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Retroft & ReplicateProject Brieng

Project Background: Whilst the environmental focus of the house-building industry has been on new

build and the Code for Sustainable Homes, improving the energy efciency of the nations existing housing

stock presents a far more important challenge in terms of helping to combat climate change. Our existing

stock is typically very inefcient compared to new build housing in terms of energy use, yet less than 20% of

existing homes are likely be replaced by 2050.

ECD Architects have a long-standing interest in this issue and a track record in exemplar refurbishment in

the residential sector. Similarly, Hyde Housing Association have strong policies on sustainability and, with

responsibility for over 40,000 dwellings mainly around the south and south-east of England, they were alsovery interested in the potential of low-carbon refurbishment. ECD approached Hyde late in 2007 with a

proposal to undertake an exemplar retrot project and in January 2008 they identied a suitable void property

- a 3-bedroom mid-terrace house in Mottingham, south-east London, typical of their stock.

Most analysis of retrot focuses on targets for reducing carbon emissions - the Governments Energy White

Paper (2007) ofcially stated the UKs target to reduce its net carbon emissions by 60% by 2050, which will

become a legal obligation once the Climate Change Bill is passed (currently due late 2008). The Review

of Sustainability of Existing Homes, produced by the Department for Communities & Local Government in

November 2006, declared that the countrys existing housing should fall in line with this target.

However, the Existing Homes Alliance and others argue for greater targets the EHA Declaration states

deep cuts of at least 80% in carbon emissions are needed by 2050, with major progress by 2020. Recentproposals suggest that the Government is likely to adopt this higher target. The EHA Declaration goes further

to propose the approach that must be taken with regard to our existing dwelling stock - Government and

industry action should focus on developing a whole house approach which applies packages of low carbon

improvements, rather than individual measures, using existing, proven energy efciency and microgeneration

technology. Improvements to water and other resource use efciency must be included. A whole-house

approach brings greater economic savings to business and causes less disruption to households over time.

Retrot initiatives to date have indeed focussed primarily on installing individual renewables or other low-

carbon technologies. Hyde and ECD therefore agreed that the aim of this project would be to establish the

most effective overall package of retrot measures necessary to achieve the 80% reduction in CO2

emissions

at the Mottingham house and to monitor the performance of the low-carbon improvements in use. In addition,

it will record the impact of the retrot on the incoming tenants over a 24 month period and, at the end of that

time, develop a full cost/benet analysis, with a view to ascertaining the optimum expenditure. This will enable

Hyde and others to make the more efcient and effective choices about how best to apply energy saving

as part of large scale retrot programmes. This project will therefore be of huge benet both in terms of the

developing national policy and of helping to frame the approach of individuals and organisations to retrot.

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The Existing Property: 225 Court Farm Road is thought to have beenoriginally constructed in the late 1930s as part of a large estate development.

The external walls are of cavity wall facing brick construction and the original

dwelling included suspended timber oors and pitched tiled roofs but no

bathroom! Later improvements saw the inclusion of a rst oor shower

room, the replacement of open res with a central heating system of

gas combination boiler with radiators and the addition of a single-storey

rear extension comprising a third bedroom and ensuite bathroom. Fabric

improvements over time have seen the addition of double glazing (though

of poor quality) and 100mm loft insulation to the pitched roof, though the at

roofed extension included only 25mm mineral wool insulation. A solid concrete

oor replaced the timber in the kitchen and the strip out works found that the

original water supply was via lead piping and an asbestos tank, with no stop-cock found on the premises. Further asbestos was found in the soft boards.

Initial design proposals investigated the potential for a loft conversion at the property but this was eventually ruled

out due to a lack of headroom. There is an imperative to enlarge the rst oor shower room and further space is

required for hot water storage and electrical equipment (inverters, dataloggers etc). SAP assessments were carried

out by ECD Project Services for the property, which was found to have a rating of 60, well above the national

average of 48 and therefore presenting a signicant challenge to achieve the 80% reductions. In March 2008,

ECD assigned Heathrow Commissioning to undertake a before airtightness test. The purpose of this test was to

provide a base case with which to compare the completed scheme and to highlight existing leakage points that

need mitigation. The results were surprising 9.16 m3/hr/m2 @ 50 pascals, which is better than current building

regulation requirements. The windows were the source of the worst inltration with poor seals leaking air badly,followed by incoming services penetrations and the loft access hatch.

