clements court, hounslow · success to rectify defective cladding. hounslow prudently over-...

CLEMENTS COURT, HOUNSLOW

De-Clad : 10 days Re-Clad : 18 weeks

Clements Court 23rd June LBHbecome aware of fire hazard.

Clements Court combustible ACM

cladding removed within 10 days.

Clements Court 27th Octoberdefective overcladding stripped

and replaced.

FIRE HAZARDIDENTIFIED

BUILDINGRECLAD ANDNORMAL LIFE

RESUMES

23JUNE

COMBUSTIBLE ACM CLADDING REMOVED

London Borough of Hounslow (LBH) moved swiftly toidentify, procure and appoint a design + buildovercladding specialist with a proven track record ofsuccess to rectify defective cladding. Hounslowprudently over- specified their requirements to surpasscurrent fire regulations and then closely monitored thespecialist throughout the design and constructionphases. The result, an end product with indefinitelongevity delivered on time and within budget.

An exemplar process ensuring best value with clearroles, responsibilities and recourse for fit-for-purpose.

27OCT

4JULY

2017

2017

2017

C l e m e n t s C o u r t H o u n s l o w D e - C l a d : 1 0 d a y s , R e - C l a d : 1 8 w e e k s

Sustainable regeneration isonly achieved by investingcarefully today to meet theneeds of future generations.

Foreword

The scale of combustible overcladding failures bears

testimony to the fact that overcladding is a high-risk and

complex process – it is very easy to get wrong!

Overcladding failuresextend well beyondcombustible ACM toinclude delaminatingcomposite panels andfailed external wallinsulation (EWI). In suchevent, limited period,caveated warrantiesseldom provide ownerswith recourse (buyer beware; apparent product warranties are often onlydisguised paint warranties).

This is not sustainable. The nation cannot afford to get things wrong on thisscale. We cannot afford it financially and we cannot afford itenvironmentally.

Sustainable regeneration is only achieved by investing carefully to meet theneeds of future generations, yet we are struggling to meet the needs of ourown generation.

Overcladding can be designed to last 100 years, to meet all aspirations andprovide desirable accommodation. This claim is readily endorsed byreference to the oldest successful project comparables (c. 30 years old).

Owners can be assured of delivering sustainable regeneration and avoidingfailure whilst also having clear recourse in the unlikely event it’s required.

Comparables are readily used to verify both product (including fireperformance) and the installation service. We have empirical evidenceavailable and buyers must rely upon it for reference.

We advocate design and build forms of contract and fully support thetraditional Building Control mechanisms that provide us with a welcomesafety net whilst not absolving us of our responsibilities.

Central Government advising which products are suitable for replacing thefailed cladding further compounds and dilutes the responsibility from theindustry where it should firmly reside.

We would like to thank the London Borough of Hounslow for their forwardthinking and our employment on this project.

Click here to viewcladding failure video

The London Borough of Hounslowidentified a ‘Design Build’ form ofContract as the correctmechanism which would result inclear responsibility and culpabilitybeing vested solely in thespecialist contractor.

The combustible claddingwas removed within 10 days.

Summary

The London Borough of Hounslow (LBH) identified

Clements Court cladding as sub-standard and swiftly set

about making the façade fire-safe.

They initially took reference for, and sought advice from, the wide variety ofindustry sources available to them. They quickly agreed terms with d+bfacades on a cost-plus basis to strip the offending cladding and make thefaçade fire-safe.

As the works to remove the combustible cladding progressed, LBH began todevelop their Employer’s Requirements for the making-good works. LBHrecognised that there was no clear path of responsibility for the originalcladding failure and they did not want to make the same mistake again.They identified a ‘Design Build’ Form of Contract that would result in clearresponsibility vested in the Contractor. The Contractor would need todemonstrate a long, proven track record of performance on comparableprojects. The design of the complete new façade system (fixings, supportstructure, insulation, firebreaks, cladding etc) had to be fully certified andwarranted by an industry-leading structural engineer. The cladding systemwas to be non-combustible, it had to meet and surpass ApprovedDocument B standards, be very long lasting with clear, concise andextended warranties. Limited-period and caveated product warranties werenot acceptable. Planning and Building Control approvals were to beobtained. A competitive, fixed, lump-sum price was required and the workshad to be completed within a strict timetable.

