Some of the pitfalls of listed building ownership and the need for professionals

If you're new to the concept of listed buildings, or are currently thinking about having work done to yours and are not sure about which materials to use or the possible legal implications concerning alterations (however minor), then this is for you. 

The definition of what it means to be a listed building owner is one which states that you are charged with the guardianship of the building. You might own the title deeds but your ownership is in name only. The Conservation Department of your local council can exercise its rights over you as far as upkeep, maintenance and alterations are concerned. There's just so much you can't do so if you're desperate to knock down walls and put your modern stamp on an old building then it might be wise to look for something which isn't listed. 

The aim of this article is to give owners and potential owners a greater understanding of their rights and responsibilities. Hopefully it will enhance the ownership experience and help you to add value to your house whilst making it more saleable. 

Firstly, contractors. With ready and willing hands only too eager to pocket a pile of hard earned cash in exchange for some inappropriate work it’s rare that one comes across a listed property which has not had the addition of cement for rendering and repointing over the last 50 or 60 years. In fact, it’s likely that 98% of listed buildings have had the wrong materials used on them at some point. Not only might the house come with the addition of icky cement, you may also find walls covered in gypsum and none breathable or plastic paint. If you're in the market to buy and you spot that gypsum might have been used then make a note and ask your surveyor to check it out. Look at the walls and if they appear really flat - a smooth almost mirror finish - then this might be evidence of a gypsum plaster. Check to see if an effort has been made to make the interior look as smooth as a new build and bear in mind that an uneven surface is actually a good sign. Don’t be afraid to ask the vendor if they can prove they instructed a contractor who used lime – an old invoice could go a long way to dispelling fears. If gypsum has been used then it might be worth asking the current owners to consider a reduction in price as it means there will  be  trouble ahead as gypsum will only last a few decades and will blow once moisture gets behind it. It will also crack where there's even just a fraction of settlement.

A more common and quick to appear issue of modern plaster is the fact that condensation rapidly gives rise to mold. The problem being that it will hold moisture but is not porous enough to aid its evaporation.This is because gypsum plaster is actually very porous but not in a good way. Think of a sponge and how it holds on to moisture.

If the pink stuff or cement has been used in any area of the house then consider how much its removal might cost as it could be an expensive job or a time consuming pastime for you. 

When mulling over a purchase it's worth the effort to check out whether listed building consent has been sought for previous work. No record will indicate lack of consent. And this cannot be given retrospectively. Conservation departments may go so far as to allow that repairs have been made but it is always noted that that these were made without permission.

Thankfully, when buying a property, it is likely that your surveyor will be of great help where highlighting the incumbent issues inherent in the use of inappropriate products. One concern relating to cement mortar repointing will be the depth to which it has been applied. Deep might result in recommendations to leave it alone as damage to the masonry is likely should its removal be attempted.

Although you might be very confident at DIY, it's a very different state of affairs with a listed building. With modern builds a splash of paint or a quick repair might improve the property but once you start making changes to a period property then the results might substantially reduce its value. In many cases, using professionals from the smallest to the largest repair is often the best way.

I decided to have a ring round a few chartered surveyors to test a few hypotheses and was recently talking to Charles Brown from Cotswold surveyors (http://www.cotswoldsurveyors.co.uk/) who not only stated that contractors who understand traditional products are an absolute necessity but also employing the services of a specialist architect for large jobs was a prerequisite when making major changes to a listed building.

All surveyors are very observant and have trained for years to achieve their level of understanding of the way buildings work. Most are experts in the mechanics of older buildings and can spot an inappropriate repair a mile off. If you have not sought permission for one of these then it could result in potential buyers removing their offer. Hall and Ensom (http://www.hallandensom.co.uk/), for example, are another like minded company of surveyors who are happy to espouse the virtues of traditional products and the use of professionals on period homes. Speaking to them recently revealed that it can be helpful to have the input of the vendor during the survey as there'll often be questions about the products used for repair and refurbishment i.e. whether the paint which has been used is a porous clay, lime or chalk based product.

And even if everything appears in order, the path to period living can still be fraught with difficulty. For example, there are often issues with lenders such as banks and building societies. Although attitudes are slowly changing, for some reason a few believe that it would be unwise to supply funds unless there's evidence of a servicable damp course. Of course, as a listed building owner, the last thing you would want is one of these as they create more problems than they could ever solve. 

