Broomhills

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Download: 140910 Broomhills Appraisal Report
Project data
Project Reference Broomhills
Details Masterplan of new build residential neighbourhood at Broomhills.
Location Edinburgh
Use Type Housing
Client/Developer Barratt and David Wilson Homes
Lead Designers Ewan McIntyre Architects
Planning Authority Edinburgh City Council
Planning Ref Pre- PPP Application; PAN notice dated 4th October 2013
Issue Date 10/09/2014

1.00 Introduction

1.01 The site has been allocated for housing within the Proposed Local Development Plan [PLDP], site HSG 21, with estimated capacity for 425 -595 houses, the allocation maintained when a revised PLDP was approved at committee on 19 June 2014.

1.02 One of three important sites around Edinburgh, HSG 21 was nominated as a Locally Significant project by City of Edinburgh Council in order to receive the support of A&DS through Design Forum workshops. The council has high aspirations for the quality of development of the site. Given the sensitivity of greenbelt release the council consider that development must be carried out particularly well.

1.03 A multi-disciplinary project team have been instructed to prepare a Full Planning Application for development of the site by developer Barratt and David Wilson Homes. A PAN notice was served and a process of community consultation was carried out in parallel with the Design Forum Workshop Series.

2.00 Workshop Scope

2.01 The involvement of A&DS in the project was at the request of the council based on their current intentions [i.e. the council has provisionally accepted the principle, scale and type of development on this site through allocation in the proposed PLDP, albeit that the PLDP has yet to progress to adoption stage]. In this context neither this Appraisal nor the detailed comments and advice contained in it should be held as either promoting or questioning the principle, scale or type of development on the site.

2.02 A concluding workshop of the design forum series for Broomhills was held on 29th August 2014. This Project Appraisal provides the independent advice of A&DS in support of City of Edinburgh Council towards its pre-application consideration of the intended planning application. This will not form a consultee response to the intended planning application since the eventual proposals to be submitted with the planning application are likely to differ from the proposals reviewed and since A&DS are not a statutory consultee. Therefore the weight to be attached to this A&DS Project Appraisal will be a matter for City of Edinburgh Council.

2.03 The concluding workshop reviewed the design of the current development proposals including a review of the extent to which the current proposals respond to earlier workshop discussions with A&DS and other participants during a total of four Design Forum Workshops between 6th November 2013 and 29th August 2014.

2.04 Discussion topics established in advance of the workshop included:

  • A Landscape and Built Form in Context
  • B Detailing the landscape
  • C Built Form: street structure
  • D Built Form: street and house type detail
  • E Park
  • F Fitting in the School
  • G Burdiehouse Road Frontage
  • H Valley Route and SUDS strategy

2.05 An update on planning status was provided by council planning officers at the start of the workshop. The council had met the project team several times since the previous workshop to consider viewpoints for LVIA modelling, maintenance requirements for the park, the design of the mixed-use Burdiehouse Road frontage buildings and the design of the SUDS area.

2.06 The project team gave a detailed presentation of the current proposals, highlighting the way in which these have been developed in response to matters previously discussed during the Design Forum process. Key drawings presented are appended to this report.

3.00 Workshop Outcomes

3.01 Summary of Advice

A&DS has appreciated the positive and engaged approach of the project team and the City of Edinburgh Council officers throughout the design forum process, a process that has supported the establishment of design proposals linking landscape design, civil engineering, urban design and architecture to help meet the council’s policy objectives related to placemaking, street design and design quality.

In parallel with the design forum process the steps taken to consolidate ideas for this prominent and sensitive site, to carry out analysis and to rationalise the proposals have been welcomed. The panel recognised an increasingly place-led approach that is now influencing both the private and affordable housing proposed as well as the public parkland and green infrastructure design. The analysis and design re-evaluation carried out during the process has been productive and this has built up a much better understanding of the effect of design decisions for the local area and for new residents.

However, whilst this understanding has led to improved design in many areas the panel considered that the lessons learned from this process have yet to be fully embedded in the development proposals and therefore some further adjustment was sought to address aspects discussed at the concluding workshop. One further push would be very beneficial; to reconcile detailed layout and design issues with lessons learned and workshop discussions.

In this context the project is rated as Well Considered and Supported [Level 2], conditional on the outstanding issues raised in this appraisal being addressed. The outstanding issues are highlighted in italics in the text below.

3.02 Integrating New landscape and Built Form

The digital modelling of topography and views both into and out of the site, the emerging landscape and visual impact assessment [LVIA] work and the earlier sectional studies have been helpful in testing the effect of important design principles related to fitting new built form into the wider landscape setting. The panel welcomed the digital topographic modelling work although the full model was not presented. This has allowed the emerging and more precise three-dimensional evidence of relationships between site and proposals.

In terms of views out it has shown that key views towards Arthurs seat and the Pentlands can be appreciated and will be protected as seen from within the proposed public park. It has shown the planned framing, down open space corridors, of particular views into the surrounding landscape to the south and southwest.

In terms of views into the site it has shown the importance of tree planting and early planting establishment for mitigating impacts of key views towards the site and for breaking up the proposed massing of housing.
Nevertheless the panel retained some concerns and were not fully convinced that the proposals had been sufficiently developed to achieve the level of integration with the wider landscape sought at earlier workshops. In particular the treeplanting layering approach to mitigation, whilst supported in principle, is considered too insubstantial to be effective in its present form. Potential solutions were considered possible. The proposals could be supported if they are modified to resolve the following issues:

i The street trees along the primary street are intended as a key element in mitigating the impact of the visible housing at the upper part of the site. However whilst the choice of species [Tilia Greenspire] was supported the means of ensuring strong early establishment needs further consideration, including the timing of planting. The effectiveness of single lines of trees for mitigating impacts also needs further consideration.

ii The open green fingers, including the SE finger towards Burdiehouse Road, have the potential to provide more substantial blocks of tree structure at a mediating scale between the boundary structure planting and street trees, linking to the character of woodland in the wider open landscape, and helping to break up the perceived mass of housing.

iii There was extensive discussion about the design of the 10m mixed structure planting between the proposed SUDS pond and adjoining housing. This will be important in mitigating the visual impact on the key [modelled] view from Burdiehouse Road. This also has a role for the amenity of housing adjoining the electricity sub-station as discussed at earlier workshops. See further points in section 3.08 below.

iv A substantial landscape masterplan, fully integral with the streetscape masterplan, should set out the design intent in detail; linking to a woodland management plan that secures issues of establishment, longevity, maintenance and recreational management over time. This should secure the planned form at 5yrs and 10yrs as well as at maturity.

3.03 Detailing the Landscape

The simpler form and palette of landscape elements and the steps taken to integrate landscape elements with the built form along the green fingers and at private boundaries were all recognised as effective responses to discussions at earlier design forum workshops. One consequence of this is the now extensive reliance on hedges to form private boundaries. In taking the strategy for boundary treatment forwards the following points were discussed and the project team were urged to review the following aspects:

i Hedge treatment was considered to over-predominate and it was suggested that the 1500-1800h boundary wall treatment also proposed could be used more widely.

ii In terms of responsibilities for maintenance of the hedges and given the importance of these elements for street character and amenity, early establishment and a consistent regime of maintenance will be particularly important. Including these as part of a robust and effective factoring scheme was thought preferable to private maintenance by individual residents however it is recognised that there would be legal issues to resolve to achieve this in relation to ownership boundaries and title conditions.

It became evident during discussion that the handling of SUDS treatment and swales down the green fingers remained to be designed.
The panel considered that the swale design should be developed since it has great potential to add positively to the character of these spaces, including methods of forming dams to tackle the gradient. [Post meeting note: the project team are urged to look at examples of where this has been successfully achieved].

3.04 Built Form Points

The housing layout has become simpler, more legible, linking better to the relative handling of each character area and with fewer, better defined, character areas – all of which was welcomed. However there are several areas that were suggested should be developed further, towards the overall coherence previously discussed:

i The built edges to the spine road vary from having strong enclosure and a consistent frontage line, for example the terraced crescent frontage, to parts with varied set-backs that are more fragmentary – it was suggested that this might be reviewed to achieve a more consistent approach to the character of this principle street.

ii Continued consolidation and rationalisation of the block layout was also encouraged, particularly in considering the consequences for resident amenity of back-court parking. There remain several areas in the layout with back court parking and back gardens boundaries towards the public realm, which takes activity away from the main streets whilst making boundaries less attractive and more vulnerable. It was suggested that this could be tackled.

iii The layout of the rural edge housing was discussed once again, which is working better in the current illustrations. Further steps were encouraged with differing surfacing to strengthen the rural lane character whilst containing the impact of car parking.

iv Review was suggested of the element of the house frontage line immediately adjoining the proposed SUDS pond, to consider a set-back from the tree planting for better daylighting, compatible with set-backs used elsewhere along the edge housing, for the benefit of residents amenity.

The intention to use standard house types and the council’s assent to this is acknowledged. The benefit of the way in which the standard house types have been composed in the layout, forming streets and places, has the potential to create an attractive and coherent streetscape. The restrained palette of cladding materials and colours was also broadly accepted. However it was suggested that further steps should be taken to align the house types with the placemaking intent including:

i To adapt the catalogue house type elevations such that they are ‘special’ to the site. This might be through simplification of the house type detailing and language of components such that they appear less ornate and without elaborations such as overhanging eaves, hipped roofs, bay windows and stone quoins towards simpler forms compatible with local character. And such an approach should link to the subdivision of the masterplan into the now relatively few character areas – creating a locally established architectural language.

ii The panel noted a disparity between the compositional language of the mixed use gateway buildings at Burdiehouse Road, with its projecting vertical corner elements for example, and the architecture of the house types beyond. The panel suggested that these differing architectural languages could be better aligned with one another, through changes to both houses and gateway buildings.

