National Urban Design Conference

Transcription

1 National Urban Design Conference Refurbishing Housing to meet C21st needs Friday 9 th October 2015 James Traynor Image(s) z 1

2 Doing retrofit properly achieving EnerPHit at scale. What are challenges? 2

3 Doing retrofit properly achieving EnerPHit at scale. What are challenges? 1. Technical EuroPHit study (BRE/ PHI) 3

4 Doing retrofit properly achieving EnerPHit at scale. What are challenges? 1. Technical 2. Human LSE Report 4

5 Doing retrofit properly achieving EnerPHit at scale. What are challenges? 1. Technical 2. Human 3. Financial ECD Study 5

6 1. Introduction 2. Capital Cost Differential models 3. Lifecycle cost analysis 4. Other reasons 6

7 1. Introduction 7

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32 Wilmcote House 32

33 Wilmcote House External walkways Living room and door to balcony Open balcony 33

34 Works: Envelope New steel structure Proposed new external wall Existing wall of living room and open balcony Maisonettes Bedroom Living room Balcony Bedroom Kitchen/Dining Walkways Flats 34

35 Works: Envelope Existing envelope: Proposed envelope (preferred option): Schematic of the maisonette form pre and post-retrofit (Access deck on the South-East elevation) Teli, D. et al., Impact of current occupant behaviour on potential carbon savings in a council owned tower block undergoing retrofit. University of Southampton,

36 Works: Existing envelope 36

37 Works: Envelope Enclosed walkways Enlarged enclosed sun-space Enlarged living room 37

38 Works: Windows 38

39 Works: Roof 39

40 Works: Maisonettes Bedroom Bedroom Bedroom Bathroom HWC W C MVH R Kitchen / Dining Living room Walkways / access deck Sunspace Extended 7m 2 Existing wall of living room and open balcony Proposed new external wall Lower level Upper level 40

41 Pilot maisonette: MVHR in existing cupboard Existing cupboard in entrance hall Paul Focus 200 installed and running 41

42 Pilot maisonette: MVHR system Supply valve in bedroom and ducts in existing riser Temporary exhaust and intake valves to corridor. After enclosing the walkways these will be extended to the external wall 42

43 Pilot maisonette: bulkheads for ducts New entrance door and lowered ceiling for exhaust and intake ducting Ducts boxed-out in a bedroom to connect them to the riser 43

44 Pilot maisonette: M&E New storage heater in bedroom New insulated hot water cylinder 44

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50 2. Capital Cost Differential Models Passivhaus specification (as tendered) Building regulations equivalent (Part L 2010)

51 Overcladding strategy

52 Overcladding strategy Block C Block B Block A

53 Overcladding strategy Staircore Block C Staircore Block B Block A

54 Overcladding strategy Staircore Block C Staircore Block B z Block A Overcladding detail External wall

55 Capital Cost Breakdown Foundations Below DPC Internal Wall Insulation External Wall Insulation Roof Insulation Thermal break pads Windows MVHR/Extract Strip out existing ducts Strip out asbestos Airtightness and quality control Prelims, design fees & risk, bond, contingency

56 Capital Cost Breakdown Foundations Below DPC Internal Wall Insulation External Wall Insulation Roof Insulation Thermal break pads Windows MVHR/Extract Strip out existing ducts Strip out asbestos Airtightness and quality control Prelims, design fees & risk, bond, contingency Bill of quantities relevant items Item cost Total Cost to summary Running total

57 Foundations Passivhaus requirements

58 Foundations Passivhaus requirements Part L 2010 equivalent

59 Foundations Bill of quantities relevant items Bill of quantities relevant items 200 mm XPS Insulation No Insulation required Total Cost to summary Total Cost to summary nil Running total Running total nil Passivhaus requirements Part L 2010 equivalent

60 Below DPC Passivhaus requirements

61 Below DPC Passivhaus requirements Part L 2010 equivalent

62 Below DPC Bill of quantities relevant items Bill of quantities relevant items Balcony base detail Stair core base detail 718 Balcony base detail Stair core base detail 330 Total Cost to summary Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

63 Internal Wall Insulation Passivhaus requirements

64 Internal Wall Insulation Passivhaus requirements Part L 2010 equivalent

65 Internal Wall Insulation Bill of quantities relevant items Ground floor façade walls Upper floor façade walls Stair core façade walls Total Cost to summary Bill of quantities relevant items Ground floor façade walls Upper floor façade walls Stair core façade walls Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

66 External Wall Insulation Passivhaus requirements

67 External Wall Insulation Passivhaus requirements Part L 2010 equivalent

68 External Wall Insulation Bill of quantities relevant items EWI / brick slip cladding Render panels to facades Rainscreen to facades Render panels to stairs Total Cost to summary Running total Bill of quantities relevant items EWI / brick slip cladding Render panels to facades Rainscreen to facades Render panels to stairs Total Cost to summary Running total Passivhaus requirements Part L 2010 equivalent

69 Roof Insulation Passivhaus requirements

70 Roof Insulation Passivhaus requirements Part L 2010 equivalent

71 Roof Insulation Bill of quantities relevant items Bill of quantities relevant items Parging panels (airtight) Rockwool to rafters No parging required Rockwool to rafters nil nil Warmdeck roof coating Total Cost to summary Running total Warmdeck roof coating Total Cost to summary Running total Passivhaus requirements Part L 2010 equivalent