According to PHPP software, specic primary energy use (heating, DHW + auxilliary electricity) at the existing

property is estimated to have been 414 kWh/m2/yr with CO2 emissions rated at 100 kg/m2/yr and space heating

demand rated at 223 kWh/m2/yr.

Design Team: ECD Architects are lead designer for the project and are drawing on their sister company,

Keegans, to provide extensive cost consultancy and CDM co-ordinator services. Further consultancy input has

been forthcoming from Parity Projects, with particular responsibility for the data monitoring aspects of the project.

In addition to this quantitative feedback on energy and water use, another of ECDs sister companies, PPCR,

will undertake post-occupancy evaluation interviews with the incoming tenant providing valuable information on

comfort and satisfaction.

Following interviews and competitive submissions, Mears Ltd were selected as main Contractor partner and

began working with ECD to develop the specication. Mears, in turn, introduced Travis Perkins and Kingspan assupply chain and technical partners respectively. We are working to a total capital budget of 80k (including VAT

and fees) funded in the main from Hyde internal resources but with all partners and product contributors investing

signicant resources in the project. A full list of supply partners and their involvement has been included at the end

of this document.

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The Retroft Proposals: The Retrot

and Replicate strategy focuses on carrying

out the most straightforward improvements

to reach the 80% target . . . and on doing

them well. The priorities are to minimise

heat losses from the building fabric; to install

an easily replicable, efcient form of space

and water heating; to reduce the energy

requirements for lighting; and to utilise

the most appropriate renewable forms of

micro-generation in reducing CO2 emissions

associated to the property.

Heat loss will be addressed though

signicantly improved insulation to oors,

external walls and roofs, replacement

high-performance windows and doors,

consideration to the dwellings air permeability

and the installation of a mechanical

ventilation system with heat recovery from the

extract air. In the choice of insulation material,

thermal performance and ease of installation

has been favoured over embodied energy

and material source considerations, although

minimal GWP and ZODP credentials were

pre-requisites. U-value targets for the various

envelope build-ups were set as follows:

Suspended timber oor 0.2 W/m2K

External walls 0.15 W/m2K

Pitched or at roofs 0.1 W/m2K

Phenolic foam insulation offers the best

performance of any readily available panel

and therefore has less impact on internal

room dimensions where dry-lining is

concerned an important consideration for

Hyde. Kingspans Kooltherm phenolicrangewas therefore selected for both suspendedoors and external walls. For the main

body of the house, insulation-backed K17

plasterboard dry-lining panels were specied,

whilst for the rear extension external K5

wallboards with a silicone render nish

provides the best solution. This element

of the works was supplied and installed by

Wetherby Building Solutions.

For the rear extension roof Kingspan

Thermapitch rigid polyurethane boards

(220mm) were preferred, in conjunction with

Knauf Carbon Zero glasswool in the eaves

location.

For the pitched roof element, a number of

other factors came into play rather then

straightforward thermal performance.

The loft is to be used for locating plant

such as the proposed thermal store and

mechanical ventilation unit, therefore access

and available headroom were important

factors, as was the poor condition of the

existing roong felt. Simultaneously, we

were concerned about achieving good

airtightness when recessed light ttings were

introduced to the ceiling below. A combination

of insulation products were therefore

selected Kingspan Thermapitch, laid on

an airtight vapour barrier over the existing

ceiling joists, and Web Dynamics TLX Goldmulti-foil lining the existing rafters and party

walls. The rigid boards are laid to the depth

of an existing central bearer (170mm), thus

allowing a oating oor deck to pass freely

across the loft area. TLX Gold is the worlds

rst breathable multi-foil and the Court Farm

Road project will be used as a case study

and test-bed for both its ease of installation

and performance in operation. This material

will also allow the retention of the existing

roong felt and tiles by providing a secondary

waterproof layer, as well as minimising the

impact on headroom in the loft and reducing

summer heat gains due to its reective gold

inner layer.

