Judging Significance in the Historic Environment

The importance of Conservation Statements and Heritage Impact Assessments

Peter RawlingsCaroe Architecture Ltd

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TLIN

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LKThis talk

• who I am

• an introduction to CMPs and HIAs (the mechanics)

• a case study using No 1 Smithery, Chatham Historic Dockyard (with illustrations)

• lessons leant – what makes a good CMP?

PETER

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Who I am – an architect’s perspective

• Architect and Director of Caroe Architecture Ltd

• has commissioned, written CMPs and responded to other people’s CMPs over a period of 20 years

• with Inskip & Jenkins Architects – Battersea Power Station

• with vHH Architects – Corfield Court, Cambridge, Market Hall, Bolton, New Lodge, Windsor and No 1 Smithery – subject of the case study

• with Caroe Architecture Ltd – Nymans (with CAR), St Mary’s, Oxford

INTR

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NWhat is significance?

• Heritage has value and meaning – it enriches our lives

• Often quite complex – need to be teased out

• Dynamic and changing – a moment in time

• Value can range from local to international importance

• Statutory designations are helpful (listing, scheduled ancient monument etc)

• but there are places of local interest and group interest that may not be designated

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NHow is it judged?

Different types of significance can be identified (taken from EH Conservation Principles):

• Evidential – physical evidence of past human activity

• Historic – illustrative value and / or associative value

• Aesthetic – architectural and artistic merit

• Communal – social and/or symbolic meaning to the community

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NWhat is a conservation management plan?

• A formal and well established way of describing and revealing the significance of a site, building or place

• Briefer versions can be called Conservation Statements

• Allows us to identify where the value lies in an informed way – gives us a common understanding of the “heritage asset” to be conserved

• Forms a sound basis against which any proposals for change can be assessed

• Looks forward to future management

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NWhat is a heritage impact assessment?

• Usually forms part of a Design and Access Statement

• The “counterpart”: a formal response to a conservation management plan or statement

• Justifies each aspect of an architectural proposal against the guidance and policies set out in the CMP

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NWhat should a conservation management plan include?

• understand the site – gathering of knowledge

• assess significance – exploring the value of the parts and the whole

• assess vulnerability – conflicts, pressures, opportunities, risk

• set out policies that retain significance

• use a gazetteer for relevant information

• keep it simple, informative, clear and readable

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NWhat should a heritage impact assessment include?

• appreciate the value of the site, building , place

• explain the overall motivation for change

• assess impact overall (context, views)

• justify loss or adaptation to the fabric

• explain mitigation of loss

• demonstrate benefit of the design strategy

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NWhere can I find our more?

• Conservation Management Planning – Heritage Lottery Fund

• Conservation Principles – policies and guidance – English Heritage

• Planning Policy Statement 5 – Planning for the Historic Environment

• The Conservation Management Plan – James Semple Kerr

• Kate Clark – various publications for English Heritage

• Ask your local authority conservation officer

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YA case study: No 1 Smithery

Site: Chatham Historic Dockyard, Kent

Client: CHD Trust with NMM & IWM

CMP written by: CHDT

Project period: 2003 -2010

Design Team : vHH, PMT, MFP, P&M, Land, Appleyards

Funding: HLF, SEEDA, English Heritage

Awards: RIBA award (2011)

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YUnderstand the site

• desktop archaeological studies

• visual inspections and surveys

• intrusive inspections (trial pits, paint sampling, asbestos)

• historical primary and secondary sources

• discussion with community

• discussion with statutory authorities

• put into context (site has 100 listed buildings, 47 are Scheduled Ancient Monuments)

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YAssess the significance - designation

Historic Dockyard Conservation Area

Scheduled Ancient Monument

Grade 2 * listed

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YAssess the significance - summary

Occupying a central position at the heart of the Historic Dockyard the Smithery is an important metal working building with considerable local, regional and national significance.The Smithery played an important part in the mechanisation of the Royal Dockyards during the Napoleonic Wars and in the subsequent transition from the timber-hulled sail powered warship to the iron hulled steam powered warship. It has important associationswith people and ships, in particular Edward Holl, and HMSAchilles.Today the Smithery is one of only a small number of industrial scale metal working facilities to survive in Britain

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YPolicy – on change of use

No 1 Smithery is in a state of considerable decay and atrisk. Roof coverings failed during the last years of navalownership and the fabric of the building has sufferedaccordingly. Securing an appropriate new use withfunding for the building’s restoration together with asustainable long-term future for the building is one ofthe Trust’s highest priorities for the period of thisConservation Plan.