What could also trip up the selling process is a good solicitor. If experienced enough, he will be able to spot whether a potential seller is trying to pull the wool. For example, new laws of disclosure as from 2014 now state that a seller must provide information concerning work which has been done on a property especially if it will interfere with the future enjoyment the new owner expects from the house. I can see it now. "So Mr Jones, you've stated in your disclosure report that you've had no work done on your grade two listed property over the last ten years yet the estate agent's details state that this is a property which benefits from extensive recent updating. Did you apply for listed building consent? You didn't."

It could spell the end for the cost cutter, bodger and cowboy owner where listed properties are concerned because being one or employing a rogue could make a property unsaleable. The reason? Lenders will only lend if a potential buyer is able to get insurance against work undertaken that may have been done without listed building consent. If the survey highlights the possibility of such work then the buyer might not be able to move forward and you could end up having to reduce your price for cash only.

My main priority at this point is to try and advise you, coerce you, cajole and persuade you to only ever use natural materials during refurbishment and repair-work. Natural is always best when it comes to older properties as modern products tend to work against the house rather than with it. Using lime lime based products on listed buildings is always preferable. Not only from a personal health perspective but also from a legal one as the Conservation Department have powers to bring owners to the courts. And with very expensive outcomes. It’s certainly not unheard of for large fines to be imposed on those who’ve effected repairs without consent or have demolished parts of the building without permission. In the worst case the ultimate course of action (although extremely rare) is imprisonment or the confiscation of property. 


Should you choose to go down the route of employing contractors who are unused to working with traditional products then I can give you a hint as to what you may encounter. As a craftsman I've had the displeasure of working for owners and with tradesmen who are only too willing to apply cement and gypsum to properties. I've even asked them why. The answers usually reflect very little knowledge of the requirements of the local authority. They are simply unaware of the requirements of these bodies and are also unaware that products other than the ones used on modern buildings must be used on old houses. Most have less than a modicum of knowledge of the mechanics of older properties and their knowledge of their own products is limited.

If you do not instruct a plasterer to use lime then the result will be two coats of cement render and a couple of applications of multi-finish. You may be informed that the first two coats are breathable as they contain lime but what won't be mentioned is that it's hydrated lime which will be shovelled in alongside the cement. All you'll end up with is double waterproofing. It'll be finished with Multi or Board Finish and this is also non-breathable. The result will be that moisture will not pass through the wall and you'll get rising damp, problems with condensation and also the issue of salts rising to the surface of the plaster causing bubbling. 

Incidentally, there's a current trend for manufacturers of some cements based renders to refer to them as 'damp control'. All this means is that moisture will be stopped from evaporating away from the surface of the wall because the product will have waterproofed it.

So staying away from gypsum plaster and cement is always advisable as the upshot is that their use will almost certainly result in cracking due to seasonal changes and thermal movement. All newer products including Tarmac's Limelite have waterproofing qualities as well. Basically this stuff is exactly the same as a 6:1:1 cement render mix using Perlite to substitute some sand. Tarmac say it's a favourite of the conservationists. But try specifying it with the Conservation Department and see how far you get. 

But I digress. Back to gypsum: one of the eventual outcomes of using it might be that it will simply peel away from the surface of the wall should there be any moisture behind it. The reason for this is that gypsum comes in two forms: either mildly soluble or totally waterproof. In direct contrast, lime will allow moisture  to pass through it and simply wick it away. Although some contractors will say gypsum is porous, just because something holds water does not necessarily make it so.

As mentioned earlier, many contractors are simply unaware of the implications of working on period properties and most are certainly ignorant of the fact that they too can be prosecuted for undertaking inappropriate work on them when they’re listed. What you'll get from most plasterers is Unibond and render, or PVA and render, or PVA and British Gypsum's One Coat because that can look like lime when it's trowelled down. What you might even get is a light Multi Finish skim over your existing lime and that will be considered normal and good practice. 

If you'd like to do a bit more research then I've found a youtube clip on the use of gypsum versus lime mortar and also one on the virtues of using natural paints which you may find useful watching.

https://www.youtube.com/watch?v=iZlqzASDN_U

https://www.youtube.com/watch?v=4OgjftJ3kU8

There’s also the author Marianne Suhr who is an expert on older buildings and she’s written a number of books which are available online. However, should you require something more brief then there's always Period Living magazine which is out every month and costs only £3.70. It’s always good to familiarise yourself with as much as you can as forewarned is forearmed.