The existing double-glazed windows were

shown to be the weakest building elementduring the airtightness test: they will be

replaced with aluminium-clad NorDan Ntech

Passive windows, which are triple-glazed with

warm edge spacers and composite insulated

timber frames, achieving an overall Uw-value

of 0.7 W/m2K. Front and rear doors will also

be replaced with insulated replacements with

a Uw-value of 1.0 W/m2K.

Details have been considered in terms of

the abutment of insulation, avoidance of

thermal bridging and continuity of the airbarrier. As well as communicating installation

requirements on 1:5 detail drawings, ECD

held a workshop on site with Mears site

team to explain the importance of their

workmanship to these issues, together with

background on how the building is intended

to perform as a low-carbon dwelling. To

ensure a reasonably airtight envelope, Mears

will keep a log and photographic record of

all service penetrations through the external

walls and roofs to ensure they are sealed

effectively.

To provide controlled ventilation, a Vaillant

recoVAIR 275 mechanical ventilation

system is being retrotted into the property.

Mounted on the party wall in the loft space,

the unit will extract air from the kitchen and

bathrooms, reclaiming around 90% of the

heat to pre-warm incoming fresh air which

is then supplied to the living and bedrooms.

In summer mode, a bypass extracts the air

direct to outside.

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With these measures in place, the space

heating requirements at the property are

estimated to reduce from 17,238 kWh/yr to

2,410 kWh/yr a drop of over 86%. With such

low levels of heating required, tenant fuel

bills will be signicantly reduced. Capital cost,

ease of retrotting and ongoing maintenance

requirements therefore become the most

important driver in the choice of fuel source.

Ground source heat pumps are relatively

expensive to install and need to be located

in a substantial, and preferably sound-

proofed, cupboard. Furthermore, to operate

efciently they work best in conjunction with an

underoor heating system, which in itself has

inherent problems in a retrot situation.

The feasibility for underoor heating was

explored by ECD and Mears and found to be

technically possible but only with a reduction

in underoor insulation levels and an increase

in installation time and cost. When further

confronted with a solid concrete oor in the

kitchen, the concept was rejected in favour of a

conventional wet radiator system. Heat pumps

require electricity to operate, which in the UK is

particularly carbon intensive more than twice

the kgCO2/kWh than mains gas. Therefore to

produce carbon reductions in comparison with

an efcient gas condensing boiler, heat pumps

need to achieve a Coefcient of Performance

greater than 2.5 measured across the whole

year the recent trials at the Barratt EcoSmart

show properties recorded a CoP of 2.6. Air

source heat pumps are unlikely to improve

upon these results at present and would also

require underoor heating. A biomass boiler

was also ruled out by Hyde as it was thought

to place an undue burden on the tenant to

source and store a supply of wood pellets,

and would again require additional plant

space. With these considerations in mind, the

decision was made to upgrade the existing

gas boiler for a more efcient condensing unit

and the Vaillant ecoTEC system was selected,

with low NOx emissions and programmable

controls. This was relocated to a hall

cupboard since the existing ue outlet position

contravened modern guidelines.

The gas condensing boiler will also supply hot

water to the property but will be supplemented

by solar thermal collectors located on the

pitched roof. The system is to be supplied

and installed by Kingspan Renewables in

conjunction with a twin-coil 250l Range Tribune

thermal store located in the loft space. Two

at plate collectors mounted either side of

the ridge will face east and west but will be

controlled intelligently to favour the better

performing panel as the sun tracks around

the house to the south. It is hoped that 50-

60% of the tenants hot water needs will be

met by this system. All connecting pipework

between boiler and thermal store will be well

insulated to prevent heat transfer to the internal

environment.

