Pete recently did an interview on BBC Radio 4 - You and Yours - which investigated a case history of failed cavity wall insulation.
We get a lot of questions about restrictions to what you can do or cannot do to a Grade 2 Listed Building. These also apply to Grade 2* Listed Buildings and Grade 1 Listed Buildings as well - there are some general principles that you need to understand first.
A Grade 2 Listed building is Listed because it shows some form of significance. Whether this is design, or because of a person living there, or because it is a good example of local vernacular architecture, is not really relevant - but significance is one of the main reasons it will be Listed. The Listing, which is easily found by doing a map search (sometimes using postcode or name / address will fail, because houses and properties change quite a bit over the years) so look on the map search and you'll find it - here: The List This will describe the building as it was Listed. It may not look like this, if it has been altered since - and any alterations need to be approved by your Local Authority (LA) Conservation department. Those changes are stored in the planning system, and you can search the planning records of your LA, to find any that relate to your building. The planning approvals or rejections will show detail of what was allowed.
Well - in theory, if you get permission, anything. It is getting permission that is the key.
What is 'doing'? The law states that a 'Material Change to a Listed Building' must be approved. So, a material change taken literally, means that if you remove a paint covering and replace it with a different colour, it's a 'material change'. If you take off lime render and put cement render on, it is a 'material change'. If you take off plaster internally, and re-plaster with gypsum, it is a 'material change'. If you change a reed thatch for a long straw thatch, it's a material change. In essence, if you change anything, either internally, or externally, you are doing something that needs permission and you are committing a criminal offence if you don't get approval from the LA conservation officer first.
There is a grey area: Repairs and Maintenance are excluded from needing permission. However - these are to be minor in nature - re-painting the kitchen walls, re-painting the windows in grey paint if they are already grey. Minor repairs to timber frames - removal of an area of rot for example, and a face repair made properly. Taking apart an entire gable timber frame and rebuilding it is NOT a repair, and needs conservation approval.
For the purposes of helping people understand the restrictions to working with Grade 2 listed buildings, or Grade 2* for that matter, you need to assume that anything other than very minor changes will require permission.
As an example, we recently had to help a client who had asked a builder to re-paint a timber frame. The builder cleaned all the flaky paint off the frame, found areas of rot, and brought in a carpenter to make repairs. A neighbour saw this and reported the client for illegal works. We were convinced the repairs were legal - the client was not making ANY changes, and the work was purely to repaint, and repair the frame. The LA conservation officer ruled that the work needed full Listed Building Consent, and we had to prepare a detailed schedule of repairs to each of the timbers, together with a specification of the jointing, the timber to be used, and the eventual finishes - together with a treatment of how we were to replace and repair the infil panels. So in this case, Grade 2 Listed Building restrictions turned out to be very onerous - and we feel unwarranted. However - the client got hte work done, it is legal, and the building has been correctly repaired.
So - there is a major problem with the rules - they are 'interpreted' differently by every Conservation Officer - some over zealous, and some not at all. There is a substantial problem with the system, and it is indeed unfair to a lot of Listed Building owners, and has undoubtedly cost building owners a lot of money and grief. My view is that it's better to ask before you do anything - get to know your local Conservation Officer - they dont bite - and most will be keen to help. Do remember though, they have no money, no resources, are financially presasured by their LA, many work part time. Personally I have a problem with a lot of them, because they are in the main Town Planners. They have little or no understanding of old buildings, or materials, and they are just pushing the law - so inevitably will demand a Listed Building Consent application - it generates income, creates work, and keeps them employed. There ARE LA's that don't work this way - by way of example, our Shropshire Council Conservation team is superb - and has a very active program of education and enlightenment for their Conservation staff. We work with them a lot, and always find them helpful and courteous.
We've also put some more information on our sister site - Heritage Survey which will give you a bit more information on technical aspects.