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YPolicy – archaeology summary

If any deep excavations are to be carried out, particularly in the area of the building founded on the chalk, it should be recognised that the potential for finding early remains exists.It is unlikely that any significant buried archaeology will have survived (from earlier phases of the dockyard) – although saw pits identified.Below ground structures related to the Smithery itself and its uses are definitely known to exist – identified from various trial pits and desktop studies.

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YOther policies

• approach to restoring fabric of walls and roof

• approach to adaptation and alterations

• an approach to fixtures and fittings

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YIntroducing the design brief

• restore the building and give it a viable and sustainable future, make it accessible and appreciable to the public

• provide a national museum standard touring exhibition space

• provide a permanent exhibition space telling the story of the dockyard and associated collections

• provide an accessible store for ship model collections from the National Maritime Museum

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YA heritage impact assessment

• looking at key policies

• how the proposals address the policies

• how the design strategy responds to conservation principles

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YPolicy – on adaptation & alteration

Policy 33.1 accepts that adaptation of the structure for anappropriate re-use is accepted and indeed is essential tosecuring the long-term future of this important structure.Whilst all such interventions should respect theSmithery’s history and significance it is also accepted thatsome compromise may be necessary in this respect.

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YGeneral design principles

• touching the existing building lightly (as possible)

• reversibility

• reuse of existing openings for circulation and services

• removal of fabric on an informed basis

• allowing the best of the building to speak

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YThe box within the box principle

• new structure independent to existing

• can meet stringent museum requirements with excess adaptation of existing building envelope

• forms a horse shoe of space around central courtyard – recalls first stage of building history

• volumetric character of large spaces not lost

• simple new finishes act as a foil to rich industrial patina

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YPolicy – on internal restoration

Internally significant issues will need to be addressed,particularly relating to contamination. The original dirtfloor is known to be contaminated with asbestos andpotentially other contaminants. Preservation of thepresent flooring material is therefore consideredimpracticable.

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YTreatment of floor - methodology

• soil samples for contamination

• trial holes to establish below ground structures

• test bore holes to establish ground conditions

• surveys to establish topography and critical heights

• flood risk assessment to establish base level

•Levels analysis to demonstrate loss of fabric

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YPolicy – on restoration

Restoration of the structure poses a number ofchallenges. Although the building is in an advanced stateof decay most of the elements remain in an identifiableform and are relatively ‘complete’. It is thereforethought that an appropriate restoration strategyshould be to return the building externally to the formfollowing the last major intervention – ie the period1943 – 1974. This strategy will however need to betested and if necessary modified during the designprocess.

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YTreatment of walls & roof - principles

• conditions survey of structure and fabric

• retain the patina of history wherever possible

• repair rather than replace where possible

• restore where elements lost

• strip back where unsafe – asbestos / projections

• re-use existing openings for circulation and services

• let new services show (but in a visually modest way)

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YPolicy – on fixtures & fittings

The Smithery contains a number of examples of fixedindustrial equipment such as small forges, wall cranesand bending slab/furnaces. These should be retained insitu where possible. Key items in this respect include thesmall forges dating from c 1860 adjacent to the west wallof Holl’s original building; wall mounted cranes aroundthe main Holl structure and the 1869 Slab shop. Should itnot prove feasible to retain other examples of forges andfixtures then appropriate record drawings andphotographs should be taken to document their position.If appropriate typographical examples of items notretained elsewhere in the building should be taken intothe Trust’s museum collections and stored elsewhere onsite.

surveys to establish topography and critical heights

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YTreatment of artefacts - principles

• identify and record

• retain selectively and generally without redecoration

• pipe bending floor cleaned and filled with sand

• hand forges retained in original position

• wall mounted cranes folded back against walls

• large wall brackets retained

• selective losses where inevitable and by agreement with English Heritage

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NLessons learnt

• Don’t forget to talk – dialogue is key

• CMPs and HIAs are tools only, but useful ones

• allow decisions to be made from an informed basis

• keep them relevant and informative

• specific but not too prescriptive

• don’t forget the bigger picture – a good design brief is just as important as a good CMP!