A signicant proportion of the propertys

electricity load will be for lighting therefore

the retrot proposals will seek to minimise

this component. Other major demands for

electricity, eg for household appliance and

entertainment use, are typically beyond the

control of any RSL refurbishment scheme

and down to tenant behaviour. The Retrot

and Replicate exemplar project therefore

concentrates on minimising electrical lighting

loads through the installation of low energy

lighting to every room. However, unlike

typical low energy lighting solutions, the use

of compact uorescents will be avoided in

favour of the latest in LED technology. Unlike

CFLs, LED lamps contain no contaminants

such as mercury or phosphor and can be

safely disposed of or recycled. Although they

are much more expensive currently, they

are very robust and offer 50,000 hours of

use (compared to 10,000 for CFLs or 3,000

for halogens) meaning no need to change

then for at least 20 years! In this way, energy

use is signicantly reduced without the

customary start-up delays and only a small

reduction in efcacy. ECD have worked with

Gloucestershire-based specialist GreenLED

to develop the layouts and specications.

GreenLED will supply 3.7W Antares GU10

lamps for installation by Mears into standard

recessed ttings.

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Though driven primarily by low-carbon

targets, the project offered an opportunity to

incorporate other sustainable refurbishment

measures. Water conservation measures

are also a key interest for Hyde and the two

bathrooms will subsequently be tted with

Twyford Galerie Flushwise (2.6l/4.0l dual-ush) wcs, aerated basin taps, Mira Eco

shower handsets and a low volume bath. The

project team did not consider conventional

rainwater harvesting, stored underground

and pumped up to a header tank, to be

viable for a stand-alone property - primarily

in terms of the installation and maintenance

costs but also in terms of energy and carbon

savings. A recent study by the Centre for

Alternative Technology (CAT) has proven

that the embodied energy consumed in the

manufacture of buried tank systems is never

paid back through its life by the savings made

from utilising rainwater. However, Retrot

and Replicate partners Parity Projects haveexperience of installing simple gravity-fed

harvesting systems and have designed a

proposal based around a ltered 318 litre

tank located in the void above the stairs.

The tank is fed directly from an external

downpipe, requires no pumps and therefore

requires no parasitic electricity and next to no

maintenance. Parity Projects calculations

indicate that virtually all of the water required

for ushing could be supplied from the annual

average rainfall locally. A meter on the back-

up supply will determine actual annual mains

water consumption.

Despite all the carbon reduction measures

described above, the scheme was still

estimated to fall short of achieving the

80% target, largely because of its relatively

good SAP rating at the outset. Bridging the

shortfall would require the input of renewable

electricity micro-generation, with photovoltaics

considered the only viable solution. Working

with Solar Technologies, proposals for an

array of eight panels located on the rear

extension roof were developed. Bearing

in mind the short lead-in time, product

availability and the need for grant funding,

Solar Technologies recommended Sharp

170W polycrystalline panels, to be laid at

a pitch of only 5 to limit any impact on the

neighbouring property. A single inverter

has been located in the existing electrical

cupboard and a wall-mounted display will

inform the incoming tenants of its electrical

contribution.

The graph opposite shows the impact that

each of the measures implemented at

the property have on the associated CO2

emissions. The insulation measures alone

account for over a quarter of the original

emissions, or a third if the triple glazing

is included. The greater efciency of the

condensing boiler then takes the improvement

to over 50%, after which the returns on

investment are less dramatic. Nevertheless,

the introduction of MVHR and airtight

construction should contribute a further 15%,

with the solar thermal and LED lighting taking

our overall reduction to 76%! The photovoltaic

contribution allows the refurbishment to easily

achieve the target with a built-in contingency

for actual performance in use. The high levels

of energy conservation and generation are

reected in the provisional EPC rating of 92,placing the property in the highest Band A.

Predicted specic primary energy use at the

refurbished property is estimated at 67 kWh/

m2/yr with CO2 emissions reduced to 17 kg/

m2/yr and space heating demand reduced to

32 kWh/m2/yr. Fuel poverty should never be a

concern for one lucky tenant!

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Materials specications generally reects the

environmentally-friendly aims of the project,

for example:

FDT Rhepanol pvc-free single-ply roof

membrane to the rear extension

Finnforest Thermowood fascia cladding

boards

Lindab Rainline steel guttering

These materials have been selected because

their manufacture and processing avoidsthe use of toxic materials. Typically they

are durable products that require minimal

maintenance and can be easily recycled at

the end of their life.

