Ecological Proposed Enhancement and Development Plan (phlorum, 2022)

The development on Pelham Street has a statutory requirement under Section 40 of the Natural Environment and Rural Communities Act 2006 to deliver a project that offers a gain for biodiversity. The developers Geoffrey Osborne have chosen to meet these ecology requirements as part of an Ecological Design Strategy registered with Brighton & Hove City Council on 23 February 2022, as required to be outlined by Condition 39 of the original planning permission. Ecology simply refers to the study of the relationships between organisms and their environment.

In order to meet the statutory requirements of the developers, the Ecological Design Strategy addresses its ‘conservation objectives’ comprehensively throughout the project life cycle, from pre-demolition surveys to maintenance. Particular to note in the Strategy document is the special attention given to the potential of nesting birds and bats, species that would be affected during the demolition stage of the project. Demolition works were advised to take place between September and February to avoid conflict with the nesting season of gulls observed on site. A bat report was compiled in 2018 and although no evidence of roosting bats was found, it was also advised that operatives remain vigilant for the presence of bats during demolition.

The measures taken to improve the ecology of the site revolve mainly around landscaping. At the ground level trees, shrubs and climbers are to be planted along the boundaries of the site and at the edges of an inner courtyard included in the design. In the more open areas of the site grass will be planted with ‘scattered’ trees. At the upper storeys, communal space will have planters. A ‘green’ roof space is envisioned using flowering plants.

All in all, it is my opinion that the required statutory improvement to the ecology of the site will easily be met if the plans in the Ecological Design Strategy are successfully carried out. The site at Pelham Street pre-demolition consisted wholly of manmade hard surfaces lacking any sort of natural fauna, as outlined in the Strategy. Putting in greenery on site will ensure biodiversity value among the likes of birds and insect species, particular so within an urban centre typically lacking greenery such as Brighton. In this way I feel the project can enhance the local surrounding environment.

phlorum (2022) Proposed Enhancement and Design Plan. Available at: BH2022_00650-ECOLOGICAL_DESIGN_STRATEGY-18597657.pdf (brighton-hove.gov.uk) (Accessed: 15 May 2022).

phlorum (2022) Ecological Design Strategy. Available at: BH2022_00650-ECOLOGICAL_DESIGN_STRATEGY-18597657.pdf (brighton-hove.gov.uk) (Accessed: 15 May 2022).

Smith, Robert Leo and Pimm, Stuart L.. “ecology”. Encyclopaedia Britannica, 7 Feb. 2019. Available at: https://www.britannica.com/science/ecology (Accessed: 15 May 2022).

Details of the demolition of the old Greater Brighton Metropolitan College buildings can be found in the Demolition Environmental Management plan, submitted to Brighton & Hove City Council on 14 May 2021 to meet a planning requirement imposed under section 106 of the Town and Country Planning Act 1990. It is important to consider the potential negative effects that demolition can have on the surrounding local community, which is why the City Council probably have required this document as part of granting planning. The developer, Osborne, should act both environmentally and socially responsible during the demolition and throughout the period of works.

Demolition of the pre-existing buildings on site commenced in May 2021 and was completed in December 2021. Demolition was carried out by subcontractor Goody Demolition. During the demolition phase, potential dust pollution is at its greatest. Dust affects both the site and local area and can pose a serious harm to health. Different types of dust can be kicked up into the air: silica dust from ‘silica-containing’ materials such as concrete and mortar; wood dust; and other dusts from the likes of gypsum plasterboard     (Health and Safety Executive, 2020). All these would be present during the demolition on Pelham Street. To avoid dust becoming airborne, Goody dampened down ‘areas of demolition, stock piles and the crushing machine’ using a dust suppression unit (motofog multidirectional water spray).

The Demolition Environmental Management plan also outlines other risks to the environment that the demolition faced. To reduce carbon emissions, Osborne and Goody committed to using eco-cabins for site offices, using the most efficient plant machinery also fitted with catalytic converters, putting the site onto mains electricity as soon as possible. Fuel bowsers and plant were and are inspected daily. There is a ‘Pollution Incident Control Plan’ in place and plant nappies and drip trays are used to capture drips and spills from plant refuelling and maintenance. These measures are aimed at reducing ground and water pollution through contaminants such as oil.

Good Demolition & Osborne (2021) Demolition Environmental Management Plan. Available at: BH2020_00550-_DRAFT__DEMP-16212660.pdf (brighton-hove.gov.uk) (Accessed: 6 April 2022).

