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Persuading your ClientA rapid cost benefit for Green Roof Technology

Presented by: Liam Foster

Sheffield Green Roof Forum

22nd November 2007

PREVIOUSLY PRESENTED TO

Green Roofs 2007 Conference

Opportunities for Architects in

the Green Roof Industry

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Persuading your client

Focussing on the opportunities for surface water management:

Hydrology

Surface Water Management

What does a Green (Living) Roof do to a structure ?

Why are costs seen as prohibitive ?

What are the financial benefits ?

What about added value for your client ?

Topics for discussion

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Conventional hard engineering Collect and remove from area

SUDS The Management Train principle Replicate the natural environment

Ways to manage surface water

Green roofs a good way to get SUDS off the groundBrian DArcy (SEPA)

Green Roofs mimic nature

Storing water volume within layers Delaying water run-off affecting time of concentration Losing water through evaporation

From: www.ciria.org.uk

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Effect on Structure

But Less if included earlier in design process

Green roofs not suitable for all buildings Move away from inefficient buildings -

Part L Building Regs

Plainly speaking Represents some additional loading:

Foundations Columns

Additional roofing materials Construction

= Opportunity !

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Using Green Roofs can reduce need for below ground attenuation structures

Consider cost of building as a whole not individual segments

Encourages better management of fees

Increased opportunity to avoid cuts - value engineering

What does the client need to know ?

Increased focus on sustainability & environment

Structural costs can be offset by reductions in development charges/rates

Section 106 requirements

Developer infrastructure charges

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Local Issues

High groundwater table

City Centre Location

Geological conditions

River Rea Response - Flashy

Sustainable Eastside - Introduction

Thus traditional ground level

SUDS have limited use !

20 25 year redevelopment profile need for strategy

High percentage of impermeable area relatively low times of concentration

Capacity of existing network largely combined

Main network run to Minworth WwTW surcharged in 1 in 5 year event

Minworth WwTW - near capacity

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Green roofs can save money for:

Each developer

Birmingham

UK Plc

Identified that strategic solutions would be best with policy to guide

greening of developments

Sustainable Eastside - Findings

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Site Q Existing4.75 hasite

No Green Roof = 106m3of attenuation (1 in 30yr).

With green roof = 0m3of attenuation.

Sustainable Eastside Example Development (1)

Land Value c. 5 m/acreLand Area required = 106 m

Approximate construction cost = 106k (~1000 per m)

Approximate land value = 1235.83 per m = 123,583

TOTAL SAVING = 229,583 (uncontaminated ground conditions)

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Based on Site Q Total roof area ~ 1.8 ha

Overall building construction ~ 1000 per m Value ~ 18m

Approximate structural cost ~ 40% of Value

Value ~ 7.2m

Approximate structural cost of roof ~ 7.5% of structural costs

Value ~ 540,000

Increase in roof cost to accommodate a Green Roof (extensive)

conservatively15% higher build cost for foundations & structures 81,000

Cost Benefit = 230k - 81k =149k saving

Sustainable Eastside Example Development (2)

INTERESTED ?

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Sustainable Eastside - Benefits

Drainage & network benefits Private Developer

SAVES MONEY

Reduce unnecessary below ground attenuation

Reduce need for external pipe works

Nicer living/working environment easier to sell

Drainage & network benefits Public

Alleviate overloaded sewerage system

Avoid heavy investment in artificial drainage systems. Underpin long-term development programme for Eastside

Reduce future energy costs & carbon emissions

Improve water quality in the River Rea.

Winning of other benefits

Improve central Birmingham biodiversity regime

Improve micro-climate

Assist meeting current sustainability criteria

Photo: Craig Churchill

Photo: Carlisle 2005 (BBC News)

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Planning, Legislation, building requirements, etc

Emerging Requirements

Climate Change & Carbon Emissions

Code for Sustainable Homes DCLG (2006) The London Plan Energy Strategy Zero Carbon Buildings (2006)

The Building Regulations (Part L) BRE (2006) UK Sus. Devt Strategy: Securing the Future (2005)

Flooding European Floods Directive (~October 2007) Tougher requirements to limit surface water from development sites

PPS25 Development & Flood Risk DCLG (2006) UK Government - Making Space for Water (on-going) Designing For Exceedance (CIRIA, 2006)

Water Environment European Water Framework Directive (2000)

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Developer (for disposal)

Tangible

Lower build costs Reuse of materials onsite

Intangible

Green credentials BREEAM etc

Marketing

Quicker on-sale

Additional benefits

Developer (for retention/leasing)

Tangible

Lower build costs

Building insulation & efficiency (energy)

Building management (yields & voids)

Increased roof life (membrane)

Intangible

Ongoing green credentials

Inhabitants happier Amenity Space

Public Benefits

Reductions in Urban Heat Island

Improved Air Quality

Reduce flooding potential

Cleaner water in rivers Aesthetic benefits community well-being

ESSENTIALLY GREEN ROOFS AND SUDS

USEFUL CLIMATE CHANGE ADAPTATIONTOOL:

STORMWATER RUN-OFF REDUCTION COOLING OF BUILDINGS LESS ENERGY

BIODIVERSITY

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Encourage uptake early in design promote and keep the concept

Lump all costs and savings together - Produces different picture

Whole Life costing not accurately reflecting greening potential

Changing policy & move to sustainability = OPPORTUNITY

Final Thoughts

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Hyder are celebrating our 150th anniversary in2007. Please visit our website to see our iconic

projects - www.hyderconsulting150.com

Thank you

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