why high-quality overcladding? high-rise … · high-rise residential refurbishment why...

+HIGH-RISE RESIDENTIAL REFURBISHMENTWhy High-Quality Overcladding? www.dbfacades.com

+

EXECUTIVE SUMMARY

KEY FEATURES AND BENEFITS OF HIGH-QUALITY OVERCLADDING

PROJECTS

West Whitlawburn, Glasgow

Castle Court, Sheffield

The Pinnacle, Willenhall

Graiseley, Wolverhampton

Alpha House, Coventry

Contents

d+b facades The Packway Larkhill Salisbury Wiltshire SP4 8PY

T 01980 654230 F 01980 653611 E [email protected] www.dbfacades.com

+E x e c u t i v e S u m m a r y

EXECUTIVE SUMMARYOvercladding of residential tower blocks is an established approach to dealing with the problemsassociated with ageing high-rise tower blocks. Overcladding has been employed for 30 years in the UK,thereby providing todays specifiers and purchasing authorities with proven history of the widely varyingdegrees of success that have been achieved depending on the system selected.

The objective of every successful overcladding project is to deliver the lowest cost solution which meets allthe required performance levels and retains a quality, desirable appearance throughout the anticipatedservice life of the overcladding system.

Overcladding systems fall broadly into three categories of cost and quality:

• low-cost/low-quality render

• mid-cost/mid-quality face-fixed board systems

• high-cost/high-quality fixing-free aluminium cassette systems.

Over the years, financial pressures have persuaded many purchasing authorities to specify low-cost/low-quality solutions with far fewer authorities specifying mid- and high-end systems. Today, however, ‘re-overcladding’ schemes are increasingly prevalent whereby low-cost, and to a lesser extent mid-cost,systems have failed and require replacement long before reaching their expected in-service life. In additionto these failures, there are substantial numbers of low-cost systems seen in towns and cities across the UKwhich might look acceptable from a distance but where the appearance of the new overcladding hasrapidly deteriorated within 5 years post-installation, leaving the in-service buildings looking little betterthan the original building to their residents. This will eventually reflect in reduced occupancy and demandfor the undesirable accommodation as well as impact negatively upon the wider neighbourhood.

The business case for high-quality overcladding is compelling but requires a paradigm shift in terms ofthinking, moving away from lowest-cost as the arbiter of system selection and embracing the principal ofsystem longevity. All desired outcomes of an overcladding project relate directly to longevity(cost/performance/appearance/environmental) - it is the common denominator which underpins truesustainability. High-quality aluminium overcladding has an expected in-service life of 60 years, three timesthat of render and twice that of board, enabling it to deliver superior benefits including:

1. Financial- Lowest whole life cost, c.one third that of render- Greatly extended building life c. three times that of render- No maintenance costs

2. Social- Pristine appearance retained throughout the expected 60 year service life- Proven performance with examples of 20-year-old projects still looking as good

as when first installed without cleaning or maintenance- Secret-fixing withstanding close visual inspection- High-quality, desirable appearance resulting in high occupancy and long-term

demand

3. Environmental- Lowest whole-life environmental impact- New building envelope is constructed of predominantly recycled materials

which are 95% recyclable at the end of their 60 year life

With ever-increasing pressure on social housing, tower blocks are a valuable resource and need to beretained for the future, however their desirability is proportional to the quality of accommodationafforded. Even derelict tower blocks can be regenerated to provide accommodation which is in demandproviding they are refurbished to a high standard.

This document examines the benefits of adopting a high-quality approach to external refurbishment fromwhich a robust business case may be created. There is sufficient evidence widespread throughout the UKthat system selection should no longer be subjective but based upon proven performance and provenlongevity.

Best value will be achieved through sound investment in a high-quality overcladding system, wherein thetenants will benefit from a refurbished building that will remain pristine in appearance, requiring nomaintenance, for generations to come. The quality accommodation provided will enhance the communityand ensure long-term demand, increasing the building’s asset value to the Housing Association/LocalAuthority and securing its long-term future.