72 Thermal break pads Passivhaus requirements

73 Thermal break pads Passivhaus requirements Part L 2010 equivalent

74 Thermal break pads Bill of quantities relevant items Bill of quantities relevant items Thermal break pads Thermal breaks not required Total Cost to summary Total Cost to summary nil Running total Running total Passivhaus requirements Part L 2010 equivalent

75 Windows Passivhaus requirements

76 Windows Passivhaus requirements Part L 2010 equivalent

77 Windows Bill of quantities relevant items Bill of quantities relevant items upvc windows brise soleil upvc windows brise soleil Total Cost to summary Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

78 MVHR/Extract Passivhaus requirements Part L 2010 equivalent

79 MVHR/Extract Passivhaus requirements Part L 2010 equivalent

80 MVHR/Extract Bill of quantities relevant items Bill of quantities relevant items Mechanical ventilation heat recovery Extract fans Total Cost to summary Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

81 MVHR Boxing Bill of quantities relevant items Bill of quantities relevant items Fire rated proprietary suspended ceiling MVHR boxing not required nil Total Cost to summary Total Cost to summary nil Running total Running total Passivhaus requirements Part L 2010 equivalent

82 Strip out existing ducts Passivhaus requirements

83 Strip out existing ducts Passivhaus requirements Part L 2010 equivalent

84 Strip out existing ducts Bill of quantities relevant items Bill of quantities relevant items Strip out ducts Ducts retained nil Total Cost to summary Total Cost to summary nil Running total Running total Passivhaus requirements Part L 2010 equivalent

85 Strip out asbestos Passivhaus requirements

86 Strip out asbestos Passivhaus requirements Part L 2010 equivalent

87 Strip out asbestos Bill of quantities relevant items Bill of quantities relevant items Asbestos removal (in connection duct removal) Lesser scope of asbestos removal Total Cost to summary Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

88 Airtightness and quality control Passivhaus requirements

89 Airtightness and quality control Passivhaus requirements Part L 2010 equivalent

90 Airtightness and quality control Bill of quantities relevant items Bill of quantities relevant items Passivhaus airtightness/ consultant Lesser scope of service Total Cost to summary Total Cost to summary Running total Running total Passivhaus requirements Part L 2010 equivalent

91 Total construction costs Summary Adjusted works Non adjusted works Oncosts Total Additional Cost Passivhaus

92 Total construction costs Summary Adjusted works Non adjusted works Oncosts Total Additional Cost Summary Adjusted works Non adjusted works Oncosts Total Additional Cost 9% Passivhaus Part L 2010 equivalent

93 Breakdown of capital cost differences Enerphit Contract Sum 12,927, /m² Building Regulations 11,836, /m² Difference 1,090,536 75/m² mvhr, $370, $400, Contract Bond, $5, $350, airtightness and quality control, $117, $300, $250, $200, $150, $100, $50, thermal break pads, $10, Roof insulation, $55, extract fan, $(48,600.00) stripout asbestos, $60, stripout existing ducts, $39, mvhr boxing, $30, Contract Contingency & Dayworks, $29, Contract Design Fees & Risk, $59, Contract Prelims, $181, $- Saving $(50,000.00) External wall insulation, $120, Internal wall insulation, $20, windows, $34, Below DPC, $1, Foundations, $1,149.61

94 3. Lifecycle cost analysis Passivhaus specification (as tendered) Building regulations equivalent (Part L 2010)

95 Energy calculations Passivhaus requirements

96 Energy calculations Passivhaus requirements Part L 2010 equivalent

97 Running costs for a passivhaus $20, $- Annual maintenance (2no filter changes) - per dwelling, $(20,000.00) $(40,000.00) Annual ventilation cost - per dwelling, $(60,000.00) $(80,000.00) $(100,000.00) Space heating saving - Per dwelling, Across scheme- 98,227.08

98 Life cycle cost NPV 30 years Positive NPV reached by close of 15 th year NPV for 30 Year Period 617,181 $1,000, $800, $600, $400, $200, $0.00 -$200, $400, $600, $800, $1,000, Positive NPV Years NPV 30 Years + 617,181

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100 PCC Report to Cabinet Member for Housing Source: Portsmouth City Council Nov 2012 Comments from the Head of Finance: Wilmcote House is over 40 years old. Without refurbishment it will be uninhabitable in the medium term and costly to maintain in the short term. The [PCC] financial appraisal of the scheme demonstrates that the high specification of work is cheaper over the 30 year plan than demolition and replacement. The energy saving measures proposed will in addition reduce the ongoing running costs of the block. 100

101 4. Other Reasons 101

102 A. Health & Wellbeing B. Safety & Security C. Employment & Economy D. Changing perceptions 102

103 HEALTH & WELLBEING Marmot Review (2011) BRE Impact of DH works (2014) Oldham CCG report (2015) Coastline Housing study (2015) 103

104 SAFETY & SECURITY 104

105 EMPLOYMENT & ECONOMY 105

106 CHANGING PERCEPTIONS 106

107 Thank you. ECD Architects Ltd, Studio 3, Blue Lion Place, 237 Long Lane, London SE1 4PU T: