If you are thinking about buying an old building for the first time, the chances are the appeal and charm of the property will carry you away. The sheer pleasure of potentially owning something so special may on its own drive you on to buy unwarily. But beware, don’t get carried a way by the appeal of somewhere special until you have unlocked some of the responsibilities about it’s care

Special-to-you properties are often bought on something as fragile as a whim or a dream. On the whole people are careful enough and financially astute (or robust) enough to deal with problems that may arise and many deliberately don’t have a full survey carried out for fear of tarnishing the 'dream' process – or worse – finding that they really shouldn't buy.

But old properties, semi-ancient buildings shall we say, are different. At some point they will need repair and it’s so easy to rip out the special character of a house with unfortunate and unsympathetic renovation. The building can easily be ruined, its special character obliterated or swept away by the ill-advised and hasty actions of new purchasers.

These mistakes usually arise because of ignorance rather than malevolence towards historic buildings. The fault may be laid at the feet of professional advisers, builders, owners, or all three.

The Society for the Protection of Ancient Buildings (SPAB) have produced a leaflet that can help you with that ‘leap into unknown territory of old building care.

Founded by William Morris in 1877 to counteract the highly destructive 'restoration' of medieval buildings being practised by many Victorian architects, the society today it is the largest, oldest and most technically expert national pressure group fighting to save old buildings from decay, demolition and damage.

The society is there to advise and educate. It also campaigns. It represents the practical and positive side of conservation and has a firm set of principles about how old buildings should be repaired and the practical knowledge to show how these can be put into effect.

In the excitement of the chase after a particular dream property you could miss a few pointers – these then are a few ideas from SPAB you may not have considered.

Is this building the right one for you? It may have magical qualities, but they may be distracting you from reality. Take a moment to consider what you need in a property.

If your preference is for vast, uncluttered spaces, don't purchase a cramped cottage and then attempt to turn it into a double height hall, or vice versa. Countless converted churches, schools and barns around the country are proof that standard domestic living areas rarely sit well in a building that once offered soaring space.

Don't just love a building’s eccentricity. You’ll be living with it and should be prepared to accept its particular character, its quirks, even its warts. It is essential that you adapt to it, rather than trying to iron it into shape according to a completely different model.

There was no standardisation in old buildings; they followed the logic of their location, the dictates of materials and the skills of the period. If you make those undulating plaster walls around the house plumb-straight, with every corner razor-sharp, your cob cottage will have disappeared. You will have thrown the baby out with the bathwater.

In an unaltered property, the door and windows will follow the proportions of the building as a whole. Replacement doors and windows, especially those easily bought off-the-shelf, have no such sympathetic relationship to the building.

Even if you do not plan to repair or renovate immediately, the building will soon need tender love and care. Understanding that specialist care will be required before you buy could save heartache for you as well as mutilation of the building’s character.

It may well be that the surveyor you used had little specialist experience of historic buildings, particularly a surveyor used by a mortgage company. Problems of liability mean that a surveyor is likely to draw attention to all apparent defects. Remember that by no means all the points raised in a surveyor's report will be a cause for concern or will require immediate action.

If you are concerned at an early stage then ask for a surveyor familiar with Section GNA 2 of the RICS Appraisal and Valuation Manual.

Before you start any renovation seek professional advice at the earliest possible moment. Try to find someone who is a specialist on old buildings of this type and period, and ask to look at other work they have done. The specialist could be an architect or a chartered surveyor; it is their expertise and attitude to the building that is the issue.

The same applies to your choice of builder, or the firm nominated for the job. Ensure that you have found the best people for the job. It may take time.

• Get to know the property thoroughly, find out everything you can about it.
• Explore cupboards, roof spaces, cellar.

Take time to understand the property, to discover how it was built, why the rooms have that kink, why that wall is extra thick. You will find evidence of previous repairs and alterations and maybe find that they were not dealt with properly.

Move slowly and get to know the property inside out. The more you know about your own building, the better client you will be, the easier it will be to brief a professional adviser or to work with a builder.

Don't start ripping out the building on day one - what may appear to be worthless may in fact be important. The essential fabric should be worked on first, no mater how mundane it may seem.

Once the fabric is sound you can begin on the enjoyable things, the mod cons and decoration. Do ensure that the interior features are covered up though – before you let the builder loose inside. Even the most conscientious can have an accident.

Fashions come and go but try to respect the past. Avoid guesswork and conjectural restoration. Work with what you have – after all, that was what drew you to the building in the first place!

When you have to add to the building or do new work in the interior, don't ape the existing. Try to find someone who can understand the character and qualities of the old but can add their own contribution, respecting the proportions and form of the building. The new work should be honestly of its time, our own time.

Avoid experimental materials and stay with the tried and tested. Remember, the old, traditional materials and finishes were textured, rather that highly finished, porous not impervious. By using the wrong material, employing a ham-fisted builder or an arrogant professional you can blot out the character, age and charm of an historic building in a matter of hours.

In recent years there has been a revival in many traditional materials and finishes; keeping the character of your house is easier now than it was twenty or thirty years ago.

In the long-term, the old adage is to do little, and often, to keep an old building in good condition. That is the best approach, from the very beginning.

The ‘Look Before You Leap’ leaflet should be available at most Local Authority Planning Departments and Estate Agents. It’s also available on the society’s web site www.spab.org.uk

The Society for the Protection of Ancient Buildings is a charity and members carry out most of their work voluntarily and enthusiastically. Many are experts in their field.

The society’s technical staff answers hundreds of enquiries on every aspect of repairing old buildings. While promoting the use of traditional materials and skills the society keeps up with current technical issues, regulations and materials which may have both positive and negative implications when applied to old buildings.

Events are run for members including lectures and visits to historic towns and buildings not generally open to the public.