+ Ke y F e a t u r e s a n d B e n e f i t s

KEY FEATURES AND BENEFITS OF HIGH-QUALITYOVERCLADDINGThe key features and benefits of adopting a high-quality approach to refurbishment are addressed in thefollowing inter-related bullet points:

• LONGEVITY – a high-quality system lasts 2 and 3 timeslonger than mid- and low-quality systems respectively

• APPEARANCE – every overcladding system should remainpristine throughout its life expectancy but it is proven thatlow- and mid-quality systems quickly deteriorate longbefore, appearing dirty and unappealing within a few years.A high-quality system has an in-built water managementsystem, self-cleaning surfaces and no visible face-fixingthereby retaining an attractive, desirable appearancethroughout its 60 year life, withstanding close inspection.Low- and mid-quality systems have no water managementand/or are faced-fixed, resulting in rapid pattern stainingand a sub-standard, undesirable appearance

• LOWEST COST – a high-quality system has the highestinitial capital cost but the greatly extended longevity resultsin the lowest year-on-year and whole-life costs. High-qualitysystems are therefore by far the most economic (up to 2/3rdless) over their lifetime

• PROVEN PERFORMANCE – overcladding has been aroundfor 30 years, consequently the varied performance ofdifferent systems is evident and widespread. Many pastlow-cost overclad projects have already been re-overclad.Those remaining look drab and little better than the originalconstruction. In contrast, there are a number of examples of20+ year-old high-quality systems looking as good as theday they were constructed showing no signs ofdeterioration

• DEMAND – the desirable ‘in-service’ appearance sustainedthroughout the service life of high-quality overcladdingensures high long-term demand for the qualityaccommodation provided

• THERMAL PERFORMANCE – windows are the mostsensitive element determining a building’s thermalperformance (walls can achieve the same U value for eachof the low-to-high-quality systems presently available).High-quality composite integrated windows readily exceedcurrent building regulation standards by up to 30% thusreducing heating energy costs and carbon emissions. Thesame cannot be said of typical uPVC windows installed inlow-to-mid-quality envelope systems. Windows in our 20-year-old high-quality projects still exceed today’s standards

• SINGLE POINT RESPONSIBILITY – this is typically thepreserve of those providing high-quality solutions, whereinsingle point responsibility is taken for all aspects of a projectfrom design through to completion, as opposed to acombination of system suppliers, main contractors andinstallers more usually seen in low-to-mid-quality systems.The single point responsibility is readily extended to includethe repair of the existing structure, its ability to withstandthe imposed loads and its long-term integrity once overclad– this is highly desirable from the purchasing authority’sperspective as each element of existing and new is mutuallydependent upon the other for long-term performance

• WARRANTY – as a consequence of single pointresponsibility, a warranty of 20 years is available for high-quality overcladding compared to manufacturer’s warrantiesof c.10 years for lower-quality systems

• SUSTAINABILITY – high-quality aluminium rainscreen isthe most environmentally sustainable option. It is madefrom 65% recycled aluminium, the balance beingmanufactured from hydro-electric sources. The entirerainscreen is 95% recyclable and re-usable at the end of itsuseful life, thus has by far the lowest environmental impactcompared with lower-quality systems

• LOWEST CARBON COST – the greatly extended lifeexpectancy of a high-quality system versus other optionsmeans that the carbon cost of refurbishment is amortisedover a much longer period resulting in the lowest carboncost

• CONSTRUCTION – a high-quality system is fully-engineeredand manufactured off-site to enable simple, rapidinstallation on-site thereby minimising disruption to tenantsand associated risks to operatives and ensuringpredictability in meeting the required delivery programme

• MAINTENANCE – for high-quality systems there are nogaskets or sealants requiring periodic replacement, thusmaintenance costs are eliminated. Both render and boardsystems require an on-going programme of scheduledmaintenance

• QUALITY-ASSURANCE – aluminium rainscreen panels andhigh-quality windows are designed, sized, specified andfully -fabricated off-site and are quality-assured at the pointof manufacture. This ensures a high-quality finished productwith reduced reliance upon on-site trade skills

• CDM – high-quality overcladding has a life expectancy threetimes that of low-quality overcladding. By adopting a high-quality approach to refurbishment, disruption to occupantsand risks to tenants and operatives is minimised to onceevery 60 years (the life expectancy of a high-quality system)rather than every 20 years (the life expectancy of a low-quality system)

