WILKES STREET, E1 to mass concrete pad footings/underpinning to be RC32/40 to BS8500. All blinding concrete to be Gen 2 to BS8500. B.S.8110:1997. Nominal cover includes permitted deviation

This Grade II listed building on Wilkes Street is located off Fournier and Princelet Streets in the heart of Spitalfeilds. It is part of a charming set of streets of period houses and enjoys proximity to the facilities of Spitalfields Market and Brick Lane.

The property was rewired and refurbished throughout with new openings created to allow for more light and better movement however the majority of the works took place below ground. Here, major excavation, underpinning, Delta tanking and ground water/soil pump works/installations were required in order to house the movie room, gym, utility room and bathroom.

A key contribution was made by the Sonsino Turcan project management team who offered an alternative drainage system design which reduced the scope of the structural works required. This translated to a £20k reduction of the contract price.

Existing floor area: 3,400 sq. ft.Finished floor area: 3,400 sq. ft.Contract value: £390,000 ex. VATContract duration: 10 months

WILKES STREET, E1 RESIDENTIAL CASE STUDY | LONDON

PROJECT TYPES

Residential and listed buildings

YEAR

CLIENT LOCATION

Spitalfields London

2016/2017

Private

T: +44 (0)207 937 0007 E: [email protected] www.sonsinoturcan.co.uk Sonisino Turcan Limited 13 Prince of Wales Terrace, London, W8 5PG

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WILKES STREET, E1 | SONSINO TURCAN RESIDENTIAL


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Plan on Foundations

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13-13212

Note:The Contractor is required to maintain records,including photographs, of all excavations andunderpinning legs including sequencing andrespective width/depth of legs.

Note:The Contractor is responsible for the locationof any underground services that may existand to divert them if necessary at thecommencement of work. Where drainagepasses underneath slab it is to be encased inconcrete.

Numbering indicates proposed sequenceof underpinning operation. Contractor mayvary sequence with the permission of theEngineer and to the satisfaction of theLocal Authority.

Note:The Contractor is to allow for all necessaryCCTV Survey investigation to establish natureand extent of existing drainage system.

Note:Any existing poor quality concrete to be removedprior to underpinning wall.

Existing walls to be underpinned with massconcrete stem and RC base, Grade C32/40to allow construction of reduced levelstructural slab. Refer to relevant sectionsand Ward Cole Specification for TraditionalUnderpinning. Phase 1a

3150 site dim3no. equal pins

Note:All dimensions, concrete / steelworksetting out and levels to beobtained/checked against Architectsdrawings and by site measurementprior to commencement of work orordering of materials.

Note:Refer to Contractor / Mechanical andElectrical engineer for details of SubStructure drainage and service entry/ route positions.

Note:The Contractor is responsible for all temporaryworks associated with the proposed works andis to submit full method statement, sequencing,drawings and calculations to Ward Cole forreview prior to the commencement of the works.

Note:All DPC's, DPM's, Cavity drainageand waterproofing details to be inaccordance with the contractorsdrawings and specifications

2600 approx3no. equal pins

1000

1500

= =

1200 1200935site dim


1000

1500 2350 approx

10003000

900site dim

3no. equal pins

1500

==

2700 approx

3no. pins @ 900

1500

1700

1350

3300 site dim



3no. equal pins

Existing concretefooting to be retained

New RC wall 220thk and 585 dp RC basecast in 1.0 m lengths. Refer to relevantsections and Ward Cole Specification forTraditional Underpinning. Phase 1c

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5 2 6 4

6 4

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Existing external walls tobe demolished. Refer tosuggested sequence ofoperations adjacent.

Sequence Of Operations

Phase 1a - Underpin existing cellar walls asindicated, to achieve reduced basementfloor level to maximize headroom.

Phase 1b - Installation of new steel beamsto support walls at ground floor level.Note: Wall to be temporarily laterallypropped at basement level

Phase 1c -Install RC wall/underpinning toto allow excavation to extend existingbasement at reduced level to rear ofproperty.

Phase 1d - Demolish walls

Note:All new internal partitions/walls tobe lightweight non load bearingconstruction to Architects detailsand specification.

Indicates extent ofbasement to No. 2Wilkes Street

4

1500

7 9 8 7 9 8 7 9 8 7 9 8

7 9 8

8-8211

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3no. equal pins

1500

1500

12001200

New wall to line up withexisting masonry wall.

site dim

1870site dim

620

1235site dim

220

200

220

= =

Note:Underpinning to lightwells to be confirmedfollowing exploratory excavations toconfirm lightwell footing geometry afterdemolishing wall below windows.

200

220

200

rev. date Description Chk.Drawn

COPYRIGHT © THE CONTENTS OF THIS DRAWING MAY NOTBE REPRODUCED IN WHOLE OR IN PART WITHOUT THEWRITTEN PERMISSION OF WARDCOLE LTD.

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A B DC E F G H J K

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F G H J K

_ Issued for Approval04.03.2016

revision:

scale: status:

job number: drawing number:

drawing title:

project:

tel 020 7494 3224 fax 020 3137 3947

consulting engineers

Winchester House

client:

COLEWARD

e-mail [email protected]

NOTTINGHAMLINCOLN LONDON

London NW1 5RA

259-269 Old Marylebone Road

Eleanor Cowan

Proposed Structural Alterations at6, Wilkes StreetLondon E1 6QF

Proposed UnderpinningFoundation Plan

1:50 Construction

37-259 200 F

KT GMW

GENERAL NOTES

1. This drawing is to be read in conjunction with all relevantArchitects and Engineers drawings and Specifications.

2. All dimensions to be obtained/checked against Architectsdrawings and by site measurement prior to the commencement ofworks or ordering of materials.

3. Where discrepancy occurs between specification and drawingthe Engineer must be notified.

4. The Contractor is responsible for the overall stability of thestructure from the commencement of work, including the designand provision of all necessary temporary works. The Contractor isto submit full details of his temporary works proposals to theEngineer for his consideration at least two full weeks prior to thecommencement of works.

5. All DPMs, DPCs, waterproofing and weathering details to be inaccordance with Architects details.

6. All concrete to reinforced elements to be RC32/40 to BS8500. Allconcrete to mass concrete pad footings/underpinning to beRC32/40 to BS8500. All blinding concrete to be Gen 2 to BS8500.All concrete to be placed and compacted in accordance withB.S.8110:1997.Nominal cover includes permitted deviation of 10mm U.N.O. inaccordance with BS8500.Mass concrete padstones and tie bars to be Grade C30 with 10mmmax. size of aggregate.

7. Concrete dry pack to consist of 3:1 sharp sand : OPC, with onlysufficient water to bind together the mix when well rammed intoplace. Ensuring full load transfer.

8. All steelwork to be Grade S355 and to comply with BS 5950.Steelwork which is not to be cased in concrete is to be suppliedshot blasted to SA2½ then coated with 1no. coat high build zincphosphate modified alkyd paint, minimum DFT 75 micrometerstouched up on site after erection as required.Steelwork within cavity or encased in masonry is to receive anadditional 2no. coats of site applied bituminous paint, minimum DFT100 micrometers.Steelwork which is to be cased in concrete is to be supplied freefrom mill scale and rust and is to remain unpainted.All external exposed steelwork shall be galvanized. Surfacepreparation by blast cleaning to BS 7079-A1, to preparation gradeSa2½, using chilled angular iron grit grade G24 to give a coarsesurface profile, followed by chemical cleaning. Galvanizing shall beto BS EN ISO 1461 with a minimum mean coating thickness of 140micrometers.

9. All steelwork and fixings are to be adequately protected againstfire to the satisfaction of the Local Authority and in accordance withArchitects details and specifications.

10. All bolts and washers to be mild steel. All bolts to be Grade 8.8unless noted otherwise. All welds to be continuous 6mm fillet weldsunless noted otherwise.

11. The Steelwork Fabricator is to submit full working fabricationdrawings to the Engineer at least two full weeks prior to fabrication.

12. All steelwork connections to be cleated and bolted fixings inaccordance with design prepared by Steelwork Fabricator. Figuresshown thus (99) at beam ends are beam reactions in kN, for whichthe relevant connections are to be designed.Use min. 4no. M16 Grade 8.8 bolts per connection.

13. All new timber to be Grade C24. Timber is to be preservativetreated in accordance with Architects specification, with cut endsthoroughly treated prior to building in.Materials and workmanship to be in accordance with BS 5268.

14. Any soft spots encountered under foundations to be removedand replaced with mass concrete.

15. Setting out of new walls to be in accordance with latest relevantArchitects drawings.

16. Where any delay occurs in the placing of concrete, a 50mm layerof blinding concrete is to be placed as soon as possible afterexcavation and exposure of formation level.

17. All foundations to be cast at an approved formation level to thesatisfaction of the Local Authority.New foundations have been designed for an allowable nett groundbearing pressure of 150kN/m2. This must be agreed with the LocalAuthority prior to the commencement of work or ordering ofmaterials.

18. Under slab granular material is to consist of selected brokenstone, concrete, brick or other approved material free of any organicand deleterious material, and to be chemically inert. The material isto be max. 75mm gauge with sufficient fines to ensure thoroughcompaction in 150mm deep layers.Any soft spots encountered under slab to be removed and replacedwith granular material.Depth of under slab fill must not exceed 600mm, laid in 150mm deeplayers.

19. The Contractor is responsible for the location of any existingservices that may exist on site, and to divert them as necessary priorto the commencement of work.

20. All blockwork used below ground level is to be of foundationquality with the relevant British Board of Agreement Certificates.

21. This scheme assumes a min. compressive strength of existingbrickwork to be 15N/mm2 in mortar designation IV. This is to beagreed with the Local Authority prior to the commencement of works.

22. All structural works are to be carried out strictly in accordancewith the details given by Ward Cole. The Engineer is to be advisedof any significant variation prior to its implementation.

23. Where padstones or spreader beams are cut into existingbrickwork, care is to be taken to ensure that only the minimum ofdisturbance is caused. Padstones and spreader beams are to beplaced on a leveling bed of mortar and to be fully shimmed and drypacked over to ensure full load transfer.

24. Where new steel beams bear onto mass concrete padstonesprovide 2no M12 cast in rag bolts.

25. All existing timber structure being retained is to be checked foradequacy and condition to the satisfaction of the Local Authority.

26. High yield steel prefixed 'H' on drawing and delivery tags, to be inaccordance with BS 4449:2005. Mild steel prefixed 'R' on drawingand delivery tags to be in accordance with BS 4482:2005. Cuttingand bending of reinforcement is to be accordance with BS8666:2005.High yield mesh fabric to be in accordance with BS 4483:2005.All reinforcement to be adequately restrained, positioned andsupported on suitable chairs and spacers to achieve the requiredcover in accordance with BS 7973.

27. Where new steelwork beams are provided to support existingstructure over, the Contractor is to provide shims and dry packingbetween new and existing structure to ensure full load transfer.

28. All new brickwork to have a min crushing strength of 20.0N/mm²water absorption 7-12%, all blockwork to be 7.3N/mm² to complywith special category of manufacture as laid down in BS 5628 laid inmortar designation (iii) - unless noted otherwise

29. All finishes to be to Architects details and specification.

Specification of Traditional Underpinning

1.00 Codes of Practice

All continuous underpinning is to be carried out strictly in accordancewith the requirements of B.S.8004, 1985. The Code of Practice forFoundations. All materials used in the works shall comply with therequirements of the relevant Codes of Practice.

2.00 Shoring and Propping

It is the Contractor's responsibility to take all necessary steps toensure that the structure is adequately propped, shored and bracedto ensure that during the progress of the works excessive deflectionsor deformations of the structure do not occur.The Contractor shall discuss with the Engineer any proposals fortemporary works. This does not in any way relieve the Contractor ofhis responsibly to ensure that the structure is adequately supportedat all times during the progress of the works.It is frequently necessary for the Contractor to brace or prop existingopenings so that isolated load bearing piers may be underpinned.The Contractor is to allow in his tender price for all propping, shoringand bracing required to ensure that the works may be safelyundertaken with no undue disruption to the structure.Where temporary propping is necessary to facilitate dismantling andreconstruction of load bearing elements the contractor shall preparea method statement, which shall be subject to the approval of Ward+ Cole

3.00 Sequence of Working

The sequence of working is to be submitted to the Engineer andapproved by the Local Authority. This shall be based on a maximumbay length of approximately 1.0m.The agreed sequence of operations shall be strictly adhered to. TheContractor may wish to alter the excavation and concretingsequence, but this must be discussed with the Engineer/LocalAuthority Representative, and no deviation from the sequence ofoperations shall be permitted unless the Engineer/Local AuthorityRepresentative confirms otherwise in writing.The underpinning works shall be carried out strictly in the followingsequence:-

a. Excavate legs No. 1. These are to be inspected and approvedby the Local Authority Building Inspector and Ward + Cole to ensurethat the conditions are consistent with the site investigation data.

b. On approval of leg No.1 excavations, insert dowel bars, cleanoff the underside of the existing footing. Obtain approval to concrete,ensuring concrete is well vibrated to give adequate compaction.Allow concrete to harden for a minimum of 24 hours.

c. Dry pack 75mm to ensure complete load transfer Allow toharden for a minimum of 24 hours.

d. Repeat stages b and c for legs No. 2 and so on.

7.00 Concreting

All concrete shall be grade RC30 with min OPC content of 300kg/m³³3 and a nominal aggregate size of 20mm, and mixed, delivered,placed and vibrated strictly in accordance with the concretespecification contained in B.S.8110:Part 1:1985. Sulphate resistingcement to be used should site conditions dictate or as directed byLocal Building Control Officer.It should be noted that the concrete should be adequatelycompacted with a vibratory poker to ensure adequate density.The concrete for the underpinning legs should be brought up to75mm from the underside of the existing footings.

8.00 Dry packing

Once the concrete in the underpinning legs has set (at least 48hours after concrete placement) the gap between the underside ofthe existing footing and the top of the new footing is to be packedwith dry concrete.The mix proportions for the dry concrete are to be weight 1:3(cement:zone 2 sharp sand) with Combex admixture added inaccordance with Manufacturers recommendations. The constituentsare to be mixed dry and a small volume of water is to be added suchthat when compressed, a small ball of mixture retains its shape.The dry packing concrete is then to be rammed solid into the gapbetween the underside of the existing footing and the top of the newfooting using a steel bar.

9.00 Curing time

A sufficient time should elapse between the completion of drypacking and the excavation of any underpinning legs in the vicinity.The curing time shall be agreed with the Engineer, this beingdependent upon the prevailing weather conditions.Vicinity in this context shall be deemed to include all legs adjacentto, or next but one to the leg in question.

10.00 Provision for existing services

Underpinning legs may be punctured by the services entering thebuilding. The means of "sleeving" these services shall be agreedwith the Engineer during the progress of the works.Where existing services interfere with or affect the underpinningexcavation these should be temporarily diverted.The Contractor shall make due allowances in his tender price for anydiversions of services, sleeving or other service adjustments whichmay be required in order to undertake the works in satisfactoryfashion.

4.00 Excavation and Approval

During excavation the Contractor shall take all necessary steps toprevent softening of the excavation base by ground water. Wherenecessary the Contractor shall keep excavations free from groundwater by pumping.The Contractor shall also ensure that the base of the excavationshall not become contaminated by loose material falling into theexcavation.

The Contractor shall take steps to ensure that the size of theexcavation closely matches the required size agreed with theEngineer/Local Authority Representative. Excessive overbreak willnot be permitted, and the Contractor shall provide all necessarytrench sheeting and strutting to prevent overbreak.The Contractor may be required to provide sheeting and strutting toprevent any ingress of loose material from beneath the existing slab.All underpinning excavations shall be approved by the LocalAuthority Representative before any concrete is placed.

5.00 Linking of adjacent bays

Prior to concreting the Contractor shall incorporate dowel bars topermit shear transfer between adjacent underpinning bays. Allunderpinning legs shall be linked to adjacent legs by driving 4 No.H20 dowel bars, 600mm long into adjacent ground. Penetration ofbars to be 300mm into adjoining legs. Minimum cover to all dowelbars to be 100mm. Projecting dowel bars should be cleaned of allloose dirt prior to concreting.

6.00 Cleaning of existing footings

The underside of all existing footings (where exposed by excavationin preparation for underpinning) shall be cleaned of all loose soil andfragments.Any major projections or inclusions such as bricks, broken concreteor boulders, shall be broken away from the underside of the existingfootings. Prior to concreting the underpinning leg the existingfootings should be clean, firm and level so that dry packing may beaccomplished satisfactorily.

A Extent of basement indicated. Underpinning revised11.03.2016 KT GMWB Underpinning adjusted to suit drainage sumps12.04.2016 KT GMWC Issued for Construction18.04.2016 KT GMW

D Minor amendments to underpin dimensions for06.05.2016 KT GMWParty wall award

E Lightwell underpinning note added. Sump to pump18.05.2016 SS GMWchambers removed and deeper underpinning removed to suit.

F Retaining wall setting out adjusted16.06.2016 KT GMW

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T: +44 (0)207 937 0007 E: [email protected] www.sonsinoturcan.co.uk Sonisino Turcan 13 Prince of Wales Terrace, London, W8 5PG

Documents

WILKES STREET, E1 to mass concrete pad footings/underpinning to be RC32/40 to BS8500. All blinding concrete to be Gen 2 to BS8500. B.S.8110:1997. Nominal cover includes permitted deviation