Employers Requirements established, LBH invited Contractors Proposal’s.Following careful, weighted assessment of offer(s) received they appointedd+b facades and then closely scrutinised their every action throughout everystage of the design and installation process.

The result is an exemplar project, with clear responsibilities, delivered ontime and within budget. The cladding is sustainable and will meet the needsof many generations to come.


BackgroundClements Court, Hounslow, is a 13-storey residential tower blockcontaining 78 flats owned by LondonBorough of Hounslow. It is typical ofmany tower blocks built in the 1960’sand was overclad by the originalcontractor in 2007 to improve itsappearance and thermal performance.

Following the Grenfell Tower tragedy,building owners across the UK weredirected by central Government to checkand test the cladding on all buildingsincluding residential towers, hospitals,schools, commercial buildings and thosewithin the HE/FE estate. The LondonBorough of Hounslow identifiedClements Court as being at risk, clad incombustible ACM similar to that used onGrenfell Tower. The Council made thedecision to remove the cladding as amatter of urgency.

d+b facades, one of the UK’s leadingdesign build overcladding specialists, wasapproached by the Council.

The need for action was urgent for thesafety of the tenants. Following initialdialogue, and within 48 hours, theparties agreed to move forward toremove the combustible cladding.

Combustible panel removal.


CommercialArrangementsIt was agreed that costs for the works ofmaking the façade fire-safe would be onan open-book, cost-plus basis, providingthe Council with assurance that they werepaying only for the works undertaken.Critically, the works would be undertakenwith d+b facades acting in a maincontractor capacity and being singularlyresponsible for the works with LBH closelymonitoring the works throughout.

13 storey building envelope was removedin just 10 days, leaving the façade fire-safe for a very competitive cost, atestament to collaborative working.

With the immediate danger to residentsnow removed, focus turned towards howbest to achieve the economical andproper reinstatement of the cladding.

All procurement and design options wereconsidered by LBH, material specificationswere carefully reviewed together withsamples. Despite the extreme nervousnessof the entire industry LBH calmly set outtheir Employer’s Requirements (ERs) forthe making-good works. They required anexperienced contractor and structuralengineer to provide a Design Build service,to be singularly responsible for themaking-good and the subsequentwarranting of the whole of the workswhich were specified to surpass currentfire regulations using A1 non-combustiblecladding. All of this was to be supplied fora fixed, lump-sum price including allprelims, access, fixings, support structure,firebreaks, insulation and cladding.

LBH invited tenders which were tocomprise a full set of Contractor’sProposals (CPs), including a pricedanalyses bill, drawings, specifications,programme, warranties, methodstatements and risk assessments.

Following careful and weightedassessment of the CPs, comparison withknown market rates, construction indicesand costs for the original works to ensurevalue for money, LBH appointed d+bfacades who then set about therecladding.

The result was that the combustible cladding was removed within 10 days.


DefectsAs the combustible panels wereremoved the underlying constructionrevealed many defects. LBH, Curtins(structural engineers) and d+b facadesundertook close inspection, testingand documenting of the originalinstallation including primary anchors,cladding support structure, insulationand firebreaks. Defects included:

• Isolated support structurecomponents and fixings weremissing

• insulation was missing and/orinsufficient and/or incorrectly fixed

• firebreaks were installed in thewrong positions and/or installedwith gaps and/or insufficientlapping joints.

. Combustible panel removal uncovers theinsulation and firebreaks.

Incorrectly installed firebreaks.

Incorrectly installed firebreaks and gapsin insulation.

Gaps in insulation and support structuremissing.

Insufficient fixings in insulation. Missing support structure fixings.


RectificationsCurtins, d+b facades’ structural engineeringpartners, directed site activities whichincluded the removal of all insulation andfirebreaks so that the underlying fabric andfixings could be clearly inspected and tested.These elements were deficient in any eventand sent for recycling. Detailed surveys andin situ testing were then carried out of boththe existing fabric and existing claddingsupport structure.