• BEST VALUE – ‘The mission is to deliver the lowest costsolution which meets all the required performance levelsand retains a quality, desirable appearance throughout theanticipated service life of the overcladding system’. This isachieved through sound investment in a high-qualityovercladding system, wherein the tenants will benefit froma refurbished building that will remain pristine inappearance, requiring no maintenance, for generations tocome. The quality accommodation provided will enhancethe community and ensure long-term demand, increasingthe building’s asset value to the Housing Association orLocal Authority and securing its long-term future.

Low- and mid-quality cladding systems quickly deteriorate in appearance longbefore reaching their in-service life expectancy, giving rise to pattern staining anda sub-standard appearance which reflects in low demand for the undesirableaccommodation.

+W h o l e - L i f e C o s t C o m p a r i s o n

0

1

2

3

4

5

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7

8

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59

(£m

)

Years

£1.5mAluminium

£3.3mBoard

£4.6mRender4

£4.6mRReReReRe dndndndnderererer

1

2

3£3.3mBBoBoBoaaarrrdddd

£1.5mAAAAllll1

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INITIAL CAPITAL COST SERVICE LIFE TOTAL CAPITAL (£m) (YEARS) OVER 60 YRS (£m)

Aluminium 1.5 60 1.5

Board 1.2 30 3.3

Render 1.0 20 4.6

Whole-Life Cost Comparison Between Overcladding SystemsEvery overcladding system should remain pristine throughout its life expectancy but it is proven that low- and mid-quality

systems quickly deteriorate long before.

W e s tW h i t l a w b u r n ,G l a s g o w

+ We s t W h i t l a w b u r n , G l a s g o w

REFERENCE CONTACT

Client West Whitlawburn Housing Association/Lovell (MC)

CONTRACT VALUE £2.1m per tower

PROJECT DURATION Phased from 2002 to 2009

PROJECT SCOPE

Design and installation of aluminium rainscreen, curtain walling, balcony

enclosures, replacement windows, steel extension roof and roof cladding to

six occupied tower blocks.

+We s t W h i t l a w b u r n , G l a s g o w

The Business Case for High-Quality Refurbishment


Balconieswereenclosedcreatingadditionalinternallivingspace.

C a s t l e C o u r t ,S h e f f i e l d1991

C a s t l e C o u r t ,S h e f f i e l d2010

+ C a s t l e C o u r t , S h e f f i e l d

PROJECT SCOPEMajor residential scheme to convertempty accommodation into high-qualityapartments. External envelope workscomprised 15,000m2 of aluminiumrainscreen and high-performancereplacement windows.

REFERENCE CONTACT

Mike Hollindale, Area Estate Manager,

Guinness Northern Counties Housing Association

2 Castle Court, St Johns Road,

Sheffield S2 5JX

T: 0114 2591514

CONTRACT VALUE £4.6m

PROJECT DURATION46 weeks (1991)

Client Testimonial

Castle Court provides 1, 2 and 3bedroomed general purpose socialhousing with no restrictions on tenant-type. These flats are very popularbecause they provide high-qualityaccommodation, the site is very securewith extensive CCTV and there is a 24hour, 7 days-a-week concierge service.Castle Court is always fully occupiedand there is a long waiting list for themso when any flats do become vacant wefill them immediately. With the waythe building looks and the quality ofinternal accommodation, tenants arealways very surprised to learn how oldthe building actually is.

Mike HollindaleArea Estate Manager, Guinness Northern

Counties Housing Association

Since refurbishment the building has been fully occupied

throughout and there is a waiting list for the quality accommodation

afforded. The building is pristine in appearance today and has not

required cleaning or maintenance since the new envelope was

installed in 1991. It will remain in this immaculate condition for at

least a further 40 years, thereby ensuring long-term demand and best

value for the building owner.

