purchasing a Grade 11 listed Timber Framed Cottage about 400yrs old in North Essex, like lots of people this is our dream of owning a period cottage with a Thatched Roof. The problem is we don't want to change it too much, but preserve what is there. There are 3 bedrooms with 2 staircases and one room situated in the middle. We need to know if there is away of levelling the bedroom floors? They are uneven to the point that placing any furniture would be a huge problem! The floors are of original Oak timber.

Susan Daltrey

The problem of uneven floor is quite common. Different people have different ways of dealing with this; some are happy to accept the floors and simply put their furniture etc on wooden blocks and I have seen many properties where this works very well. Such work would not require the involvement of the conservation officer etc. The alternatives for levelling the floor would require listed building consent in most instances. There are two main ways of dealing with this. One is to create a false floor above the original leaving the original in place. This is far less damaging and could easily be removed should someone wish to do so to inspect the original floor structure or reinstate the original floor surface. The only slight problem is that it does not give an opportunity to inspect the floor structure now to deal with any hidden repairs, etc. The other method would be to carefully lift the existing boarding, repair and if necessary strengthen the floor and then install levelling pieces and reinstate the old boarding on the levelled floor.

These are your basic options but precisely how you progress will be a matter of liaison between you and the conservation officer. I would of course warn you that in trying to take up the existing floor you could lose some of the original boards as they will fail. I would also warn you that where you increase the height of the floor you need to think very carefully about how this will relate to the ceiling height. In some buildings I have been to it would result in an unacceptably low ceiling height.

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: Dead cat or pheasant may solve septic tank problem
FROM: Ruby Turner (Nr Hook, Hampshire)
Please can you tell me what will stop my septic tank from smelling, we have recently had it emptied and it still smells, we have tried eco washing powder and dishwasher powder but they don't clean so well? Are non biological soap powders okay?

Ruby Turner

Septic tanks often work best when left alone. They work biologically with aerobic bacteria breaking down the effluent etc. The more frequently you have it emptied the more frequently you will remove the active bacteria and therefore the tank will take time to bet back to full working. This may mean that for a period after being emptied it will smell.

Septic tanks usually have two or three enclosed chambers, allowing for primary and secondary bacterial activity. A "semi-treated" effluent discharges from the end-chamber into the soil or a suitable outlet. Where into soil, it is usually by means of a finger drain. The line of the finger drain may follow a loop of a herringbone pattern and enables the discharge of effluent over a wide area to prevent clogging or flooding.

The chambers for septic tanks are usually of concrete or brick, with an inspection chamber access panel over each. A fresh air inlet is also usually visible and in my experience these are usually tucked away in corners or within shrubbery. Modern septic tanks are constructed in fibreglass with a single manhole. The system of effluent disposal is much the same as for traditional septic tanks but the tank itself is more effective in the disposal of waste matter.

How often a septic tank needs to be emptied depends upon a number of factors. This includes the quality of the bacterial action, the nature of the subsoil, the extent of non-biodegradable material flushed down the toilet, as well as the extent to which bleach and biological washing powders are used and the amount of water going into the one system. On average emptying will take place annually. Cotton wool and paper products degrade very slowly and sanitary products using these materials should be disposed of by other means. Products such as bleach, chemical cleaners and biological washing powders should be avoided or used sparingly as these diminish biological activity. Any other animal or vegetable matter may be beneficial. How you use the drainage system will determine how efficient the system is and how frequently it needs to be emptied. Anything that slows down or removes the bacteria will slow down the degrading process and could lead to a decrease in efficiency and an increase in smells. The timing of clearing and how to properly deal with a septic tank to ensure an efficient system is something that a drainage specialist should advise upon. The problem is probably to do with the lack of bacteria, which was traditionally resolved by putting a dead cat into the second chamber. We would not recommend this, but some meat scraps might do the same thing. You could always seal the inspection chambers with grease until the smell has died away.

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: Should disused chimney flues be vented?
FROM: Mark Kerrison (Norwich)
I have a property built in 1590 and I think I am suffering from masonry paint sealing in damp on one of my gable walls. The problem is how to remove it since the wall is so uneven! The wall is a mixture of flint and brick. I have been quoted 1500 to clean the whole wall using a low-pressure jet system ( but I'm not sure this is the best way to go - damage to the wall being my No.1 concern. I also need to replace two 3ft x 3ft wooden leaded windows and have so far been quoted 2-2,500!! Which I think is somewhat excessive.

Mark Kerrison

Where a surface finish is being removed I always suggest finding a discreet area and trying different methods to find out which will be the most effective and least damaging. Most of these systems have authorised contractors. The contractors usually have experience in dealing with more than one system. It would be sensible to select a contractor and then ask the contractor to do some trial areas using different systems before you decide which one would be best. The alternatives are of course chemical removal and abrasive removal (the latter is unlikely to work in your instance). The poultice based method is by far the kindest and most controllable. Contact Strippers in Sudbury, Suffolk, who may be able to give you more advice.

With regard to the leaded windows you must simply get alternative quotes.