Health and Safety Executive (2020) Construction Dust. Available at: Construction dust (hse.gov.uk) (Accessed: 6 April 2022).

A retaining wall is defined as ‘a structure that retains any material and prevents it from sliding or eroding away’     (Jamal, 2017). On the Pelham Street development, 4 retaining walls will be used as according to the General Arrangement drawing.

The situation of retaining walls is shown in orange dashed line on the landscaping General Arrangement drawing (terra firma, 2020)

Although retaining walls can be constructed from a wide range of materials (including reinforced concrete, precast concrete, stone, etc.) the particular retaining walls to be built on this development are brick, as outlined on the General Arrangement. Details show that the level of Pelham Street will be higher than the level of the pavement at the frontside of Block A, which has necessitated the construction of a retaining wall along the boundary with the Street at the front of the Block.

Detail of retaining wall at frontside of Block A, at boundary with Pelham Street (terra firma, 2020)

Paving detail for boundary at frontside of Block A, showing footing foundation of retaining wall (terra firma, 2020)

The retaining wall detail drawing does not indicate any reinforcement to be made in the wall at the frontside of Block A. The wall can therefore be described as a ‘gravity’ retaining wall, where the weight of the brickwork itself provides the strength to retain the material. The retaining wall detail and the pavement detail both leave the exact construction of the brick upstand and its concrete footing to be described by the engineer’s specification. However, these are the general steps of the construction process of a typical stepped brick gravity retaining wall (the type which will be specified for use on this project):

(BRE, 1996)
(Structural Solutions, date unknown)
1. Excavate the soil material that the wall is to retain to allow for the retaining wall to be freestanding during its construction (whilst the brickwork bonds strengthen) and to avoid in-fall of soil material.

2. Excavate a trench along the length of the retaining wall to a minimum depth 450mm and width appropriate for the size of footing.

3. The footing should be set out in the trench with an appropriate concrete mix. The minimum depth of the footing is 300mm. The width of the footing should be 500mm for a retaining wall to maximum 825mm height; 650mm width for max. 1125mm height; 850mm width for max. 1425mm height; and 1100mm for max. 1725mm height. The top of the foundation footing should be 150mm deeper than the level of the surrounding soil.

5. The brickwork rising from the footing for the upstand of the wall should be position central to the foundation and stepped appropriately. To a max. height of 1725mm, the first 3 steps should be max. 300mm in height. The brickwork of the first step should have the width of 2.5 stretched bricks; the second step the width of 2 bricks; the third step the width of 1.5 bricks. A final fourth step can extend 825mm in height with the width of 1 stretched brick. This assumes the standard brick length of 215mm. Vertical movement joints should be provided in the brickwork at maximum 12mm centres, with 75mm diameter weep holes (PVC) additionally provided at maximum 1800mm centres.

6. A coping stone should be set at the top of the brick upstand, on top of a damp proof course layer.

7. The side of the wall retaining the material should then be lined with heavy duty polythene sheeting or painted with damp resistant paint.

8. 28 days should be allowed for the mortar joints to set in the brickwork. The damp proofing should be covered by fibre pads for protection during infill. To prevent water reaching the foundation footing, the same mix of concrete used in the footing should be infilled below the weep hole level. A drainage layer of minimum width 450mm against the wall should be infilled with clean gravel or crushed stone. The rest of the excavation should be filled with ‘lightly-compacted non-cohesive’ material.

There is no specific building regulations relating to freestanding retaining walls, but there is a general duty to ensure that any structure is safe.

Jamal, H. (2017) aboutCivil.com. Available at: Retaining Wall – Definition and Types of Retaining Walls | Gravity (aboutcivil.org) (Accessed: 6 April 2022).

terra firma Consultancy (2020) General Arrangement. Available at: T:\PROJECTS\2117 Residential Development, Pelham Street, Brighton\2117 PDF\2117 Stage 4\2117-TFC-XX-XX-DR-L-1002 General Arrang (brighton-hove.gov.uk) (Accessed: 6 April 2022).

terra firma Consultancy (2020) Details – Retaining Walls. Available at: T:\PROJECTS\2117 Residential Development, Pelham Street, Brighton\2117 PDF\2117 Stage 4\2117-TFC-XX-XX-DR-L-4102 Details – Reta (brighton-hove.gov.uk) (Accessed: 6 April 2022).

terra firma Consultancy (2020) Details – Surfacing 2 of 2. Available at: 4110 (brighton-hove.gov.uk) (Accessed: 6 April 2022).