+C a s t l e C o u r t , S h e f f i e l d

Th e P i n n a c l e ,W i l l e n h a l l

+ T h e P i n n a c l e , W i l l e n h a l l

Development Case Study – The Pinnacle

BackgroundOriginally constructed in 1967 using a large panel system, this 15storey residential tower block is representative of high-rise buildingsof the period. Owned by Walsall Council and named St Mary’sCourt, it provided 87 two bedroomed units for social housing.Situated in the south east corner of the town centre, the high-risebuilding stood alone, flanked to the North and West by the towncentre, to the East by low-rise residential housing and to the Southby small industrial units.

Fully occupied from time of construction until the late 1980’s, thebuilding slipped into decline in the early 1990’s. New low-rise socialhousing was being constructed and occupants were rapidlymigrating to this alternative as the tower by now provided sub-standard, dated and unappealing accommodation. With lack ofdemand and falling occupancy, the building was no longereconomically viable to run and maintain and in 1997 the Councilclosed the building.

As is common in these situations, the building and the immediatevicinity subsequently became subject to urban and social decay withthe consequence that the Council decided to demolish St Mary’sCourt. Financial evaluation of this option determined that the landvalue was no greater than the cost of demolition, therefore theCouncil elected to seek an alternative way forward by selling thebuilding. As the surrounding area had already been earmarked forregeneration, the principal condition of sale was that the purchaserrefurbished the building to a high standard.

Commercial Appraisal and Proposald+b facades’ appraisal of the commercial potential identified that:

• the location on the edge of the town centre was reasonablefrom a development perspective

• the building was structurally sound

• high-rise living is popular if the quality is right - numerous newbuild multi-unit residential building projects were underway andselling off-plan in nearby towns

The proposal to the Council included the following projectaims:

• Provide new build-equivalent homes for re-sale to the openmarket. Previous experience had been gained withrefurbishment of Hyde Park Flats (Castle Court) for GuinnessNorthern Communities Housing Association. They remain fullyoccupied and in pristine condition twenty years later

• Resale would be aided by a 10 year insurance-backed warrantyfrom the UK’s National House Building Council, the independentstandard-setting body whose ‘Buildmark’ warranty covers morethan 80% of new and newly-converted homes built in the UK.NHBC approval would be needed for all works

• High-rise buildings are subject to severe exposure, thereforelongevity and robustness of design and materials and productsused was essential

• The internal arrangement (see floor plan) was dated and wouldneed to be reconfigured to a contemporary layout.

Other Considerations

1. High-quality overcladding

The quality of the refurbishment directly influences the buildcost and also the resale value. A saving of GBP 500,000 inexternal refurbishment cost, equivalent to more than GBP5,000 per unit, could have been achieved if a cheap rendercladding was used. Such an approach would have beeninconsistent with the ‘new-build equivalent ethos’ whichunderpinned the refurbishment / resale project and alsowould not have been acceptable to the NHBC, therefore high-quality aluminium rainscreen was chosen

2. Appearance

Tall buildings benefit aesthetically from penthouses and/orfeature rooftops. These additions also contribute towardsgreater social appeal, adding distinctiveness and desirability toa development. Furthermore, through the addition ofpenthouses, additional space is created at relatively low cost

3. Internal structural modifications

The concrete pre-cast panel internal walls were structural anddid not lend themselves readily to being altered to formcontemporary layouts. In order to generate maximum appealto future occupants, openings would need to be formed andstrengthened in order to achieve open-plan livingaccommodation

4. Facilities improvement

A single bathroom / WC does not fit with modern livingrequirements. The refurbishment plan therefore had toprovide each two bedroomed unit with a bathroom / WCsuite and a shower room / WC suite (see floor plan).

+T h e P i n n a c l e , W i l l e n h a l l

Dated internal layout with separate kitchen / living-room, single

bathroom and no shower facility is inconsistent with modern

living requirements.

