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: New cement render starts to fail after only eight years.
FROM: Jim Givens (Lancashire)
I have a 200 year old cottage that has been rendered externally approx. eight years ago. The render at the front of the property is cracking in places and there are hollows when tapped. There is a little damp showing on the inside.

One builder recommends hacking it all off and starting again. Another recommends hacking out hollow (addled) spots - repairing with sand/cement and then coating with one of these "never have to paint - last for 15 year minimum coatings".

Don't want to make a mistake but don't want to pay unnecessarily and endure dust and mess from the first solution if it's not necessary.

Jim Givens

You do not say what sort of render was used, but I suspect it was a cement based material.

It is quite likely that the use of a cement render has trapped some moisture and this is probably the cause of the damp staining. The expansion and contraction of cement render is such that when it expands (not visible to the naked eye) it pulls slightly away from the substrate. At that moment bits of dust, etc. fall down in the microscopic gap and when it contracts it is constricted. Over time the gap will widen. The result over time is a series of hollows and eventually cracks with the render falling off.

I would NOT recommend using a sand/cement render and a modern coating. That is about the last thing you should consider using; it will exacerbate the problem and probably accelerate decay, etc.

You could simply patch repair with sand/cement, but the problem will recur and will not have been solved. In fact if there are buried timbers in the wall you may end up with rot, etc. as well due to trapped moisture.

My advice would be that you consider hacking off the cement render and re-rendering with a traditional lime render. Yes this is expensive and perhaps seems drastic, but it is the only satisfactory long term solution.

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: The property I want to buy does not have an agreement regarding a flying freehold.
FROM: Emilia Price (Cornwall)
The house I am buying is flying freehold. The downstairs front room, belongs to next door, but the bedrooms above it belong to me as the prospective buyer. I would like to know who has responsibility for the roof/walls/front of the house, repair wise. There is no agreement set up in either deeds and the room did originally belong to my house.

Emilia Price

If there is no written agreement it will be a matter of discussion and negotiation. However, as you are buying the property it would make sense for your solicitor to contact the owner of the other part and suggest a written agreement to be attached to the Deeds, etc. Perhaps it would be better to get the vendor's solicitor to sort it out.

The agreement would not be dissimilar to the sort of thing that would be written into a lease. The main structure (external walls, foundations, roof, gutters, etc.) are common and the cost would be shared (I assume a 50:50 split, but this may depend on actual floor areas and practicality, etc.). The ground floor would normally be for the ground floor owner whilst there would be an agreement as to where the boundary lies within the dividing floor.

You will need your solicitor to advise on the sort of thing that would go into a lease, but more specifically I suggest something along the lines of:

Common - foundations, damp proof course, main structure (external and load bearing walls), wall finishes, roof structure and coverings, rainwater disposal system, shared drainage pipes, decorations

Ground Floor - ground floor structure, ground floor ceilings, non loadbearing walls (partitions), all internal wall surfaces (including that to load bearing walls), all other internal parts, décor, services, etc. First Floor - roof space, dividing floor joists and boards above and the rest as for the ground floor (internal stuff etc.).

Windows would normally be for each party to repair, replace, etc., but the decorating of them could be a common responsibility (to avoid a patchy appearance).

Any agreement must include how to deal with both emergencies and routine maintenance. For example, if the roof leaks how to go about it in terms of notifying the other party about the problems and costs, or how to ensure that decoration is dealt with regularly, etc.

The above is merely a suggestion, but gives some idea of how the maintenance responsibility could be split.

If the neighbour refuses you could point out that it is in everyone's interest to avoid confusion and perhaps expensive legal disputes at a later date. If the neighbour still refuses you must consider how to resolve this or accept it as it is or walk away from the purchase.

Of course, before all of the above you should speak to the present owner about how such matters have been tackled in the past. It might be best to get the present owner to initially speak with the neighbour to see if such an arrangement might be acceptable.

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: Potential dry rot problem leads to legal quandary.
FROM: M Dowley (East Midlands)
Despite a full building survey the dry rot which was dormant in our flat was not noticed. It is 17 months later, the developers have stripped back the dry lining of the grade 2 * listed building (at least, where the rot showed), areas chemically treated, some wood replaced. What can we expect in the future and where does legal liability lie?

