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 (www.periodproperty.co.uk).

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: Period dream turns into maritime adventure in our own house.
FROM: Sharon Gould (Hampshire)
15 months ago we purchased a thatched chalk and flint cottage - oldest part 1606, with two extensions built in the 1980's. The vendors 'forgot' to mention that they had flooded before due to the high water table, and we now have water coming up under the sub-floor in the oldest part and seeping through the concrete floors in the other parts. We have discovered two large sumps in our driveway and are currently pumping out @ 700 litres a minute. This is keeping the water out of the house at the moment - but what can we do going forward to prevent it happening again. The floors of the house are about 8-10" below ground level. We are both devastated by this - we love our house but we wish we had been told about the problem before we purchased - the insurance company and our solicitors are dealing with the legal questions - but in the meantime we have to find a way of resolving the main problem - the high water table. pull down ladder!

Sharon Gould

This is an increasingly common problem - not necessarily due to 'global warming' etc, but more likely to do with the fact that development of land, road building, works to rivers, etc have caused changes in where ground water runs and its depth below ground level. A part of the problem is development on flood plains, but I doubt if this is the whole story. It is a combination of factors, but in simple terms ground water has less permeable soil to run through and/or there is more ground water due to increased rainfall. In any event, the ground water will naturally rise to a higher level. The bottom line is that it will not change overnight and we have to find a way of dealing with it.

In the first instance I suggest that you consider lowering the ground level around the building. Not just forming a channel, but major ground lowering for some distance away from the building. In conjunction with this it might help to install a series of land drains to positively direct water into water courses that can take it away. It may be necessary to look at a permanent pumping solution, in which case you need to liase with your Water Authority. In any case, you should speak with the Water Authority and the Rivers Authority in case works have been undertaken (or not undertaken) in your area that affect the ground water generally. You are probably not alone in your suffering and it might help to get local residents and landowners together to speak to the Authorities about permanent solutions.

A borehole could be taken in your land to establish precisely what soils exist, their permeability and the ground water level. I know of some situations where a drain hole through an impermeable layer (e.g. clay) to a permeable layer (e.g. chalk) has helped resolve a high ground water problem. These are issues that the Authorities should be able to advise upon. Internally, if necessary, I would favour a drained system of dry lining the walls and floors - provided it is properly designed. This should give you dry internal walls without detrimentally affecting the way the structure functions regarding dampness. However, if the structure is suffering from excessive ground moisture it might need a more robust solution that involves giving it protection. That said, if the vulnerable parts of the structure are sufficiently above ground level they should not suffer - hence my advice to lower ground levels around the site. I hope this helps - let us know what happens, as I am sure others are concerned about the increasing incidence of high ground water.

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

 
 
 
 

SUBJECT: Bad odour gives rise to concerns.
FROM: Mrs R Cant (Berkshire)
We have moved to Victorian property with a septic tank. Although it was emptied 6 months ago, we consistently have had wafts of bad odour since then. Is this normal?

Mrs R Cant

The tank is not the only part of the system. 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. It is possible that these are blocked and need clearing. However, more important is that you understand how these work. Septic tanks usually have two or three enclosed chambers, allowing for primary and secondary bacterial activity. 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. How often a septic tank needs to be emptied depends upon a number of factors. On average emptying will take place annually - too often and the bacteria do not 'get going' and yet too infrequently and the system can become blocked. Some tanks are so efficient that they hardly ever need emptying. The efficiency will depend on factors such as 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. Cotton wool and paper products degrade very slowly and sanitary products using these 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. This therefore affects whether it is efficient and whether it smells. Consider how you use the system and adjust, if necessary. Have the whole system checked - there may be a partial blockage somewhere else that is resulting in the smells.

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

 
 
 
 

SUBJECT: Damp barn wall remedy required.
FROM: Nigel Sarbutts (Lancashire)
I'm about to convert about a third of the barn which adjoins our house. The gable wall is damp on the barn side, but dry on the house side. The barn has a concrete floor with membrane which will probably have to come out any way. What should I replace it with to reduce future damp problems (ending up with floorboards) and how can I deal with the wall which is and isn't damp? The gable and rear wall have previously been underpinned for some unknown reason.