Existing Apartment Plan

Refurbished Apartment Plan

Contemporary accommodation post-refurbishment:

• Open-plan living with walk-through kitchen and lounge / diner

• WC / shower room in addition to WC / bathroom

• New-build equivalent specifications

• At the point of building closure, rental income was c. GBP 250 per unitwith 50% occupation

• Building had reached the end of its useful life

• Demolition cost c. GBP 0.5M

• Land asset value post-demolition c. GBP 0.5M, therefore no economicbenefit to demolition

Purchase and Refurbishment Costs:

• Building consisting of 87 flats was purchased for GBP 1M

• Refurbishment cost of GBP 4m in 2005

Economic Benefits:

• Resale value of GBP 7M

• Present rental income GBP 450 per unit

• Present occupation 95%

• Building life extended by 60 years

• Refurbishment underwritten by comprehensive warranty

• Energy consumption per unit reduced from c. GBP 200 per quarter toless than GBP 70 per quarter, saving 70%

• Maintenance costs eliminated

DeliverableObjective

ECONOMIC

SOCIAL

• Building performance equivalent to a new-build

• Low carbon emissions

• The building’s embodied carbon has been preserved

• Refurbishment has used materials which are predominantly (65%)recycled and which are themselves 95% recyclable at the end of theIruseful lives

ENVIRONMENTAL

• Contemporary and aesthetically pleasing

• External surfaces will remain pristine

• Desirable accommodation

• Low unit turnover

• Healthy internal environment

• Preserved and modernised the original design intent

• Good quality of life for tenants

• Has contributed towards local urban regeneration

Project Deliveryd+b facades tender was accepted by Walsall Council in2003. With full co-operation from the Council, aplanning application was quickly submitted andconsent was granted at the same time as purchasecompletion. Building Controls and NHBC designapprovals were also granted. The refurbishmentproject commenced shortly thereafter beginning withstrip-out works in late April 2004.

Project Completion and Analysis

Renamed ‘The Pinnacle’, the building was regeneratedfrom derelict tower block to high-specificationproperty including the addition of 6 new penthouseunits within 50 weeks. It was completed in early April2005 and was opened by the Lord Mayor of Walsall.

This project was undertaken on a commercial basisinvolving complete refurbishment ahead of onwardsale. From the outset, it fully considered and adopted ahigh-quality, whole-life approach, exemplifying all thebenefits of economic, social and environmentalsustainability contained within this document andshowcases what is possible in refurbishment projects.

G r a i s e l e y,W o l v e r h a m p t o n

+ G r a i s e l e y, Wo l v e r h a m p t o n

PROJECT SCOPEDesign and build of an insulated aluminium rainscreenand replacement windows to three 10 storey occupiedresidential tower blocks. Additional works undertakenincluded extensive structural steelwork to extend andenclose balconies to provide increased internalaccommodation and provision of an additional lift tothe exterior of the buildings with a glazed linkseparating this feature from the buildings.

REFERENCE CONTACT

Lisa Green, Principal Renewal Officer

Neighbourhood Renewal (Operations), Regeneration and Environment

Wolverhampton City Council T: 01902 554813

E: [email protected]

TYPE OF CONTRACT Partnering contract with Bullock Construction Ltd


PROJECT DURATION 78 weeks

+G r a i s e l e y, Wo l v e r h a m p t o n

Balcony enclosures created additional internal living space.

Balcony treatments are varied.

A l p h a H o u s e , C o v e n t r y

+ A l p h a H o u s e , C o v e n t r y


PROJECT DURATION46 weeks

Client Testimonial

“We chose d+b facades’ to externally refurbish Alpha House because their proposedsolution was a superior product to all other tenders. We were also strongly influenced bytheir track record of similar projects and experience as developers in their own right. Theproject progressed extremely well and we are delighted with the outcome which provideshigh quality accommodation for our tenants.”

Keith Rounds Head of Planning & Procurement, Whitefriars Housing Group

+A l p h a H o u s e , C o v e n t r y

BackgroundAlpha house, is a square on-plan, multi-unit residential building of 17storeys built in 1962 comprising 97 residential units. It wasconstructed using a Jack-Block system around a central concretestructural core with cantilevered floor plates supporting a non-structural cladding system.

The building is owned by Whitefriars Housing Group, part of WestMercia Housing Group, Coventry’s largest social landlord and one ofthe UK’s most successful social housing associations. The Group is anot-for-profit organisation owning and managing approximately16,500 homes across the city of Coventry.

