A Little bit about me...

I'm a Structural Engineer, specialising in conservation, at Hurst Peirce + Malcolm in London. I don't wear tweeds, am not particularly "cultured" and I'm not that old, but I do care passionately about the conservation of old buildings. I am a Chartered Structural Engineer, a member of The SPAB (formerly on the founding committee of the reborn Berks, Bucks & Oxon Regional Group), a Friend of SAVE Britain's Heritage and have recently completed a PD Diploma in conservation at West Dean College, with a view to achieving CARE accreditation. I hope to give you regular updates on my trials and tribulations as well as some insight into projects I am involved with and things I believe in.

Be patient with me - I'm no writer and I'm normally up to my eyeballs at work........

All views expressed here are my own.

Hurst Peirce + Malcolm, Celtic House, 33 John's Mews, Holborn, London WC1N 2QL

07854 624692 - richardsalmon9@gmail.com


Sunday, 29 August 2010

Engineering our built heritage - My way

ME:

I have always been fascinated by old buildings, both the way they were built and the way they have survived.

 
I didn't leave school wanting to be an engineer. I just wanted to draw stuff, so a bit of a fluke that I ended up starting as a junior draughtsman at an engineering practice that had a tie-in with the old PSA!

 
I was very lucky to have worked on some very important buildings early on in my career, with Morrish & Partners in London. The Natural History Museum, The Tower of London and The Palace of Westminster were particularly memorable projects, albeit with a fairly small scope of works in each case, but these and other similar historic buildings stayed with me as I gradually evolved into an engineer.

 
I think these early days really taught me to give old buildings the respect they deserve and I think that respect should be the start point for all those who work with our built heritage.

I had ten years off (working on new build alone with a different practice and to start a family) and came back to the world of conservation to find things had changed beyond recognition and so much for the better.

I believe good heritage engineers are a breed apart and will try to explain why.

Heritage Engineering:

The five “principles of conservation” that I follow are:

1. Conserve as found,
2. Minimum intervention,
3. Like for like repairs
4. Repairs should be reversible,
5. Repairs should be sympathetic.

(I know full well that sometimes these clash)

 
Heritage engineers have to temper their philosophy of conserving as found and of minimum intervention with their responsibility for the safety and structural integrity of the building and of its users.

The "Its stood there for x-hundred years" argument certainly carries some weight, but the engineer has to consider changes in the building's environment and usage. For instance, we know rainfall intensity is increasing, and our knowledge of wind loadings has advanced in recent years. Trees grow and die, and in clay soils, can have a dramatic impact on a building's foundation stability. Mining and other sources of subsidence also need to be considered. Different usages affect not only loads applied to the structure, but changes in the thermal effects that can also affect the fabric, not to mention the impact of modern M&E services.


 
I look at the following list of criteria to determine the suitability for any technique proposed for the consolidation of historic fabric:
  1. Is it "tried and tested"? Tried and tested techniques are preferable to new methods that may have an unforeseen detrimental effect on the building at some time in the future.
  2. Is the repair technique reversible? Can it be taken out at a later date without significant damage?
  3. Are the repairs really required or will the building survive without them?
  4. Does the proposed work improve the overall structural stability of the building?
  5. What damage will be caused if these repairs are carried out?  
  6. Will the repairs be seen?
  7. If they are seen, are they to blend in with the existing fabric or are they to contrast whilst still being in harmony?
  8. Will future historians be able to date the repairs?
  9. If there is a need to mix materials, what effects might this have?
  10. Will the building lose its inherent flexibility which enables it to cope with climatic changes without distress?
  11. Do the proposed methods meet the axioms "minimum intervention" and "conserve as found"?

Structural engineering for conservation is an art as well as a science. It takes little effort to design a major and intrusive scheme to deal with a perceived problem. It takes considerable expertise and experience to evolve a scheme that improves the condition of the structure which is unobtrusive and sympathetic to the historic fabric but which ensures that it has a sound future. It takes the same considerable skill to decide to do nothing.
 
It is essential for the engineer to accurately identify the source of the problem as many visible defects are merely symptoms of another problem, and not the problem in itself.

 
Experience and expertise are also needed to decide whether a building which is distorted actually has a current problem or if the distortion is a result of movements which took place a long time ago and which are not likely to recur.

 

It takes experience and an understanding of traditional buildings to carry out sympathetic repairs to historic fabric, not just an ability with numbers.
 
Water ingress, lack of maintenance and inappropriate previous repairs/alterations are the biggest causes of danger to old buildings. Control of these could mean that you will never need an engineer. 
 

I would like to think that the musings above will influence homeowners, developers and architects to select suitably experienced engineers for their projects.

2 comments:

  1. Very interesting, an insight into all the things you have to consider. I love visiting old buildings, recently went round Salisbury Cathedral and heard the story about how they added on the spire at a later date and the problems that caused. I liked your style, not too short and not too long, delivered clearly and concisely but not like a lecture. Good luck wiht the next one :-)

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  2. I guess it is naive to think that a building being there for hundreds of years means it is there for the next few hundred years too. Good job there are experts like you around to evaluate what is going on now.

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