Nigel Sarbutts

Unfortunately this is insufficient information to give you full advice. Regarding the floor, I would favour a traditional floor without a membrane that enables the floor to breathe. There are ways of meeting regulation requirements without a membrane - I recently spoke to a builder in Hertfordshire who had devised a method that involved the use of horticultural insulating beads (ceramic I believe) to give the floor its insulating value and a geotextile membrane to allow a degree of breathability. You need to speak to an architect or surveyor with some experience in dealing with old buildings.

If you want a timber floor the best way to achieve this is to create a suspended timber floor (insulated) with ventilated void beneath - if you have the depth to enable this. You do not say what the damp wall is constructed from. The damp could be condensation that is appearing on one side of the wall only. The wall might contain moisture, but the warmth on the house side could be keeping the house face dry. I would prefer to avoid any form of damp treatment until the cause of the damp is properly understood and a suitable approach devised that enables the wall to continue functioning properly without having a damp surface. Again, speak with someone local who properly understands old buildings.

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

 
 
 
 

SUBJECT: Who do I contact to help me match limewash with the buildings original stone colour?
FROM: Lynee Vitale (Glastonbury, Somerset)
Should I buy a 200 year old cottage with history of rising damp and woodboring insect attack. Both were treated in 1987. This is my first house purchase and I am very unsure.

Lynee Vitale

Show me a house of that age without a history of insect attack! It would be rare. However, does that matter? Not if the infestation is not doing structural damage, or if the environmental conditions in the property are adjusted such that the infestation naturally dies out (warmth, ventilation, etc). Only if the attack is causing damage does it need more robust treatment (possibly chemical treatment) - but even then only localised targeted treatment. Unless the attack is major I usually suggest that owners target treat timbers affected as and when general building work is undertaken and the affected timbers exposed.

Turning to the matter of damp - who said it was rising? Many older properties have levels of moisture that are higher than modern houses. This is not necessarily a problem and if it were not for the sensitivity of the modern moisture meter we would probably never realise. What damage is the damp doing? Are there obvious causes, such as leaks? Is the ground level high, or is the wall surface coated with an impermeable finish that prevents the moisture from escaping naturally? Many properties I inspect that are said to have a 'history of damp' are simply properties where the problem has not been properly assessed and past treatments have therefore been ineffective - because they are trying to treat a form of damp that is not there. Get someone who understands how old properties function and get them to find out what the cause is and what to do about it.

A word of warning to all 'new' purchasers of old houses - mortgage valuers are often told to alert purchasers to the presence of rising damp and the need for further 'specialist' reports if their moisture meter gives any slight sign that there might be damp. They are not there to assess damp problems, etc so don't rely on a mortgage valuation as being an accurate or correct commentary on condition. They are basically told to 'pass the buck' if they even suspect a problem. Unfortunately there are too many who 'have the buck passed to them' who do not understand old buildings.

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

 
 
 
 

SUBJECT: Should I use a modern waterproofing coating for my stone wall?
FROM: Paul Hancock (Stoke on Trent, Staffordshire)
I have a building which is an old converted stone barn. The gable end is the weather end and is soaking in the rain producing running water on the inside. I have considered the following:

  • Spraying the outside with a waterproof coating
  • Lining the inside with a false wall of thermalite blocks which I could then plaster
  • Using the damp proof membranes I've seen recommended on the Internet.

What would you suggest from these three or would you recommend an alternative?

Paul Hancock

On the information to hand - perhaps none of the above. A stone wall is a natural structure and it is permeable. If it gets sufficiently wet water will come through. That is how is has functioned for all its life to date and how it functions best. However, that is not always convenient for modern domestic living and we need to find a solution that suits both you and the wall. Treating the outer face will seal it up for a time and cause no end of problems. You will have to periodically re-seal anyway - that's if the stone doesn't simply crumble away - an overstatement - but a possibility!

Lining the wall internally could work, but you will lose floor space. If you end up going down this road consider using a modern drained cavity system [Is this the 'membrane' you refer to?] in conjunction with an insulated dry lining.

Historically, the way exposed buildings were protected from rain, etc was to provide a form of cladding. In some areas this would be tile hanging, in others it would be shingles or weatherboard. The idea being that the wall is basically left alone but a cladding placed on the face to protect it. This gives direct protection without sealing it up and the wall is therefore still able to breathe. However, in the first instance the most appropriate form of protection would be to apply a limewash or lime mortar. This would give added protection whilst allowing the wall to breathe. You need to get advice from a local professional experienced in dealing with old buildings. Remember, if the building is listed you may need listed building consent for some of these solutions.

