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One of the things that sets our cities in the UK apart, and London in particular, is that the heritage and culture has been incredibly well preserved in our streets. The history of buildings and the people who lived in them is fascinating (as many of my colleagues would attest, I love researching the existing buildings that I work on!) and there are parts of London where you really feel like you have stepped back in time.

As we redevelop more and more, the listed building process is one of the best tools we have for protecting those assets, and in theory it is the best of both worlds: we can retain and protect a historic building while continuing to use it.

But there is a fine line between retaining buildings and creating a city full of perfectly preserved but unusable buildings. And if that building cannot be modified to work for modern uses, what then?

In the middle of a climate emergency鈥� maybe we have to reconsider the balance between remembering the past and being useful in the future

Listed buildings are trapped somewhere in the twilight zone between the period in which they were built and the modern day: a record of the way we used to do things, but often not quite suitable for their intended present-day use. Staircases are probably not wide enough to be used for escape, fire ratings can rarely be met and structural capacity may be significantly lower.

In the middle of a climate emergency, when we are trying to minimise our impact on the environment, reduce the materials we are using and re-use buildings as much as possible, maybe we have to reconsider the balance between remembering the past and being useful in the future, even if that鈥檚 a little bit more painful for those of us who love the history!

The re-use of floor joists is a great example of this battle in terms of structural engineering. Floor joists in most older buildings are difficult to justify to modern standards 鈥� even if they are in good condition, we almost never know the timber grade and therefore make a conservative assumption about its strength.

In many buildings the floor joists are timbers that were re-used from other buildings, or in some cases entirely different structures, such as boats. But if the building is listed and the joists are considered part of the listed fabric, then we have to retain them, even if they are damaged or significantly below the strength they should be.

In many cases we are not even allowed to touch them, which means we cannot strengthen them. So instead we have to insert additional structure alongside or at a different level in order to re-support the floors.

But perhaps instead of just retaining the fabric, the way you might preserve a pot in a museum, we could also consider the philosophy with which the buildings were constructed. If a thrifty builder of the past could find a way to re-use ships timbers in the building, couldn鈥檛 we re-use those timbers elsewhere in the structure, where they can be used effectively?

Wouldn鈥檛 this be a better continuation of the building鈥檚 story than creating a hybrid of redundant old structure and new working structure?

If we can make changes that also benefit the climate, such as installing solar panels where they cannot be seen, isn鈥檛 that a compromise we can live with?

Clearly there are some buildings where it would be unthinkable to modify them either internally or externally but, for most listed buildings, design decisions are a compromise between new and old, and if they cannot be adapted they run the risk of being lost altogether.

Renovating buildings such as the Palace of Westminster is a huge challenge but is vitally important for their preservation; without proper fire compartmentalisation even a small fire could lead to catastrophic damage. Plus, if we can make changes that also benefit the climate, such as installing solar panels where they cannot be seen, isn鈥檛 that a compromise we can live with?

The things that we need from our buildings are not the same as they once were and, for me at least, the stories of the people who lived there and the way they used the building is just as important as the fabric itself.

Listed buildings will help us to remember those stories and ensure our beautiful streets are not destroyed. But they have to be able to change and evolve if they are going to remain useable in the living, breathing cities that we all know and love.

Anna Beckett is an associate at Webb Yates Engineers. She writes regularly for