Defects were recorded within acomprehensive QA file. Curtins then setabout desk top re-design of the entiresystem from 1st principals to prove thedesign and specify remedial works includingadditional supports and fixings wherenecessary. LBH closely monitored this processand witnessed in situ testing. Once thesupport structure remedial works werecomplete a thorough QA inspection wascarried out and the works allowed toprogress to the next stage. New firebreakswere installed at maximum 3m centres andaround the perimeter of each opening tosurpass Approved Document B. These werethen QA inspected and signed-off prior tocommencing the next stage of infilling withinsulation. Insulation QA inspected andsigned-off, the recladding was allowed tocommence. This controlled process allowedthe end product to be covered by a Curtinsnew-build-equivalent collateral designwarranty.

The Tenant’s PerspectiveBy adopting a phased procurement and adesign build approach the Council were ableto rapidly mobilise to remove thecombustible cladding by:

• Installing lightweight unobtrusive mastclimbers around the building which posedno security risk to residents’ and wereoperational within seven days ofcommencing works

• No requirement to enter tenants’properties throughout the entire process

• Minimal noise disturbance using diamonddrilling techniques limited to restrictedhours

• No restrictions to the use of kitchenswhilst flue extracts werereplaced/renewed

• Clear access/egress maintained via a fireprotected tunnel whilst the works wereunderway.

Closeup of new firebreak & insulation. Non combustible Flue panel installed.

Window and POD before clean andcladding replacement.

Window and POD clean after newcladding installed.

Support structure replaced where missing.


Re-claddingThe making-good requirements wereconsidered from the outset, for exampleaccess was established which addressedboth the requirements of the strippingworks and those of the making-goodworks, thus preventing any need foradaptations and allowing an almostimmediate site start following d+bfacades appointment for the recladding.

The LBH Employer’s Requirements (ER’s)were onerous though not unreasonablegiven the exceptional circumstances. d+bfacades relish a challenge and workingfor a client able and willing to makeinformed decisions quickly is rare andmakes all things possible. d+b facadessubmitted Contractor’s Proposals (CP’s)by way of offer to the Council and thenat each stage of the works providedprototype samples for inspection andapproval by the client in time to meet theoff-site manufacturing programme whichwould ensure the works on-site could becarried out quickly and efficiently.

The replacement cladding panels aresolid, non-combustible aluminium.Because they are not composite there isno possibility or risk of delamination, thepanels will last indefinitely and caneventually be recoated in situ ifnecessary. Should the cladding no longerbe required it will be recycled. Thesolution is faced-fixed unlike our cassettesystem and lacks the water managementwhich prevents pattern staining but it isentirely fit-for-purpose and representsgood value, meeting sustainabilityaspirations.

LBH Building Control Departmentrequested the fire breaks andcompartmentalisation which prevent thespread of flame behind the cladding tobe upgraded to a level in advance ofpresent regulations thereby future-proofing the installation against thepossibility of more stringent regulationsbeing introduced in the future.

As with any complex project there wereproblems to be overcome and constraintsto be operated within, examples of thisbeing the boiler flues and the fact thatClements Court is an occupied building.d+b facades had to devise safe methodsof working to allow the safe removal ofexisting panels surrounding boiler fluesand their subsequent replacement with

Access under removal.

new non-combustible panels whilstavoiding the need to enter residents’properties and isolate boilers. Byworking closely together with the Clientteam, all challenges were overcome andissues resolved with minimal impact.

Each stage of the recladding processwas subject to careful inspection at pre-determined rigorous inspection hold

points to ensure that everything was100% perfect with every aspect of thenew installation.

The whole process took just 18 weeks with the project beingcompleted on time, on budget andwith minimal disruption to residentswithout the need to decant.


Non combustible cladding complete to surpass current standards.

L to R: Mark Loach, Fiona Twycross, Phillip Morton, Cllr Steve Curran, Mark Malcherek.

Cllr Steve Curran (Council Leader) securing the last non-combustible panel.

L to R: Peter Matthew (LBH Director of Housing),Lourdes DeBarry (Deputy Director of Housing LBH),Fiona Twycross (GLA), Alan Cochrane (Project Manager)and Rob Potter (LBH Investment Manager).

L to R: Phillip Morton, Mark Malcherek, Mark Loach,Cllr Steve Curran (Council Leader), Fiona Twycross(GLA), Mary Harpley (Chief Exec LBH).

Fiona Tycross and Steven Curran thank the residents fortheir patience.

Completion Ceremony


clements court, hounslow · success to rectify defective cladding. hounslow prudently over-...

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