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).

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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...

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SUBJECT:
Erupting sandstone
FROM:
David Anderson
(Scotland)

I live by the sea in a Victorian house with sandstone edges. The sandstone is "erupting" in places, possibly due to water? How can I repair this? Some experts recommend a lime mortar and others warn not to use it in proximity to the sea

David Anderson

The description you provide suggests that over the years the sandstone has absorbed moisture containing salts and when the moisture evaporates the salts crystallise and therefore expand causing damage to the sandstone. This is usually referred to as "spalling".

If the building is listed you will of course need to seek consent for whatever finish you wish to apply to the building. Whilst a render over the surface might provide some protection it will be affected by the salts much the same as the stone itself. Similarly any paint or any application direct onto the face of the sandstone. Whether it be a paint or a render or anything like that there is always a danger that moisture will get behind it at some point and if this happens and as the moisture evaporates the salt will cause the same sort of damage as at present. However, with impermeable finishes the moisture will not evaporate so easily if at all and could cause additional damage.

This is not an easy problem to resolve but in extreme circumstances it might be appropriate to consider a cladding to the building, or at least to the elevation in question. For example it might be appropriate to consider installing a slate cladding or perhaps a hung tile cladding. This would create an outer face to the wall that would provide the necessary protection whilst leaving the sandstone behind relatively untouched. In the situation you described there is probably no right or wrong solution as such but a matter of trying to find something that protects the sandstone from further damage without exacerbating the problem.

My views on this are as set out above in that an independent cladding might be the most appropriate. You should accept however, that this could significantly change the appearance of the building although bear in mind that the cladding itself could be painted or rendered in some way to provide a required appearance. What you are effectively doing is creating a protective barrier that does not result in creating problems behind it. Alternatively you could create something that might in itself be sacrificial (e.g. a render finish) to protect the sandstone behind. In any event you will probably find that whether cladding or render they will deteriorate and be occasionally replacement will be necessary. I hope these thoughts are of some help to you.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
Restoring a brick floor
FROM:
Rebecca Crawford
(East Sussex)

We have uncovered a brick floor in our lounge and would love to restore it, have you any advice on how to do this? In particular how to clean it as it currently has bits of carpet underlay, glue and cement on it? Also I'm not sure what to use in between the bricks - it currently has sand of some sort between the bricks and finally what to finish it with?

Rebecca Crawford

Where remnants of glue and cement are fixed on old bricks it can be extremely difficult to remove these. For some glues there may be solvents that will remove the glue and for cement there are some removal chemicals that might take some of the cement away. However, most of these cleaning methods result in bricks that may not be suitable for leaving exposed because the surfaces will be damaged. In some instances the cleansing liquids/solvents get absorbed into the brick and can mar the appearance.

I suspect that you will have to face the fact that some of these bricks will not be capable of cleaning and being saved. You might have to replace them. Alternatively, if they can be lifted you should check the lower faces to see if they are in a condition that could be brought to the surface so that you simply turn the brick over. It is unlikely that this would be successful but before simply replacing (with suitable matching second hand bricks) you could look at this as a possibility.

From what you describe it seems that the bricks are probably laid on earth and finished with sand brushed between. You could mix sand with a small amount of lime to neatly point up between the bricks but it is important to maintain a breathable finish.

On the matter of what to finish it with I suggest that you leave it unfinished as any modern sealant will create problems in due course and at present it is probably important to allow moisture to evaporate and to allow the brickwork to dry out over time.

It would not be appropriate to completely cover with carpet or other floor coverings but you might wish to lay rugs over the surface and occasionally lift them so that the brickwork underneath can dry out.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
Damp caused by neighbours concrete path?
FROM:
Simon Dearnley
(Lancashire)

I own a block of 3 Victorian terraced houses built in 1896. One of the end properties has a problem with damp on the gable end. This problem is not on the other gable end. The damp is at the lower part of the wall rising approx 1.5 metres above internal floor level. In the past the wall has been re-plastered indicating to me there has been a problem before. There are also signs that a DPC has been injected and among the paperwork I have an old Guarantee for a DPC injection done 26 years ago. The damp patches are causing black mould to grow on the internal surface and the entire gable wall at this level feels damp and wet to touch. If I drill into it the dust comes out mixed with water. The construction is of red brick cavity wall rendered on the outside with a black paint applied. I suspect this was another effort to alleviate the problem. On the outside the gable wall forms the boundary of my land. I don't own the land that immediately butts up to my gable wall. In the 1960`s a semi detached shop building was erected approximately one metre away from my gable wall with its rear back to back with my gable wall. Between my building and the shop units there is a concrete alleyway. The finished level of this concrete is half a metre above the finished floor level in my property, which is a standard timber suspended floor construction to the front half of the property and concrete to the rear. Would I be right in thinking that the construction of this concrete path above the internal floor level in my property has caused this problem? The DPC I mentioned earlier which was installed 26 years ago has plugged holes on the exterior approx 12 inches above the concrete path. In my amateur opinion this would have been a complete waste of time considering it is well above the internal floor level. Maybe this is why it isn't working? Would I be correct if the problem is the neighbours concrete path that has caused my problem, that they are responsible to lower their path and repair my damage, even if they were not the owners at the time of construction of their building? I also note that when the concrete was laid, they have made a sort of six inch wide slope away from my property into a grove as if to keep water away from my property.

Simon Dearnley

You raise a number of issues in your question.

Dealing first with the matter of damp - I would advise you to have a professional experienced in dealing with damp problems in this type of building to inspect and advise fully. You need to find someone who would not have a vested interest in any recommendation they might give. On the discussion forum of this site there are such specialists (e.g. the poster known as PC) or you may find some building surveyors in your area that are able and willing to advise independently on the problem of damp.

You describe what you call a cavity wall but it is not clear to me whether it is a genuine cavity wall or in fact a solid brick wall. The important thing is that the wall appears to be constructed of conventional soft red brick. You mention high ground level outside as well as a coating to the exterior that sounds as if it is probably an impervious finish. You also mention evidence of a chemical injection system installed some years ago.

It does sound as if the high ground level may be the primary cause of the problem and that the works undertaken since, such as the injected damp proof course and the coating to the wall, have been attempts to resolve the problem. Unfortunately I suspect that these attempts have actually exacerbated the problem.

The mould you note is indicative of a condensation problem. This is probably where the wall is cold and damp and the excessive moisture is unable to escape and eventually appears as condensation. Warm moist air within the property probably condensates as it hits this colder surface.

The obvious and most appropriate solution would be to lower the ground level and to remove impervious finishes so that the wall can breathe and moisture can evaporate away before it causes any damage and the wall can function as was originally intended. However, if for any reason this is not practical and cannot be achieved you may have to face the fact that there will be dampness at the base of the wall and therefore the problem has to be managed rather than remedied. If this is the case you might have to consider some form of drained cavity system to face the wall internally. This means that there will be moisture in the wall but when it reaches the surface it is behind a membrane or dry lining and can drain away and evaporate or be positively removed. To the surface that you see within the room there will be a plastered or otherwise decorated finish that is not affected by the damp and if necessary you can incorporate some insulant within this finish to improve the insulation of the wall and reduce the problem of condensation. You could use a traditional dry lining system but it might be more appropriate to consider a modern drained cavity membrane (e.g. those produced by Proton, Delta, Newton)

It is of course always difficult to try to analyse a damp problem such as this without photographs and without actual inspection but from your description I hope the above gives you some pointers as to what might be necessary. Nonetheless I strongly advise you to seek professional advice before tackling the matter.

With regard to legal remedies against the neighbours, it may be that you have a case to argue that the high ground level is causing a problem. A case such as this has been taken through the legal system by a landowner with a local highway authority in recent times. It was settled out of court but in principle the Highway Authority did accept responsibility. I am not suggesting that this sets a precedent but it could well be argued that your neighbour (even though in this case the neighbour was not the person who undertook the work) could be liable for the damage being caused to your property. This is of course something upon which you must seek legal advice before taking any action.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
Damp in Dorset
FROM:
Helen Dodd
(Dorset)

We live in a cob house in Dorset and suffer from rising damp in the living room and one of the upstairs bedrooms - only on the external wall - to the extent that the skirting board is coming off downstairs. All the external walls have been re-rendered using a lime plaster and we have a dehumidifier in the bedroom but we still have very damp rooms, mould around the upstairs windows and salts on the walls. We know we need to lower the patio outside the living room to bring it below internal floor level but will this solve the whole problem? Is it necessary to have tanking or some sort of ventilation system fitted in the living room - and if so how do we go about this?

Helen Dodd

May I firstly advise that you probably do not suffer rising damp in an upstairs bedroom.

If the building is a genuine cob structure and is suffering from the levels of dampness you suggest I would be extremely concerned about the structural integrity of the building.

You mention that the walls have been re-rendered using lime plaster but it is not clear from this what damage you found to the cob beneath.

Your description suggests that there could be a condensation problem in the property in which case improved ventilation should go a long way to help. The most helpful form of ventilation would be to extract warm moist air from kitchens and bathrooms.

A de-humidifier can be of use but if it is simply containing the water within its own unit the moisture is not actually being removed from the property.

You do not say what finishes are found on the internal wall surfaces and it may be that if there are modern plasters and perhaps even a tanking render etc. that these would be exacerbating the problem internally. A cement based tanking render will be quite cold relative to traditional lime plaster and condensation could form on it if it is a cold spot.

My advice is that you should seek independent professional advice on the problems. You need to find someone that understands cob buildings and can provide you with detailed advice on appropriate works. Without an inspection of the property I can only give very general guidance.

I would point out that there are associations of professionals and owners dealing with earth buildings. One particular association that you could speak to is Eartha and their web site is www.eartha.org.uk . Although they are primarily interested in earth construction in East Anglia they do have contacts throughout the country. Closer to you is the Devon Earth Building Association and their web address is www.devonearthbuilding.com

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
Inappropriate paint on lime render
FROM:
Andrew Miller
(Suffolk)

My house mainly has lime render on it, and is lime-washed. But on one section, the previous owner has painted it using standard masonry paint (I found a can of Sandtex in the shed, so it's probably that). The underlying structure is a mixture of brick and flint, probably in lime

Near ground-level, the paint is peeling off, probably due to damp getting underneath it. So my plan is to scrape it all off and lime-wash it. However, it looks like the further I go up the wall, the harder it will be to get the paint off. I don't want to end up removing too much of the render as I might do more harm than good.

Is this the best thing to do, and if so what is the best way to remove the old paint?

Andrew Miller

The simple answer to your question is yes it is a good thing to do to remove inappropriate paint. Where it is flaking and easy to remove the problem is simple to remedy. Where the paint is well-adhered and difficult to remove you could cause damage if you're not careful. The best way to remove the paint is chemically and I would suggest that you contact Strippers who are based near Sudbury in Suffolk and therefore not too far from you. The web address of Strippers is www.stripperspaintremovers.com

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
Ongoing odour from original wet cellar
FROM:
James Bradley
(Norfolk)

We have a Grade II listed semi-detached former public house dating back to 1750. Our half of the building possesses an original wet cellar that was filled with builders waste about 30 years ago. When we moved in there was a very unpleasant smell in the house and in an attempt to remedy it we had the old cellar re-opened. A collection of oil residue was found in the base which was removed and the stone cellar walls were cleaned with detergent and water (as directed by the listed buildings authority). We have subsequently had this cellar dry-lined to make it useable but fear that leachate from the cellar fill is diffusing through the remaining floor of the house leading to an ongoing odour. I wonder if you have any advice or know of anyone who could give me advice on what to do next

James Bradley

This is indeed an unusual situation and one that I have not come across before. If you suspect that oil has leached through under the building and is causing the unpleasant odours throughout the house you will need to seek advice from a company specialising in clean up following oil spills.

This is not dissimilar in some ways to dealing with contamination by oil and therefore a specialist in dealing with contamination and environmental matters might be most appropriate in this particular instance. In terms of surveyors that might be able to assist you the RICS does have an environment faculty and this includes matters such as contamination. If you look at the public side of the RICS website (www.rics.org) and search for surveyors in the environment faculty in your area you should be able to find someone who could assist you and provide further guidance on this matter.

Remember that when cleaning up oil it usually involves use of other chemicals that may then in themselves need to be cleaned up or disposed of in some way. When speaking to someone about dealing with this problem they should be made aware that it is a listed building and that apart from removal of the oil and removal of the smell there will be the issue of the impact of any chemicals they may use on the historic fabric of the building and all these issues have to be carefully considered. It may be appropriate to therefore also incorporate a professional who specialises in dealing with historic buildings for the two professionals to work together in this matter. Listed Building Consent may also be needed before the work commences.

Period Property UK would like to thank Stephen Boniface, Tony Redman and other partners at The Whitworth Co-Partnership for responding to this question.
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SUBJECT:
We can't put our curtains up!
FROM:
Jonathan Tyler
(Worcestershire)

We have just moved into our first house which was built in 1880 and still has the original plaster on the walls. So far every attempt to drill and plug the walls has failed as the plaster breaks up as soon as you push the plug in. Rather than replastering is there any special technique we can use to get plugs into the wall to put curtain rails etc up?

Jonathan Tyler

You do not mention what construction the house is built from. It sounds to me as if you are trying to fix into the plaster itself rather than into the wall structure.

If the building is of brick construction you probably simply need to drill deeper through the plaster so that the rawl plug and the fixing is into the brickwork behind. If the walls are lath and plaster you may need to carefully drill through and use a fixing such as you might use on a plasterboard wall in other words one designed for hollow walls. However, if you can find timber studs to fix into this would be far more appropriate.

With the best will in the world it is quite likely that the plaster will be damaged as you drill through it. For small areas of patch repair such as this I see no problem in using conventional Polyfilla (or similar) to make good.

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