Marylebone s first Passivhaus

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1 Marylebone s first Passivhaus The experience of the Portman estate Mark Hopkins, Associate Director The Portman Estate October 2018

2 Drivers for Passivhaus Maintain the Estate s position as a leading provider of high quality accommodation in Marylebone Enhance the Estate s reputation Signal the Estate s ambition to reduce its carbon emissions - CSR Context UK Climate Change Act 80% reduction in carbon emissions by % of carbon emissions in Westminster are from buildings 85% of today s buildings will still be in use by 2050 To test our, and our suppliers, ability to upskill and build to this standard Readiness for potential future changes to Building Regulations and MEES Approved Document L1B All residential rented properties to achieve minimum EPC C rating by 2030? No complex and costly active systems Improve Indoor Air Quality, comfort, health and wellbeing for our residents Reduced running costs for tenant

3 Barriers to Passivhaus Passivhaus is a voluntary standard Additional cost and time Skills shortage A lack of suitable properties Heritage and conservation Risk of unintended consequences fear of the unknown Lack of market demand and public awareness Restrictions on occupants perception or reality?

4 Project Objectives Retain look and feel of a typical high end refurbishment carried out by the Portman Estate To have no detracting features No restrictions on occupant behaviour Limited additional maintenance liabilities Maintain cost certainty and value for money To environmentally exceeds all other properties on the Estate and set a new benchmark To maintain, or preferably increase rental and capital value To receive positive feedback from the tenant and asset management team

5 Why 2 Gloucester Place Mews? Self-contained house Substantial reconfiguration and repair needed to existing building Added capital and rental value by converting four car garage to additional bedroom Inherent positive characteristics orientation, existing rooflight, (passive stack ventilation) small fenestration to north and west elevations (reduced heat loss), space for plant room Some shading from cornice and tower blocks opposite on south elevation (reduced solar gain) Excellent cross flow ventilation (rapid cool down) Retained single car garage outside of envelope provides a secure cool storage area 2 Gloucester place mews

6 Construction challenges Thermal bridging deep pockets required Airtightness Volume of bespoke detailing a small but complex building Retained historical features insulating behind retained staircase and wall plate Fixing of aerogel to wall special fixings had to be designed and approved Specialist skim plaster and paint for magnesium oxide drylining Long lead times for overseas materials were successfully factored in Constant supervision of staff

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11 Lessons Learned - client Obtain buy-in from the top we are in this together Involve stakeholders Asset managers, facilities managers, maintenance contractors Remain committed focus on the positive outcome, do not compromise on quality Foster a positive project culture avoid blame, accept the learning curve, people will make mistakes Allow additional contingencies time and cost Rigorous approach to cost planning and risk management Get the right people on board End user training and education. Obtain permission for monitoring Manage expectations although it is a Passivhaus, it still does not have air conditioning! A heritage building is not an automatic barrier

12 Lessons learned - designers Ensure building is fully surveyed during detail design stage leave no stone unturned Be honest with your client about the time and supervision required Ensure quality of all specified products. E.g. windows and doors - handles may not be supplied with product Do not over complicate building services design and controls - remember the end-user Passivhaus may not be suitable for buildings with irregular shapes or lots of corners and junction details Allow for maintenance cavity behind internal boarding to prevent accidental damage to membrane Architect / Passivhaus Designer to attend site often to ensure construction is exactly as per design

13 Lessons learned - contractor Order materials as early as possible to avoid delays. Materials often come from abroad and have long lead-times Purchase own air testing machine Allow programme contingency for air tightness detailing, additional air testing, re-work Train all operatives in airtightness. More control over directly employed staff In-house M&E operatives was an advantage Air tightness champion to supervise all operatives and maintain responsibility Do not rush Lean on professional team for expert advice Beware of optimism bias there will be challenges

14 Results & POE Final airtightness test score: 0.68 ach (Initial air test: 23 ach) EPC B* BREEAM Excellent 75% reduction in CO 2 emissions First listed building in the UK to be certified to Passivhaus (EnerPHit) standard Energy and IAQ monitoring underway with consent from tenant 1 year post-occupancy evaluation report to be produced in March 2019 UK s hottest summer since 1976 overheating? Excellent sound insulation Quality is evident. You get what you pay for *EPC A if PVs installed Marylebone Journal April 2018

15 Results against Project Objectives To retain the look and feel of a typical high end refurbishment carried out by the 10 Portman Estate To have no detracting features 9 No restrictions on occupant behaviour 8 Limited additional maintenance liabilities 8 Maintain cost certainty and value for money 6 To create a quality product which environmentally exceeds all other residential 10 properties on the Estate and sets a new benchmark To at least maintain, or preferably increase its rental and capital value 8 Our Score To receive positive feedback from the tenant and asset management team 8 67/80

16 The important questions Should we be targeting the reduction of carbon emissions in heritage buildings? Is Passivhaus the answer? Does Passivhaus need more support from the Government, e.g. encouragement and incentives? Are Passivhaus homes marketed in the right way? Is comfort the key? (L-R) 11 Passmore Street, 13 Adams Row, 29 St Barnabas Street, 126 Pavilion Road, 2 Gloucester Place Mews