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...

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SUBJECT:
Removing a screed
FROM:
Alex West
(Kent)

We have old farmhouse c1797. Dining room has nasty 1960's quarry floor tiles laid on a very strong mix floor screed. Under all this are original paving bricks which we would like to reveal. What is the best way to remove this screed without damaging the bricks? We are very able diy'ers, just wondering whether its a clubhammer and bolster or a hammer drill job or do you have any other suggestions? Brilliant web site by the way.

Alex West

If the concrete has been laid straight on to the paving bricks without any separating membrane of any description the likelihood is that much of the concrete will be adhering to the bricks themselves. Whatever method you use it is almost certain that many of the bricks will have damaged surfaces upon completion of the work. If there is however a separating membrane you should try to find an edge where the membrane can be seen and to gradually and carefully lever the concrete up from the edge attempting to leave the bricks sound below.

Whatever you find it is often best to carefully and gently hammer the surface to break it slightly but also to break any bond between the concrete and whatever is beneath.

Unfortunately there is no method that I could guarantee would not damage the bricks below. The best I can suggest is that you take care but a club hammer, bolster chisel and levers might be the most appropriate. I would not normally recommend using any mechanical drill etc.

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:
Underpinned buildings should be more stable. So why do insurers consider them more of a risk?
FROM:
Helen Barker
(Greater London)

My partner and I have recently put in an offer on a period (Victorian I think) property. It is a flat on the ground floor of a house which has been divided into four flats. When we viewed the property we were told that the whole building had been underpinned ten years ago and that there had been no movement since. This sounded safe to us,

However, having read up about underpinned buildings, we are now more worried. If underpinning sorts the problem out, why is it more difficult to insure the building? Surely, a building that has been underpinned is safer than one that has had less drastic measures taken to control the subsidence? Also, on average, how long is underpinning likely to be effective for? The guarantee on the underpinning expires in August this year. Is this likely to affect the ability to renew the buildings insurance?

This would be our first property and we absolutely love it. However, we do envisage that we would want to move to something bigger in about six years, so we are extremely worried we might be about to buy something which we wouldn't be able to sell.

We do know that a previous sale on this property fell through last year. We were told this was because the buyer lost her buyer and the chain fell apart. However, another (maybe jealous?) estate agent has indicated that the sale actually fell through because of something to do with subsidence.

Can you give us any advice regarding underpinned buildings and what we need to check to ensure the property is safe and won't become worthless and unsalable?

Helen Barker

Your questions are quite valid and ones that we as professionals often ask as well. You are quite right in suggesting that underpinned buildings should in many ways be more stable and less of a risk for insurers than any neighbouring property that has not been underpinned. Nonetheless it is the case that insurers tend to take the view that underpinned properties are more of a risk.

Unfortunately in the past some underpinning has been undertaken without much thought as to whether it is really necessary or whether it is the most appropriate approach. As a result some underpinning has created more problems than it has resolved. That said, such instances tend to date back to the 1960s and 70s rather than underpinning of more recent date.

Underpinning is simply the creation of a deeper foundation to a building. This usually involves excavating and pouring concrete under the existing footing or foundation thus creating a much deeper concrete foundation. In terms of technical performance underpinning will last as long as the house remains standing unless there is something drastic that changes this. The guarantee for underpinning is no guide at all as to how long underpinning may remain effective. It is simply a way of limiting a company's liability into the future.

What should be remembered when underpinning has taken place is that the original movement would have been caused by something. Underpinning is often undertaken if the cause of the movement cannot be removed or, although removed, there is a risk of ongoing movement etc. When underpinning is designed it has to make certain assumptions based on what is present on site at that time. For example if the problem is one of trees the depth of the underpinning is designed to be such that it should no longer be affected by tree roots. Of course the depth is determined by the presence of the trees that exist on site at that time. If at a future date some other species of tree is planted and the roots eventually grow to a greater depth than the underpinning these could then cause problems, but this is nothing to do with the failure of the underpinning itself rather it would be due to a change in circumstances.

Without knowing why the property was underpinned and precisely what took place it is difficult to give you specific guidance but I hope the above general comments are of some assistance.

Underpinned properties do seem to cause insurers concern. However, there are some companies that specialise in dealing with previously underpinned properties. The Insurance Bureau for example has a specific scheme. I suggest you take a look at their site www.bureauinsure.co.uk. They will require detailed information on the work undertaken in the past and it would be best to ensure that this information is available in any event.

I note that you are buying a property in Greater London and I would point out that much of London and the Home Counties is over a clay subsoil and many instances of subsidence will be found in many streets across the region. Subsidence affecting such properties is not uncommon and neither is underpinning. Provided the matter is dealt with properly and you find yourself sensible insurers etc. I see no major problem and I do not believe you need fear serious problems in future. The property will always be 'blighted' but provided you take the steps mentioned above and ensure that that information is then available for any future purchaser this should help to reduce any problems.

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:
Should I disclose the bulge?
FROM:
John Lawson
(Greater London)

I have a Grade 2 listed building in a conservation area. I bought it 5 years ago. There is a slight bulge in an outside wall and some of the door frames are at angles. I had a survey done on it and they said it is structurally fine. I have always had normal listed household insurance on this house but I am concerned if I am covered by this. I have always ticked the box saying no previous movement as I always thought these features normal for a period property. Do I need to inform the insurer of this? Will they insure me?

John Lawson

Insurance policies cover certain forms of structural movement such as subsidence, heave and landslip. Insurance does not cover all forms of structural movement. There are many causes of movement to a building and bulges in walls are often a result of lack of lateral restraint or some other failure within the structure that has nothing to do with the main insured perils. Therefore in terms of what is covered by insurance the insurance company should not normally be particularly concerned about bulges in walls for which, even if there was an ongoing problem, they would have no liability as such.

That said, if you do not disclose any aspect of the condition of the property to the insurers at the time of taking out insurance they might use this as something against you if you ever had a claim and they wanted to avoid the claim by stating that you had not disclosed certain aspects. Non-disclosure is a major problem with insurance.

If you have a survey from the past and you are now concerned it would be sensible to have that surveyor undertake a reinspection and provide a brief updated report. This should cost far less than having someone else come in.

It would be sensible to write to the insurers and state that as far as you are aware there are no problems of subsidence, heave or landslip (the usual insured perils) but being a historic building there have been other forms of movement on which you have a survey report and enclose that report so they can see what has been said. You should perhaps state in the letter that you hope that this has no impact on their decision to insure but would appreciate their further guidance on matters or request for further information etc.

It is always best to notify insurers so that you avoid the accusation of non-disclosure if you ever make a claim at some future date.

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:
Cracked ceiling beam
FROM:
Stephen Flint
(Oxfordshire)

Cracked ceiling beam: Do you have any advice for a cracked exposed ceiling beam? Our first floor is supported by a large central oak beam with smaller beams going off to tie in with the walls. The problem is one of our smaller beams is cracked from bottom to about 1 inch from the top and flexes somewhat when ever anyone walks over it. It has been there a while and does not look as though it is getting any worse although has been on my "to do" list for some time

Possible solutions I thought of were:

1: Replace the beam with a similar reclaimed one

2: Add a wooden support from floor to ceiling, although as this would correspond to the middle of the window I'm not keen

3: Use "aged" steel plates or barn door hinges and coach screws to create a strap for the beam

Stephen Flint

If the building you refer to is listed whatever method of repair you choose should be passed by the Conservation Officer to ensure the officer is happy with the method selected.

The simplest method is simply to provide a prop to the beam from below but of course this is the most disruptive and visually unacceptable. If there were an urgent need to provide support this is however probably the best way of doing so.

Replacing the beam is the most extreme as it involves removal of the historic fabric and the installation of new fabric. What might make the problem worse is to use a reclaimed beam as one could regard this as attempting to falsify history by using a salvaged piece of timber. There is no reason why a new piece of timber should not be used so that it is an honest repair.

Without seeing the beam in question it is difficult to say which method is most appropriate. However, my favoured method in such a situation is to use carefully designed steel work sometimes concealed to the upper surface underneath the floorboards or alongside the beam. It should be possible to find a way to install a steel plate alongside the beam bolted through the beam to strengthen it or underneath the beam and bolted through to provide support (depending on the nature of the crack etc.).

In some instances a slightly weak floor can be strengthened simply by using long fully threaded screws to screw through the floor board into joists from above. This mechanically fixes the boards to the joists and instead of the joists and boards working independently they become a T-beam and the whole floor becomes a diaphragm structure and therefore much stronger. This is a method that has been used quite successfully on some historic buildings but of course you need to be careful in selecting the screws to use and how they are positioned etc. so they are not too obvious from above especially if the floorboards are very nice old floorboards that are on show and are aesthetically very pleasing. You should also note that the screws should be placed at about 150mm centres along all joists to be most effective in strengthening the floor.

I hope these comments on the various methods are helpful but from your description my preference would probably be for metal plates.

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:
Cob house with a crack
FROM:
Katharine Bailey
(Devon)

We are looking at buying at Grade II listed cob house but in the upstairs bedroom there is a 1" gap down the right angle joint of the two exterior walls - all the way down and along the floor. There are also severe cracks down the upstairs walls. From an amateur observer, it looks like the cob house may not have any foundations and the wall is slipping away. Please could you advise what would need to be done to sort this out? Would the entire exterior wall need taking down and replacing and/or would the whole need underpinning in sections to secure it's foundations? Any idea of how much this work would cost?

Katharine Bailey

If you go through the discussion forum of this site you will find threads where the issues of cob buildings have been discussed at length. Cob buildings pose a particular problem. Quite often cob buildings have been inappropriately rendered and repaired or dealt with over the years. There have been many instances of catastrophic and sudden failure of cob buildings. The fact that this building has such a gap and crack in it indicates that it probably has a very serious problem.

As you are thinking of buying the property I strongly suggest that before you take any further steps towards the purchase you should seek the advice of a professional who properly understands this type of building. On the web one organisation based in East Anglia but dealing with similar types of building is Eartha and their website is www.eartha.org.uk and I suggest you have a look through that website. However, closer to home for you would be reference to the Devon Earthbuilding Association and their website is www.devonearthbuilding.com

It is quite possible that parts of the building will need to be reconstructed. Without knowing the extent of the work necessary and what else may be involved it is impossible to give you any sensible indication of cost. However, a specialist in cob should be able to assist you on this matter.

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:
Can we change the colour of our house?
FROM:
Sally Timms
(East Sussex)

We own a Grade II listed property, which currently has white weatherboarding and black painted windows. We need to have the exterior repainted and we are unsure if we can change the colours without the need to go to planning? We would like to paint the weatherboarding cream, and the windows either chalky white or perhaps a grey/blue off white colour. Would you know if changing the colours in this way needs approval from our local planning authority?

Sally Timms

This is an issue that has caused much discussion in the past and has even hit the news headlines over the years. The sort of change you mention seems quite acceptable but without knowing the property or the local policies it would be inappropriate for me to say categorically whether you could change the colours without consent.

The most sensible thing to do would be to speak with the local Conservation Officer. It may be that with your particular property the colours are not considered a significant issue provided they are kept muted and in keeping with the general tone of colours used on buildings in the region. The issues that hit the headlines tend to be where people want quite radical changes in colour. I therefore doubt that you will have any major problem but I strongly recommend that you speak to the Conservation Officer before taking any action. Whether you will require a formal application is something you would need to discuss with the officer. With something like this it may be that the officer would accept a simple exchange of letters as being sufficient not for formal consent but simply to keep them informed.

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:
Natural insulation for lightweight timber frame
FROM:
Sally Morton
(Essex)

We have an 18th century cottage with lightweight timber frame. Previous owners in 1988 reclad the exterior with featherboarded painted softwood over a good quality breather paper but did not include a plywood layer or batten off, i.e. the breather paper and cladding are attached directly to the frame. We have removed the internal plasterboard and the glass fibre wool that had been stuffed between the studs, but which was sagging against the breather paper causing condensation. We have been advised to put small battens on the inside of the breather paper irregularly spaced to create an air space and allow air flow. Would prefer to use natural insulation but can\'t find relatively thin (50mm) rigid material for stud infill, and need to consider weight. So,what about Celotex GA3050 or similar in between the studs, depth 50mm. On the inside of the studs sheet with 12mm Celotex T3000 to provide a thermal break across the studs and then a plasterboard backed with a vapour control membrane. Does this work? Concern is "breathability".

Sally Morton

It would be inappropriate for me to design a system for you without seeing the property and considering all factors. It is generally correct to state that if there is insulation within the wall void there should be a ventilating gap beyond this to help prevent condensation problems etc. You mention a breather paper but is it a genuine breather paper because in 1988 it is more likely that a building paper that gave provided little permeability might have been used?

Although it is correct to state that glass fibre does tend to sag you could look at using Thermafleece as this can be supplied in batts that might remain rigid enough for vertical use.

The main issue here is how important breathability is for the building. If modernisation in the past has resulted in a building that is generally not particularly breathable then the use of modern insulation etc. might be an appropriate and cheaper method of upgrading the building. However, you should bear in mind that modern insulating materials such as those mentioned are not as breathable as natural materials such as Thermafleece.

It is quite clear from your description that there is a modern finish to the exterior and a modern finish to the interior. Therefore the only historic part remaining is the concealed frame within the wall structure. The breathability of the structure in terms of the finishes is therefore not particularly an issue. The main issue is designing a system that does not lead to accelerated decay of the historic timber frame that remains.

If the property is listed you will need listed building consent and you will need to speak to a Conservation Officer.

I strongly advise that you seek further input from a professional experienced in dealing with this type of building that can inspect and provide property specific advice.

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