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

 
 
 
 

SUBJECT: Can I construct a new doorway in a lath & plaster wall?
FROM: Julie Joss (Andover, Hampshire)
Can you tell me the best way to cut a doorway through a lathe and plaster wall?

Julie Joss

Do not assume that simply because it is only lath and plaster on a timber wall that it is not a main structural element! Many older buildings have extensive timber structures internally. If the building is listed - have you got consent? Assuming that you have consent and that the wall can take a doorway without detrimentally affecting the structure I suggest the following.

Carefully remove the plaster and laths to expose the timber frame. Cut through the plaster around the area you wish to expose. Remove the plaster from within the cut area. If you simply pull off the plaster it will loosen surrounding areas that you may wish to retain. Carefully cut away the laths once the plaster has been taken off. Establish where you want the door but DO NOT cut through braces - the diagonal timbers - to install the door. Carefully cut through vertical timbers that are 'in the way' provided they are not the principal members of the frame. Install a trim timber at the head of the opening and then install vertical timbers to the width of your doorway. Line the opening and hang a door. This is very simplified. There are many DIY books that deal with the basic installation of a doorway. I hope this is nevertheless what you wanted.

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

 
 
 
 

SUBJECT: Darling, there's a Squirrel loose in the bedroom.
FROM: Carol Granger (West Sussex)
Our cottage (early 1800's) has 2ft solid stone walls of sandstone facing on solid ironstone and a pantile roof. The roof timbers sit on top of the solid walls and the eaves under the roof are open all the way around the house, allowing free circulation of air through the loft but also allowing squirrels free access, despite regular replacement of wire netting. The loft is well lagged. Are there any risks involved in closing off the eaves with wooden panels, such that there is no circulation of air above the tops of the walls, for example could this encourage rising damp? We believe the ground floor, which is a solid floor, is 'tanked' and the only damp problems we have are around leaking guttering.

Carol Granger

I noted recently that in the professional press there is some debate starting about whether to ventilate roof spaces. If the roof space is very large and there is no lining to the roof slopes there should be sufficient natural ventilation that closing off the eaves should not be a problem. However, I suggest you use a system that could easily be taken down for maintenance and occasional inspection (i.e. screw the boards in place - so that they can be unscrewed easily). As an alternative - how about using galvanised steel mesh? It may depend on the size of the gap and its appearance, but with small areas I find this to be a satisfactory solution. If your roof is lined and/or small I would prefer to see the eaves retaining some ventilation. You could, of course, drill a series of small holes in the boards - large enough for ventilation but too small for most vermin. This is labour intensive, but a reasonably aesthetic solution - especially if you drill some nice patterns!

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

 
 
 
 

SUBJECT: Noisy neighbours disturb cottage tranquillity
FROM: Richard Flack (Norwich, Norfolk)
I have a party wall where the previous owner has removed the lath and plaster to reveal the original timbers. Looks good but noise insulation is minimal. I need to address the problem to afford some privacy (normal levels of conversation are clearly audible from next door). Should I just replace the lath and plaster or can I get far better sound insulation by, for instance, erecting a secondary stud wall using modern sound insulation board?

Richard Flack

Either way, the work might come under the Party Wall etc Act 1996, in which case you will need to liase with your neighbour, serve formal notice and generally comply with the act. As the work will presumably cross over the 'line of junction' you will have to get further advice on the implications of the work. In any event, if it benefits your neighbour as well, will he/she not contribute to the cost? As the wall is internal the breathability of the wall is perhaps not such an issue as if it were external. I therefore suggest you consider filling the void with an insulating material. Several of the manufacturers make an insulating 'batt' specifically for sound insulation. This can be cut to shape and placed in the voids before the face of the wall is re-formed. Density is the thing that generally provides sound insulation. However, some structures can transmit sound. To reduce the risk of the wall face acting like a drum (in the case of using plasterboard) you would have to consider mounting it on an isolating material. That said, lath and plaster is quite dense and I suspect that if you insulate the voids and then reinstate traditional lath and plaster you will find that sound transference is greatly diminished.

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