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 flaky & bubbling paint in the cellar?
FROM: Carol Smith (Surrey)
We've recently bought an 1850s Victorian semi detached house. The shared wall in the basement has previously been plastered and painted and I think also some type of damp proofing course has been applied. Bubbles/flaking paint was present at one corner of this wall when we moved in (under the front door steps) -we removed this plaster and polyfillered and repainted it. A few months later the same bubbles/flaking paint have developed futher up the wall. Am I right in thinking that we have a damp problem and that the wall cannot breathe through polyfilla and has migrated up the wall. We obviously haven't tackled the problem correctly first time round, what can we use instead -a lime based plaster perhaps.

Carol Smith

Your basic assessment of the problem seems accurate. Ideally a lime based plaster to allow the wall to breathe should be applied. However, as you mention, this is a shared wall in the basement and the effectiveness of anything you do may be diminished by what might have been undertaken by your neighbours. It would be sensible to speak to the neighbours about works they have had carried out. It is not clear from your description whether part of the area in question abuts soil under ground or whether it is purely a dividing wall between the subject and neighbouring properties. In any event, the advice remains much the same in that you will probably have to look at reinstating a traditional finish.

The problem with attempting to retrospectively damp proof a basement is firstly that such retrospective treatment is not as effective as when incorporated into the original construction and secondly that it does tend to cause the dampness to simply migrate elsewhere and find another route out. It would be sensible to seek further professional advice from someone who properly understands this type of building and these problems.

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: Should we use traditional paints if our property is being repaired with traditional materials?
FROM: Suzy Jackson (Fareham, Hampshire)
Our house was in the Doomsday Book as a storage facility, recorded as residential property in Tudor times. We have specialist plasterer engaged for internal work, using traditional products and techniques suitable for the wattle and daub construction. We'd like to do the decorating ourselves and need advice re "breathable" paints suitable - preferably with a range of colours as the bedroom is rather dark and I'd like to wake up with a sunshine yellow. Can modern products be used, if so what, if not what?

Suzy Jackson

If you have retained traditional materials for repairs etc then I suggest you stay with traditional products and this therefore means forms of lime wash. You should look for traditional lime wash rather than modern "paint" equivalents. Lime wash can be coloured with any pigment to give you a range of colours for decorating purposes. Perhaps a sensible starting point would be the website of Mike Wye Associates (found through this website). On that site you will find guidance on a range of products they manufacture and sell and guidance on the use of the product. With regard to your sunshine yellow, I suggest that a lime wash pigmented with yellow ochre would give you something close to a sunshine yellow (subject to the appropriate proportion of pigment, which always needs to be used sparingly).

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 we clean smoke-damaged beams?
FROM: Robert Hughes (Huntingdon, Cambridgeshire)
We recently had a fire in our Grade II listed Farmhouse which has caused serious smoke damage to the exposed oak beams in the living room. What is the best way to clean the beams?

Robert Hughes

To use any liquid method will probably simply dissolve the very fine smoke particles and take them deeper into the wood. In the first instance I would prefer careful and light brushing using a Hoover at the same time to vacuum the dust straight away. In areas with fairly stubborn smoke staining you might need to use a metal brush but not steel, copper would be more sensible. Otherwise a bristle or hair brush depending upon the ease with which the smoke damage comes off. Unfortunately it is likely to be time consuming but is the only way of ensuring that you do not drive the particles into the wood to cause more permanent staining. A method that involves abrasion is likely to remove part of the original surface. If you are unable to remove the stains to your satisfaction it may be worth considering limewashing the exposed timbers.

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: Severe flooding causes water to come up through the floorboards
FROM: Laura Michalczyk (Dunstable, Hertfordshire)
My grandparents live in a 15th century wattle and daub cottage in Suffolk. They are having terrible problems with damp! Last year they were flooded and water came into the house from everywhere, walls, floors etc. I have read that lining the walls can stop the damp coming in there but what can be done to stop water coming up through the floor?

Laura Michalczyk

If the flooding is due to high ground water in the area, a river breaking its banks, etc then there may be little that can be done. If flooding becomes a regular occurrence it might be necessary to speak to the water authorities about proper flood prevention measures in the district. However, with regard to the immediate locality of the subject property it will depend upon a number of factors as to what might be practical and how successful it might be. In some instances it might be possible to create a slightly raised area in the garden slightly away from the building to help prevent floodwater getting to the building. The problem with this is that it would need to be a continuous barrier around the building and if the floodwater were higher than the barrier created it would not stop the problem. Further, if the floodwater comes up through the ground (the water table increases) then no barrier will stop this.

Within the property itself I would not recommend attempting to damp proof the building. Where such methods have been used in properties what often happens is that is causes accelerated deterioration of the fabric of the building because of moisture trapped behind the impervious surfaces. Alternatively, if water gets in the impervious surface then creates a 'swimming pool' and the water does not get out so easily.

On the limited amount of information you have provided it is difficult to be more specific. At this stage I would not recommend trying to damp proof the walls or the floor as this is likely to lead to longer-term problems.

It would be sensible for a local professional to inspect and advise fully, someone who properly understands historic buildings and the problems of flooding.

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.