M Dowley

My first reaction is - was the rot active or historic? Who said it was 'dormant'?

Dry rot strikes fear in the heart of many home owners, but there is much myth surrounding it. Dry rot is a simple fungal growth that requires moisture and nutrients, much like many other growths (think of your common house plant). Deprive it of one or the other and it dies. It can take time to die and if moisture and nutrients are reintroduced during this period it might be revived, but it does not lie 'dormant' as such.

It is said that if you sample the air about you dry rot spores will be found and yet we do not find ourselves surrounded by a sea of dry rot fungus. It is actually a very particular fungus and without the right conditions it will not grow and will either not germinate in the first place or will die out.

I have come across many situations where historic long dead evidence of rot has been 'treated' and repaired for no sound technical reason other than the paranoia of the owner and/or builder and/or mortgage lender, etc.

Please remember that if you took the advice of a treatment company they have a vested interest in selling you chemical treatments and it does not follow that simply because they said you needed to have the property treated that there was actually an active problem. [Read the comments of Matt Green and others on the Discussion Forum]

It is quite possible that you have spent much money and destroyed much historic fabric for no reason at all. On the other hand you may have had a genuine problem. Either way I hope you obtained appropriate listed building consent for the work.

If there was an active problem and the source of moisture has been dealt with, provided you do not have another moisture problem, it is unlikely that the rot will recur.

If you now seek to sue the surveyor and have removed the evidence it could be very difficult. If you have had work undertaken for no good technical reason you will not be able to recover your money. If you did have a genuine problem and can show that the evidence was readily visible to a surveyor competently undertaking a survey you may be able to pursue a claim. However, remember that courts look at diminution in value, not the cost of works. Sometimes you can spend money on rectifying a problem that has little or no impact on value. In such circumstances the court may determine that you suffered no loss as such.

I suggest you seek advice from an independent surveyor experienced in dealing with historic buildings and able to consider whether you might have a claim. You will need to answer whether you gave the original surveyor an opportunity to re-inspect and advise once the problem was discovered and whether you gave an opportunity for the property to be inspected during the works. If you did not give such opportunities you could face problems in proving your claim.


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: Re-revealing my flint wall.
FROM: Jacqueline Penticost (Surrey)

I'm about to purchase an old rectory near Arundel. Much of the building has its original flints walls, but much of the front has been finished in an unattractive render- probably concrete. I'm told the flint walls exist underneath, and I'm wondering how to remove the render, repair the flint walls and make them waterproof. If you could point to any Sussex experts, I'd be grateful.

Jacqueline Penticost

I suggest you read the numerous threads on the Discussion Forum about cement renders on historic buildings. Generally, a cement render is not good for an old building.

Although flint itself is fairly impervious and as a building material does not need to breathe there is a need to ensure that the surrounding mortar is breathable. Flint is a shallow material usually fronting a brick or stone wall and it is like building with tennis balls. If a cement render is put over it moisture builds up inside and usually pushes the flint off. The same applies if a cement pointing is used.

Without seeing the property my advice would be to remove the cement render, repair the flint wall (and this could involve partial rebuilding) then repoint, etc. using lime mortar. This is the best method of ensuring a long life for the wall with no problems. Any attempt to 'waterproof' with impervious materials will result in accelerated failure.

For builders experienced in such matters I would refer you to the Directory on this site (linked to the Building Conservation Directory) where you should be able to find skilled builders in your area. I also suggest you speak with the local Conservation Officer about local builders who might undertake such work (in addition it alerts the CO about the works and he/she can advise on whether they will want a formal application for listed building consent).

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: What will buyers think of my Helibars.
FROM: Luke Villada (Greater London)
We've recently had Helibars strapped to the double bay of our Victorian property with 10 yr. guarantee due to 45 degree cracks appearing to the bay area of our living room.

We are due to put the property on the market shortly and would like to know if these works would hinder any sale and what a surveyor would be concerned about on behalf of their client following these works. Also, we were advised by the structural engineer that this method would prevent any further movement in the bay and that underpinning would not be required. How effective is this method as I had never heard of it.