Building Research Establishment (1996) CI/SfB (16.2) F (D): Building Brickwork or Blockwork Retaining Walls. Available at: GBG Retaining Walls Rev 16 (gov.gg) (Accessed: 6 April 2022).

Structural Solutions Ltd. (date unknown) Medium Height Brick Retaining Walls. Available at: retainingwall.pdf (structural.solutions) (Accessed: 6 April 2022).

Skip lorry at south gate of site (Fionnbharr McHale, 2022)

It is important to consider site access for the effective management of a project. Materials; plant machinery; prefabricated units for welfare and offices; skips; and operatives all have to be able to be transported to and from site. Poor access to site would mean that, for example, tipper lorries could not be loaded by excavators with material from excavations. This impedes works progress, incurring an increased cost.

It is noted in the demolition arrangement for the Pelham Street redevelopment that even a small skip lorry has an overall width of 2.39m and a turning radius of 6.34m     (Bright Plan, 2021). This makes site access to the project on Pelham Street challenging, with it being a narrow one-way street with parking spaces. Not only does this make it difficult for the number of large vehicles that will be used in the construction process to pass, it poses a safety hazard to vulnerable pedestrians on the pavement outside the site and other road users.

Demolition Arrangement Signage and Path Analysis (Bright Plan, 2021)

Traffic management is defined as ‘the act of directing vehicles and pedestrians around some form of disruption’      (TBF Traffic, 2022). Osborne have, in the case of this project, employed traffic management to close Pelham Street to vehicular traffic and redirected pedestrians from the pavement nearest on the north side of the Street. This has allowed for the needed access to the site, with lorries coming through the north gate at Cheapside and leaving through the south gate at Trafalgar Street. There is additionally plenty of space to allow for lorries to hold, if needed, on the closed street. This is evidenced via the photos of the site on this blog. The public do not come into contact with the vehicles accessing site, so the safety risk is reduced. Signs indicating that the road is closed, barriers and signs directing pedestrians are how traffic management is specifically deployed in this instance. During demolition, when there the number of lorries accessing the site is probably greatest in order to take away waste material, temporary traffic lights were installed on the junction with Cheapside     (Bright Plan, 2021).

Brighton & Hove City Council operate a traffic management permit scheme, under powers granted to the Council by Part 3 of the Traffic Management Act 2004     (Brighton & Hove City Council, 2022). This scheme has required Osborne to attain a permit from Brighton & Hove City Council for temporarily closing Pelham Street, a public highway, for the duration of works. The Temporary Traffic Regulation Order made by the Council closing Pelham Street currently expires on 27th October 2022     (The Argus, 2022).

McHale, F. (2022) Skip Lorry at South Gate of Site [Photograph].

Bright Plan (2021) Pelham Street Demolition Arrangement Signage and Swept Path Analysis. Available at: A1 (brighton-hove.gov.uk) (Accessed: 4 April 2022).

TBF Traffic (2022) What Is Traffic Management?. Available at: What Is Traffic Management? And How It Works in UK (2022) (tbftraffic.com) (Accessed: 4 April 2022).

Brighton & Hove City Council (2022) Traffic Management Permit Scheme. Available at: Traffic management permit scheme (brighton-hove.gov.uk) (Accessed: 4 April 2022).

The Argus (2022) Pelham Street – The Argus. Available at: Pelham Street – The Argus (Accessed: 4 April 2022).

Crane at north side of site (Fionnbharr McHale, 2022)

Crane at south side of site (Fionnbharr McHale, 2022)

Excavations on the Pelham Street site have been largely completed, in accordance with submitted sections of the large Block A building containing the apartment units. Section drawings show 2 separate ground floor levels: an upper ground floor in line with the existing level of Pelham Street, built up against the street; and a lower ground floor of Block A, which will be below the level of Pelham Street but at level with the rest of the site. I hope to expand on this particular aspect of the project in a later post.

There is steel on site to be used, according to fixing schedules, in reinforcing concrete to produce the required retaining walls of Block A at the lower ground floor level (as part of the concrete formwork). The wall of Block A retaining against Pelham Street alone will be in excess of 82m, clearly there is a substantial amount of steel to be fixed.

Considering the amount of steel to be fixed, the usage of static cranes can be justified. Steel is a heavy material that cannot be manually lifted around the site necessitating the aid of mechanical lifting methods. A mobile crane is typically a more cost effective method of lifting opposed to a static crane, saving on the labour costs involved in erecting the likes of the tower cranes seen on the Pelham Street project, which have to be assembled from its component parts. However, a tower crane (once erected) saves on the set-up time before lifts associated with their mobile counterparts. This is of benefit when there is a lot of lifting to be done: on this project, not only has the steel for this initial formwork to be lifted, but materials have to be additionally lifted for constructing the following 6 storeys of the large Block A alone.

