Well done EH and all concerned | Forum

Silbury Hill 180

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Silbury's structural integrity

fitzcoraldo Dec 29, 2007 21:32:31

Replying to jimit

"However, EH were implacably opposed to grouting and I don't know if this sort of option was ever discussed with Skansia.
Ain't hindsight wonderful!"

Hi Jim
The answer to your question and reasons for not using the drill and fill method are set out in the 2005 Conservation Risk Assessment, freely available on the EH website ( http://www.english-heritage.org.uk/upload/pdf/Risk_assessment052005.pdf) along with a host of other documents. I'm not sure if they discussed it with Skanska but they did manage to employ the expertise of folk such as Emeritus Professor Richard J. Chandler of Imperial College, Fellow of the Royal Academy of Engineering and M. H. Worthington of the Dept of Earth Sciences at Oxford.

As for the poly bags. This fix is supposed to be a permanent fix therefore requiring stability and longevity of materials. Using a natural fibre would surely run the risk of biodegradation before the materials have had a chance to stabilise properly thus running the risk of further collapse. Surely the main aim of the project is to fix the hill permanently and if modern materials are the best for the job then so be it.

I guess I'm setting myself up here to be knocked down but I'm fed up of this constant nit-picking, heresay and rumour. I have tried to keep away from the debates because there seem to be a few here who are working on an agenda that involves constantly beating EH with a big stick for doing exactly what they have been asked to do. I guess I may be in a minority here but I have followed this project with great interest and actually think EH have released an unpresedented amount of freely available material to the public, they have also involved local people and national organisations with an interest in the hill. It's very easy to sit on the side lines and snipe at EH but please show me a project that has done more to keep the public informed.
I would like to congratulate all the folk involved on doing a great job, it looks like the goal of permanent fixing of the hill is in sight and it has been done safely and efficiently.
Well done EH.

cheers
fitz

Littlestone Dec 29, 2007 21:38:54

Replying to fitzcoraldo

Nice post fitz - don't agree with you but respect your calm and alternative counter argument(s). This issue looks like it will run a little more and be discussed here in the days to come in considerably more detail.

Cheers.

LS x

Littlestone Dec 30, 2007 11:35:15

Replying to fitzcoraldo

Morning fitz. You raised some interesting points last night, one of which I'd now like to address -

It is reasonable to say that, "...the main aim of the project is to fix the hill permanently and if modern materials are the best for the job then so be it." but there are a couple of problems there: the first is that modern materials are not always the best solution simply because they have not been tested over an extended period (and in the case of Silbury we're probably talking thousands of years in a unique environment). We don't really know how the plastic is going to react with the interior of the structure.

There's a principle in conservation that says as far as possible the same (or as near as possible the same) materials should be used for conservation as the original is made from. Sadly, the annals of conservation are littered with examples of well-meaning conservators/restorers using a new, seemingly stable material, only to discover a few years later that the new material is incompatible with the original. The second objection to both plastic, or bags made of a natural fibre, is that both are likely to leave large, alien deposits within the structure - that cannot be ethical on archaeological, conservation or religious grounds.

It's been suggested elsewhere that chalk blocks could have been used for the dividing walls. I don't know if there are good reasons why that method wasn't used but it would have seemed to have been the ideal way of solving the problem. After all, these dividing walls (unless I'm missing something) are only being put in place so that the areas behind them can be properly backfilled - they are not load-bearing as such.

jimit Dec 30, 2007 11:35:39

Replying to fitzcoraldo

Thanks for your measured reply Fitz. I for one have no intention of joining any slanging match here or elsewhere.
Re the poly bags... I am sort of coming round to your point of view...natural materials would degrade and migrate and contaminate other sensitive remains but they still grate nonetheless.
When Fachna McAvoy wrote the article (May 2005) you quote, the excavations had not started and the conclusions as to the state of the interior of Silbury were of course speculative. EH cannot be blamed for going ahead on the recommendations of their experts.
Once inside, however, I'm sure they were shocked at the state of the tunnels and voids, the twisted Atkinson arches, the continuing collapses and the dangers of working there. I'm sure there have been many ad hoc decisions made as the excavations continued and when the final report is published it will make fascinating reading. With hindsight will they say "If we knew then........We would have done it differently"?
IMHO the updates have been rather terse and has anyone got any answers from "Ask the experts"?
If anyone out there has reliable info from the horse's mouth as it were, surely it is in the public interest to post it here so that fruitless speculation can be ended and a sober and adult debate continued. All everyone wants is the best possible preservation for Silbury that the early 21stC is capable of. We criticise heavily previous excavations, let's make sure that future generations do not say the same about us.
Jim.