What it is really like to work on a listed building

People come to us with two opposite misconceptions about listed buildings. The first is that nothing can be changed. The second is that as long as you do not touch the outside, nobody minds. Both cause expensive problems.

What listing actually means is that the building, in its entirety, is on the national list of buildings of special architectural or historic interest, and that consent is required for any works that would affect its character as a building of that interest. Inside and outside. Fixtures as well as fabric. Later additions as well as original ones, because a listing covers the building as it now stands.

What needs consent, in practice

There is no published list, which is the thing people find hardest. The test is whether the work affects character, and that is a judgement made by the conservation officer at your local planning authority.

In our experience, on interiors, the things that reliably need consent are: removing or altering any historic joinery, panelling, doors or staircases; changing plaster type on solid walls; opening up or blocking fireplaces; altering room layouts by removing or adding partitions; anything fixed into historic structural timber; and replacing floors.

Things that usually do not: redecoration in like for like materials, moving free standing furniture, and repairs on a genuine like for like basis. Even here, if the existing finish is historically significant, painting it can require consent.

The honest answer is that you ask. Most conservation officers will give an informal view by email on a clear question with photographs, usually within a few weeks, and that email is worth having. Doing work that needed consent is a criminal offence rather than a planning breach, and it does not go away when the house is sold.

What an application involves

A listed building consent application needs drawings of what exists and what is proposed, a heritage statement setting out the significance of the building and the impact of the works, and photographs. There is no application fee, which surprises people who are used to planning fees, but the preparation cost is real.

For the living room in a listed farmhouse, our drawings and heritage statement came to £1,400. The determination period is eight weeks in principle. Ours took just over four months, which is not unusual, and the delay was not obstruction, it was a conservation officer covering a large district.

Plan for it. If you want a room finished by Christmas and you are starting the consent application in September, you are not going to be finished by Christmas. On our own programmes we treat consent as a phase with a start and an end, not as a piece of paperwork that runs alongside the design.

The two mistakes

The first is gypsum plaster. It is the most common damaging thing done to old buildings and it is done with the best intentions, usually as part of a modernisation in the seventies or eighties. A solid stone or brick wall with no cavity and no damp proof course manages moisture by letting it move through the wall and evaporate. Gypsum plaster and modern masonry paint stop that happening, moisture is held against the wall, and the bottom of the wall goes damp.

The damp is then diagnosed as rising damp and treated with an injected chemical course, which does nothing to a wall that was never rising in the first place, and then a waterproof render is applied over it, which makes it worse. We have seen that sequence more than once in the same house.

The fix is to take the gypsum off and put lime back. It is slow, skilled and expensive. In the farmhouse the lime plastering alone was £8,400. It is also the thing that solved the problem without an injection, a membrane or a new skirting.

The second mistake is assuming the previous owner had permission. If a room was altered in 1998 without consent, that is your problem now, not theirs. Before buying, ask for the consents. If there are none for obvious changes, factor in the possibility of having to apply retrospectively or undo the work.

Working with the conservation officer rather than around them

The single most useful thing we do on a listed project is meet the conservation officer on site early, before the drawings are finished. It costs nothing, it takes a morning, and it turns a series of guesses into a conversation.

Officers are usually more flexible than people expect about modern interventions that are clearly modern and clearly reversible, and much less flexible about pastiche. A plainly contemporary insertion that can be removed in fifty years leaving the fabric intact will often be accepted where a fake period feature will not.

They are also, and this matters, the source of information about the building. On the farmhouse the officer told us there was likely to be a bread oven behind the blocked section of the fireplace. There was.

What we would tell anyone starting

Get the informal view in writing before you spend money on design. Budget for lime, and for the time lime needs to cure. Assume the consent will take three to four months rather than eight weeks. Do not remove anything before you know what is behind it, and do not open anything up without asking whether the opening up itself needs consent.

And keep a record. Photographs before, during and after, plus a note of what was found. It costs nothing, it is genuinely interesting, and it is the thing the next owner and the next conservation officer will thank you for.