Internally, the focus has been on responsible

sourcing and avoidance of materials prone

to off-gassing wherever possible. This is

especially important in a dwelling where air

leakage and draughts are very low. Timber

used throughout the house is either softwood

or occasionally temperate European

hardwood, with FSC or PEFC accreditation.

Natural products have been selected for

oor nishes as far as possible, with TarkettMarley Veneto XF linoleum ooring in the

kitchen and an eco-wool carpet to bedrooms

and hall areas supplied by the Alternative

Flooring company. The latter has even been

laid on a recycled rubber underlay!

The access door to the rainwater harvesting

cupboard was fabricated in MDF for ease but

the zero-formaldehyde Medite Ecologique

was used in lieu of conventional breboard.

In the garden and driveway the tenant has

been provided with the tools to help with a

greener lifestyle, for example:

raised planter to encourage home-grownvegetables

twin composting bins

rainwater butt to store water for use in

the garden

a rotary

washing

line

recycle

box

storage

Internal decoration has been carried

out throughout the entire house post-

refurbishment paints were generously

supplied by Dulux Trade from their Ecosure

and Light&Space ranges. Working with

consultants from their in-house team,

the specications have been selected to

highlight their performance credentials,

whether that be low VOC levels in the

bedroom environments, improved durability

and lifespan in the hallways or increasedlight reectance in the living areas. The

Dulux team will then benet from the tenant

feedback on the performance of these paint

nishes over the two year monitoring period.

In addition to carrying out the

comprehensive eco-refurbishment, Hyde

will provide the incoming tenants with an

understanding of how to best maximise

energy savings and to optimise use of the

property. We will then comprehensivelymonitor the propertys performance whilst in

occupation, in order to give us a thorough

understanding of what technologies best

work in terms of CO2

savings, energy

efciency and cost effectiveness. Working

with Parity Projects, thermocouples are

being installed across all wall and roof

constructions. These temperature readings

will be recorded and uploaded directly to a

datalogger, together with ongoing electrici ty,

gas and water usage. Furthermore, a heat

meter linked to the output of the Vaillant

ecoMAX condensing boiler will provide

details of the actual energy used for space

heating and supplementary hot water at

the property. Uploading this information to

a PC-based software package will allow

continuous remote monitoring and analysis

of the propertys energy use and emissions.

In addition to the quantitative data PPCR

will undertake post-occupancy interviews

conducted throughout the monitoring

period to assess resident reactions to

the eco measures employed and their

impact on comfort and satisfaction. Therefurbishment can greatly reduce carbon

dioxide emissions, but another crucial

question is: Whats it like to live in? PPCR

will conduct a complimentary exercise

with a family living in a nearby similar but

non-refurbished property as a comparator.

They will discuss general aspects through

a questionnaire type agenda with each

household member able to contribute, for

example:

Does living here seem any different to

another home of this type?

Does the ecohome present anyrequirements for lifestyle changes?

Are there any aspects of the measures

that are difcult to use/understand?

Are there any measures you would like

to change? Why?

Do you think it would work for all

tenants/families?

What are the benets of living in aneco-home?

Of equal importance to reductions in

carbon emissions are the nancial savings

to residents resulting from the signicant

reduction in energy consumption. We

estimate that energy consumption will be

reduced by up to 85% with a saving to

the residents of around 600 per year as

a result of the retrot we are carrying out

(at current energy costs). This project can

therefore make a major contribution to the

growing problem of tackling fuel poverty.

At the end of the project we will be able toproduce cost benet analysis for each of

the eco measures adopted. This information

will be disseminated publicly and will

specically inform Hydes future stock

investment and refurbishment plans.

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Dulux Trade are providing paint nishes and specication advice for the project, featuring their Ecosure and

Light&Space emulsions. www.dulux.co.uk.

Travis Perkins is the UKs leading builders merchant and supplies more than 100,000 product lines to the

trade. These include building materials, plumbing and heating, landscaping materials, timber and sheet

materials, painting and decorating, dry lining and insulation, tool and equipment hire, doors and joinery,

bathrooms and kitchens and hand and power tools, along with a wide range of services including the trade-

dedicated website, Trademate.

www.trademate.co.uk.