The particular static cranes in use on site are tower cranes, the particular model a Wolff 180B. These tower cranes can have jib sizes of between 30m and 55m      (Wolffkran). Taking into account the position of the 2 cranes in relation to each other and the site, as well as my own visual observation, the length of the jibs of the cranes on site are most likely 40m      (Wolffkran). This length jib would provide suitable coverage of the site between the slewing of the 2 cranes. The maximum working load moment of each of these cranes is 3240 kNm, with a maximum safe mass of 8.6t lifted at 30m along the horizontal      (Wolffkran). Each base of the tower is 4.5m high, which gives the cranes a 28.9m height to top of the cabin. Access to this cabin, for the operator, is provided by a ladder up the length of the tower      (Wolffkran).

McHale, F. (2022) Pelham Street North Crane [Photograph].

McHale, F. (2022) Pelham Street South Crane [Photograph].

Wolffkran (Date unknown) Seite-1E. Available at: Seite-1E (wolffkran.com) (Accessed: 1 April 2022).

Former GBMC car park in site location (Frank le Duc, 2019)

Pelham Street is a quiet one-way back alley, running between Cheapside and Trafalgar Street, in the North Laine area of Brighton (just a 3-minute walk from St. Peter’s Church). The east side of Pelham Street has been formerly occupied by buildings of the Greater Brighton Metropolitan College (GBMC).

GBMC is undertaking an extensive scheme of modernisation works at its Central Campus, located on and in the vicinity of Pelham Street. As a result of this works scheme, GBMC’s older Victorian buildings on the east side of Pelham Street were made redundant. The sale of this property by GBMC was made to PGIM Real Estate, to secure part of the funding for the works at the campus.

PGIM Real Estate has partnered with Osborne Developments to deliver, on the site of the old College buildings, 135 new residential units. The units will consist of 1, 2 and 3 bed apartments and an additional 4 family town houses, with design undertaken by HNW Architects.  The apartments will be built within a 6-storey block. Planning permission was unanimously granted at full meeting of the City Council in 2019, with practical completion expected in 2023.

The proposed apartment block at Cheapside-Pelham Street (HNW Architects, 2021)

It will be interesting for me to track the progress of this project, undertaken by Osborne’s building division Osborne Construction acting as main contractor. The residential units are an entirely build-t0-rent scheme; none will be sold to prospective residents. Paul Stanford, head of PGIM Real Estate in the UK and Ireland, notes in his vision for the project the particular lack of suitable accommodation in the local vicinity—
         “The development is an important component in the regeneration of
          Brighton’s New England Quarter and will create a thriving
          community in the heart of the city, a sub-market that has suffered
          from a significant under-supply of high-quality rental
          accommodation over the years.”     (Paul Osborne, 2021)
I will reach out to Osborne Developments and Osborne Construction to find additional information about the project, possibly arrange a site visit.

In 2019 renting a 1 bed flat in Brighton was equivalent to paying a £170,207 mortgage, which would require an income 80% above the City average to meet (Brighton and Hove City Council, 2019). The need for additional supply of accommodation in the City is, in my opinion, dire based on this statistic. I look forward to seeing how the redevelopment of the east side of Pelham Street will juggle the challenges it will face in bringing the 135 new residential units to an otherwise unused brownfield site in prime location.

I will deliver content to this blog for the next couple of weeks covering a wide variety of topics related to the Pelham Street project.

Duc, F. (2019) ‘Work Starts on £21 Million Digital Centre for Brighton Students’, Brighton & Hove News, 2 August

HNW Architects (2021) Pelham Street Planning Approval!. Available at: Pelham Street Planning Approval! – HNW Architects (Accessed: 28 March 2022)

Osborne (2021) Osborne Working with PGIM Real Estate to Deliver Scheme in Central Brighton. Available at: https://www.osborne.co.uk/2021/06/02/osborne-working-with-pgim-real-estate-to-deliver-scheme-in-central-brighton/ (Accessed: 28 March 2022)

Brighton and Hove City Council (2019) Brighton & Hove Housing Market Report 2019 Q2 Apr-Jun. Available at: Microsoft Word – 2019 (2) Housing Market Report (Apr-Jun) (brighton-hove.gov.uk) (Accessed 28 March 2022)