The range of street paving materials currently proposed and an approach led by Designing Streets principles were strongly supported including the use of block paving; permeable paving as part of the SUDs strategy; material changes at nodes, junctions and crossings; and the use of blacktop limited to parts of the primary street.

Further discussions were required with the council in respect of the anticipated broader range of adoptable materials aligning with the new CEC Street Design Guidance.

3.05 Park

The core role and value of the park as a central defining space for the new community, and the way both houses and school are composed to strengthen its function have been discussed in some depth in earlier workshops. The panel welcome this process which has established this core role of the park, it’s interrelationship with the new housing, as well as the park’s visual and physical linkage to the wider landscape. Views from the park and the way house frontages are handled at park edges are generally a big improvement in the developed proposals. The panel recognised the more convincing handling of routes through the park as a response to the topography. However:

i They urged further development and full exposure of the proposed contour re-modelling to inform a tree planting structure better related to the retained and new contours and topography.

ii Given the exposed location of the park and the reliance on tree structure as part of the mitigation strategy for landscape and visual impacts the panel advised further consideration to resolve tree species and structure that is robust enough to establish in these conditions (concerns over Sorbus Aria, for example).

iii It was also suggested that groupings and blocks of trees would generally be more likely to be successful than single lines of trees. And it was suggested that a simplified and naturalised use of tree planting around the park edges would be more consistent with the broader landscape strategy of integration with the characteristics of wooded areas in the elevated topographies of the wider landscape.

3.06 Fitting in the School

The location and siting of the school were discussed and the principles acknowledged at earlier workshops. The development of the school brief are a matter for the council and were not considered by the panel. Whilst our earlier advice has influenced the masterplanning there are some matters discussed at earlier workshops that will remain important for the school design when this is developed.

It was suggested that the integration of the school into the neighbourhood should be considered further in three respects (1) to create a foreground garden/threshold for arrival in the sheltered part of the park] (2) to retain the main school frontage towards the central community park and (3) to strengthen the planned urban walking routes to the school from Frogston Road East and Burdiehouse Road.

3.07 Burdiehouse Road Frontage

The panel welcomes the development of the frontage buildings to form an urban gateway and a local centre, including the provision of informal frontage parking, the creation of a public space, and the allowance for ground floor office and retail units with apartments above. The use of street trees and street furniture were also particularly welcomed here at this social hub.

i It was agreed that bolder handling of the public space proposed was achievable to signal pedestrian priority across the public space and carriageway such as united paving and a break in blacktop roadway.

ii Equally more could be done to change the character of the immediate part of Burdiehouse Road. As currently proposed wide radius kerbs, offset crossing points, and level changes at the verge to Burdiehouse Road all serve to create conflicts with pedestrian desire lines across Burdiehouse Road and into the site. Further design work was encouraged to develop the junction and crossing design, to form a more substantial and attractive pedestrian crossing of Burdiehouse Road and to take full benefit from the potential of Designing Streets policy.

iii There was discussion about the amenity and experience of residents of both upper floor apartments and of ground floor apartments in adjoining blocks, since these will be affected by parking and service arrangements both in front of and behind the buildings. The amenity of residents entrances and defensible space at ground level need particular attention. This element of the layout might change in any case as part of the broader approach of designing-out back- court parking, as referred to at 3.04 above.

3.08 Valley Route and SUDS strategy

In respect of the valley walking route and perimeter green corridor:
In developing the means of handling the edge housing and the intended rural lane character it was felt that sufficient space should also be given to allow for the future growth of existing and proposed trees. Further attention should be given to this establishment process and to the management of the perimeter woodland edge for recreational use, including planning for changing character over time. A suitable strategy needs to be incorporated in the woodland management plan.

Suitable lighting needs to be considered for this lane and edge as distinct from the lighting of other residential streets e.g. low level lighting to ensure an appropriate softer character for this woodland edge.

In respect of the SUDS pond area the development of the landscape and SUDS design in this area was recognised however the panel urged the team to further develop the proposals to address key issues including:

i Ensuring that the specification of this planting will provide strong enough tree structure in terms of the LVIA.

ii Re-checking whether trees can be introduced adjoining the substation in the 1:200 year flood zone, since this would be preferable.

iii Reviewing the shape/ width of the east corner of this belt which could form a smother transition to the proposed ‘green finger’.

Housing Typology Case Studies

These examples illustrate where architects and urban designers have reconciled functions of the individual house that are integral to placemaking.

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