Obtain the correct permission
It can actually be a criminal offence to alter a listed building without the correct consent in place, so it is vital to make sure any alterations you make have been given the correct approval in plenty of time. Listings can sometimes extend as far as internal fixtures and fittings so make sure you know exactly what you do and don't need to have permission for. The best bet is to err on the side of caution and get any changes that you are considering approved with listed building consent. It will avoid a big headache in the future!
Check that you are insured
As the owner of a listed building, it is particularly important that you ensure you have a suitable specialist home insurance policy in place to repair any unforeseen damage that could befall your property. You are legally obliged to maintain the property in a good state of repair, so if there was a huge incident such as a fire, you could be left with a hefty bill if you haven't taken out insurance.
However, there can sometimes be difficulty in obtaining a suitable policy in the first place. Lots of standard providers will be unable to cover listed buildings, particularly since their rebuild costs are often significantly higher than an equivalent new build. Luckily there are a number of specialist listed building insurance providers who are able to cover such properties, even when they are undergoing renovations.
Keep your alterations sympathetic
There are two main schools of thought when it comes to making alterations to listed buildings. One school of thought believes that extensions should be as in keeping with the original building as possible, so that the historical look is maintained. Others believe that extensions should be notably different to the original structure in order to easily establish what is old and what is new. Whatever thoughts you share, it is vital to ensure that you use suitable materials in the upkeep and alteration of your listed building (both for aesthetic reasons and to make sure you keep the planners happy!) Wooden windows and doors should always be used and wherever possible traditional building materials and techniques should be utilised.