Correct aggregates for repointing where lime mortar is concerned

Firstly, let us take the ordinary and mundane subject of sand. As we all know, that which is used to lay bricks and stone is mostly sold from quarries and local builders’ merchants. It's called screened sand, soft, or building sand and is made to a particular recipe where different types of fines are combined with larger grains. But what if you want a soft sand for building or pointing with lime mortar? Can you throw a few bags in your boot and get going with a project? In short, the answer is yes, of course you can, but after reading this you might not consider it an option. The main reason for this is that building sand is too soft and this means the lifespan of your mortar will be reduced if you use it. Care must also be taken where colour choice is concerned as soft sand comes in a multitude of colours and if you or your contractor pick the wrong one then you’re in trouble.  You may even devalue your property.

At this point I need to be careful otherwise I’ll run the risk of revealing trade secrets so it’s probably best to keep this brief: for repointing with lime mortar you need a combination of two types of sand and both have to be washed. However, most trade and DIY outlets do not supply what's necessary. So if you use unwashed sand then impurities which have not been removed will rise to the surface of newly applied lime mortar.

Sharp sand, on the other hand, has very little influence on colour. But it will have a direct affect on texture and therefore finish. Ordinary sharp sand from a quarry or builders yard is a fairly uniform texture with aggregates large enough to make it qualify as sharp. In sum, it’ll do the job but it’s nothing special. It’s the type of aggregate which is perfect for laying patios or putting down a base for a shed. However, if you want sharp sand which is going to make the mortar in the joints of a period property look sublime then you need to extend your search beyond the average home improvement retailer. This is because when lime mortar is brushed, the larger particles of sand are brought to the surface and only a top quality purposely blended mix of sharp and soft sand will recreate the depth of shade and texture needed to replicate the highly desirable effect which is so enticing where beautifully maintained period properties are concerned.

I use what I consider to be the perfect blend of sand. It consists of a mixture of soft and sharp sand to the specifications which my experience dictates is correct. It looks superb, there’s no colour leaching and the aggregate sizes and colours go together to create the ideal tint which complements natural stone. Not only this, but it also conforms to BS EN 13139:2002 Aggregates for Mortar which is the current standard.

Secondly I wish to highligh the issue of exacting standards in the use of natural hydraulic lime (NHL), quicklime and lime putty as all are obviously a priority of mine. They're flexible and porous and need nothing added to them except the appropriate sand. But unlike many other contractors I do not adhere to the widespread practise of adding cement to make my mortar cure more quickly as this pollutes the mix and simply turns good quality lime mortar into plasticised cement mortar. This is the last thing any owner of a stone built property needs – specially one which is listed. 

And finally there’s the finish. Lime must be brush finished and should never be trowel finished. However, it takes time to dry sufficiently before any  brushing should take place. Brushing prematurely not only results in cracks but also in the appearance of what look like damp patches. They're not really damp patches, it's just that the brush forms the calcination coat and brushing too early creates a mottled effect in places. Although over time this does fade, it usually takes a couple of years. 

Furthermore, omitting any of the brushing stages - or brushing improperly - not only results in a poor finish, but any lapse also means that imperfections remain as these are never revealed and therefore never attended to. None of this may matter to a potential customer if price is the only issue but employing a contractor who fails to attend to mortar correctly during its drying stages results in a job which will not stand the test of time.

In sum, lime takes time and the process of lime mortar repointing is very labour intensive. Mess up on something as simple as wetting up joints before applying mortar and things start going downhill rapidly. Leave it too long before brushing and things look even worse.

Recently I was discussing the merits of lime after I’d removed a wall full of horrible grey cement mortar and mentioned the fact that you’ve got to fight with it to know it and only when you’ve fought with it for long enough will you be its master. But mastery is  not about thumping it into place and being boss. It's about the relationship you have with it and how you must allow it to be what it is and work with it  and not against it. The reason for this  is that it's a natural material and these need comprehending. If I were ever to use an analogy to describe it then I'd equate working with lime to training a dog. At some stage you realise that many of your ways aren't productive but you have to get to that point before a lifelong relationship forms.

Anyway, I hope what’s written above has been informative in some way and that you can now see at least some of the reasons why the Conservation Department requires an example square metre before allowing contractors loose on listed buildings. 

Thanks for reading.

If you would like further information concerning the use of lime mortar please see the ‘blogs links and articles’ page at michaeljamesdesign.co.uk