Specialising in the design and manufacture of intelligent textile solutions, Web Dynamics have supplied

and installed the worlds rst breathable multi-foil insulation, TLX Gold, across the entire pitched roof space.

www.webdynamics.co.uk.

Vaillant have supplied their A-rated ecoTEC Plus 612 condensing boiler as well as their recoVAIR 275 whole-

house mechanical and ventilation system featuring heat recovery and summer by-pass. www.vaillant.co.uk.

NorDan UK Ltd, suppliers of Norwegian high performance windows and doors, are supplying and

installing their market leading Ntech Passive range triple-glazed frame insulated windows and doors.

www.nordan.co.uk.

Kingspan have provided technical advice and assistance focusing in particular on insulation products and

solar thermal collections. They have supplied the project with Kooltherm and Thermapitch insulation products

and have supplied and installed their dual-facing Marvel at panel solar thermal collectors, controls and Range

Tribune cylinder.

www.kingspan.com.

Working under the British Gas Framework, Solar Technologies will supply and install 8 x 170w Sharp

polycrystalline photovoltaic panels and display monitors. www.solartechnologies.co.uk.

GreenLED, the new force in sustainable lighting, are supplying the latest in LED downlighter technology to

the entire house and have designed lighting layouts based on the use of their Antares 3.7W GU10 lamps.

www.greenled.co.uk.

Wetherby Building Systems Limited have supplied and installed the external insulated render system to

the rear extension, based on phenolic insulation boards and a proprietary silicone-bsed render nish.

www.wbs-ltd.co.uk

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Key Stages to date and beyond Dates

Assessment of retrot options and nalising specication End July 2008

Commencement of retrot July 2008

Launch Event to mark completion of retrot October 2008

Information to incoming tenants on energy saving and optimum use of house November 2008

Monitoring of the property in use November 2008 - Novemb er 2010

Project Impact Assessment and dissemination of ndings April 2009 onwards

Incorporation of lessons learnt into Hyde Stock Investment Programmes November 2009 onwards

For futher information with regard to this project, please contact:

Emma Tedman, Communications Ofcer, The Hyde Group T: 020 8297 5409 E: emma.tedman@hyde-housing.co.uk

Mark Elton, Head of Sustainability, ECD Architects Ltd T: 020 7939 7509 E: elton@ecda.co.uk

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The Hyde Group is a leading provider of affordable housing and makes a signicant contribution

to meeting housing needs and improving peoples quality of life. Hyde is one of the largest

housing association groups working in England, owning or managing over 40,000 homes in

London, Kent, Surrey, Sussex, Hampshire, the East of England and East Midlands. More about

The Hyde Group can be found at: www.hyde-housing.co.uk.

ECD Architects is an award winning architectural practice committed to design excellence,

sustainability and commercial reality. ECDs expertise in environmental and social architecture has

been developed over 28 years, culminating in more than 100 successfully completed projects forlocal authorities, housing associations and private developers, government departments, colleges

and universities. For further information visit our website: www.ecda.co.uk.

As specia lists in Public Participation Consultat ion and Research, PPCR provides a broad range

of tailored consultancy, research and support that focuses on delivering change through resident

involvement. PPCR will conduct post occupancy interviews. For further information visit www.ppcr.

org.uk.

Keegans, an established, multi-disciplinary property and construction consultancy offering a

range of integrated professional services for all types of property design, maintenance and

construction, is providing Quantity Surveying and CDM services to the Court Farm Road Project.For further information visit www.thekeegansgroup.com.

Parity Projects have designed and installed a comprehensive data monitoring scheme which will

provide vital information on energy performance and behavioural factors at the property. In addition

they have designed and installed the bespoke gravity fed rainwater-harvesting system. www.

parityprojects.com.

Mears is the leading Social Housing repairs and maintenance provider in the UK, providing

rapid response and planned maintenance services to Local Authorities and Registered Social

Landlords. We deliver in excess of 3,000 repairs daily to a portfolio of over 500,000 houses

nation wide.

Our customer service philosophy is simply to make tenants smile. For further information visit

www.mearsgroup.co.uk.