Luke Villada

You should be up front about the work with any purchaser and/or surveyor and have the paperwork available. It will probably deter some purchasers but a competent surveyor experienced in older properties should not find it detrimental provided it was properly undertaken and the causes of the problem identified, etc.

Without knowing what caused the cracks I cannot say whether the work you have had undertaken has resolved the problem. Inserting Helibars will not prevent structural movement if a different form of structural movement occurs in future. The Helibars will only resolve the original problem. For example, if the original problem was a lack of lateral restraint the Helibars should prevent any future lateral movement. However, if subsidence occurs in future (e.g. from drying out of clay sub soils, etc.) the Helibars will not prevent that different form of movement.

Your engineer should be able to provide chapter and verse on what investigation took place, why he/she reached the conclusion to use Helibars and can therefore justify what was done. If this is the case any surveyor looking at it for a purchaser should be satisfied.

Helibars are commonly used to strengthen walls, restrain walls, etc. They have various uses and it depends on which variety and in what way they have been used as to what they are now doing to make your house sound. However, like any remedial system it will only prevent the problem it has been designed to prevent. If another different problem arises in future the presence of this system will probably have no effect on any new problem.

Provided the engineer has dealt with and resolved all the present movement problems that is all that you can do to ensure that the house is now sound. It is quite possible that the property may never have a structural problem again, but of course it is also possible that like any other property a different problem could arise in future. If when you sell the property a surveyor raises a query simply put the surveyor in touch with your original engineer and let them sort it out between them.

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: Damp in walls persists despite lime plaster.
FROM: Melanie Gaddas-Brown (Durham)
We have a dining room with wooden floor/air vents and has been lime plastered 4/5 months ago - our kitchen is attached and this has a concrete floor, which we were reluctant to dig up as it had been there probably since the 1930s'. We were convinced that we had allowed the dining room enough ventilation, and have not installed a dpc on the advice of SPAB (The house is not listed) - The dining room wall is showing evidence of damp from the floor up to a height of 3 feet in one corner. The construction of this wall is sandstone foundations, with brick/stone rubble fill. We have also drained the garden area around the house. Would you suggest we try the 'real' fire before digging up the kitchen floor or dpc??

Melanie Gaddas-Brown

I am not sure what the fire has to do with the problem unless the damp is showing on a wall with a fireplace in it.

Without knowing the precise nature of the construction of all surrounding parts and ground levels, moisture tables in the ground, etc. it is not possible to provide a diagnosis remotely. You could be suffering from a problem of residual moisture trapped in the wall (especially bearing in mind that it is rubble stone and liable to hold moisture), which once released will resolve the problem. Alternatively, you could be suffering from an ongoing problem of moisture being driven up the wall because of the concrete floor, etc.

It will be necessary to have someone properly diagnose the problem before a solution can be advised. What has been done so far will have helped, but may not yet have gone far enough to resolve all of the damp problems.

Lighting a fire in a chimney will help draw air through and this will help ventilate and dry out a property, but whether this is the solution for your situation is impossible for me to answer without an inspection.

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 fill our hallway cracks?
FROM: Julie Wheldon (Greater London)
Our property is an Edwardian house and around 10 years ago there was subsidence and it was partially underpinned and signed off by the building regulation dept. We recently had a condition survey done for the purpose of buying the freehold and the surveyor noted some cracks on an internal wall in the hallway which he said do not extend through the thickness of the external walls so are 'less significant' but should be monitored over a couple of years to see whether or not the movement is live. We desperately want to decorate the hallway. Are we okay to fill in the cracks and paint over them, as long as we take photographs beforehand with scale?

It seems ridiculous to think we cannot decorate for years for cracks we don't think amount to a problem.

Julie Wheldon

Filling and decorating cracks is often an excellent method of monitoring cracks. If there is no ongoing movement then you will have solved the problem. If there is movement the cracks will reappear and you can then have the matter investigated further. I would therefore suggest that you take photographs, measure the cracks (plot their position from fixed points of reference) and then carefully fill and decorate.

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.