Planning consent had been granted for a new cladding system in orderto meet thermal insulation performance levels required as part of theDecent Homes Standard 2010. This programme was launched inEngland in 2000 by the Department for Communities and LocalGovernment to improve the conditions of homes for social housingtenants and vulnerable households in non-decent private-sectoraccommodation. The target was for all social housing managed bylocal authorities and Registered Social Landlords to be decent by 2010.

After

Before

d+b facades’ SolutionWith accumulated experience and expertise developed from refurbishing many high-rise,occupied residential buildings, d+b facades quickly identified a number of risks andareas of concern, particularly relating to the requirement for removal of the existingcurtain wall.

An alternative approach was developed and proposed which involved retaining theexisting curtain wall and overcladding the entire building. In this way, critical concernsand risks were designed-out from the original enquiry document (Table 4.). WhitefriarsHousing Group adopted d+b facades’ enhanced solution as being the best to meet theirnear-and long-term project goals.

Impact of Original Enquiry Design d+b facades’ Solution

Complete removal of existing curtainwall means temporary wall required:

• prevents occupants from risk of fall• constructed from within dwelling in

existing living space causingexcessive disruption to occupants

• needs to be weather-tight and ableto satisfy high-rise buildingregulations

• internal wall and floor coveringsrequire protection

Programme schedule is partly dependentupon internal access and co-operationof residents

No water management system, thefacade will thus require regular cleaningand sealing gaskets will require periodicreplacement

Removal of asbestos - health and safetyrisks to occupants and operatives

Comparison Between The Requirements of the Enquiry Design and d+b facades’ Enhanced Solution

Retain existing curtain wall and overclad.New envelope fully constructed fromoutside prior to removal of existingwindows with minimal disruption tooccupants and minimising works insideflats, the building remains weather-tight atall times and retains structural integrity

The new building envelope is constructedforward of the existing building so theprogramme can proceed withoutconstraints of occupation

Innovative water management systemmeans surfaces are self-cleaning,minimising maintenance and retaining as-new appearance

Asbestos is undisturbed and encapsulatedunder new cladding system

The aluminium rainscreen system has beenused successfully in more than 50 projectsand established a proven track record onprojects identical to Alpha House.Timber/aluminium windows are muchstronger than uPVC and require nomaintenance, making them moreappropriate for high-rise dwellings

Proposed replacement compositeuPVC/steel/aluminium curtain wallsystem has no track record of use inhigh-rise projects of this nature anduPVC windows inevitably require anongoing maintenance programmethroughout their useful life

Enquiry DocumentThe enquiry document describing the works to be undertaken specified:

• Removal of the existing steel and glazed curtain walling system and windows

• Installation of a new curtain wall constructed from a composite of uPVC, steel andaluminium, replacement windows and thermal insulation

• Enclosure of the existing open building entrance in keeping with the proposed new claddingsystem

• Safe removal of all asbestos

+ A l p h a H o u s e , C o v e n t r y

Benefits:• Warmer in winter

• Reduced heating costs

• Reduced solar gain in

summer

• Less noise intrusion

• Improved natural

ventilation

• Tilt mechanism permits

windows to be safely

cleaned without leaning-

out

• Residents offered an

individual choice of

internal window finishes

Before After

ENQUIRY DESIGN d+b facades’ REDESIGN

Estimated energy saving of £278 perflat per annum

Estimated carbon emission saving of1.98 tonnes per flat per annum

Components made from uPVC have asignificant environmental footprint,particularly in the manufacturingprocess

Will require regular cleaning andongoing maintenance

Refurbishment life expectancy of up to40 years

Enhanced Solution - Sustainability Improvements

Estimated energy saving of £321per flat per annum

Estimated carbon emission savingof 2.29 tonnes per flat per annum

The aluminium rainscreen iscomposed of 65% recycled materialwhich is 100% recyclable at theend of its useful life. The timberelement of the windows is 100%sustainable

Surfaces are self-cleaning and willremain as-new with no maintenance

Refurbishment life expectancy of60 years. Amortised spendsubstantially lower when based onwhole-life cost

Although the original enquiry design for replacement of the curtain wall and newwindows would have delivered financial, social and economic benefits to the building’sowners and tenants, d+b facades’ enhanced solution delivered even greater benefits forlittle additional cost.

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