Brief for Window Renewal

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					Brief for Window Renewal
Sustainable Construction - Major Repairs Allowance

This document was last reviewed and revised March 2005

By Ellis and Moore Consulting Engineers

In collaboration with

Venner Lucas Architects
Jon Broome Architects

The briefs in this series are:
• Sustainable Housing – this is a useful background brief for sustainability in this context generally
• Concrete and Structural Repairs
• Roof Renewal
• Security and Safety
• Landscape
• Central Heating
• Window Renewal

An outline Table of Recommended Materials is also available

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Scope and Contents
1      Introduction
2      Condition Survey
3      Resident Consultation
4      Standards
5      Design Considerations
   5.1 Environmental Impact
   5.2 Materials
   5.3 Paint for Timber Windows
   5.4 Glazing
   5.5 General Comments
   5.6 Ventilation
   5.7 Noise
   5.8 Ironmongery
   5.9 Safety
   5.10 Accessibility
   5.11 Security
   5.12 Cleaning
   5.13 Sealing
6      Maintenance
7      Demonstration of Windows
8      Fixing of New Windows
9      Internal Decoration Condition
10     Scaffolding
11     Inspection Guarantees
12     Notes & Glossary

1         Introduction
1.1       Lambeth has a statutory duty to reduce fuel poverty and consultants should design to meet or
          exceed the performance standards of the Building Regulations (Part L) to achieve this.

1.2       Replacement windows must provide a 30-year minimum life and provide increased energy
          efficiency through improved thermal performance, increased security and increased noise
          insulation. New windows shall be easy and safe to operate and clean, and shall be as maintenance
          free as possible.

1.3       The proposed works shall not exacerbate any underlying problems existing in the building.

1.4       Cost will be an important consideration. Options will be weighed both in terms of the initial Capital
          outlay and the ongoing maintenance costs in order that the most cost-effective solution can be

1.5       Aesthetics will also be an important consideration and an agreement will have to be reached with
          the Client in situations where the most cost-effective solution is considered inappropriate to the
          architectural style of the building, and the Planning Department for Planning Approval as a material

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2         Condition Survey
2.1       A thorough survey shall be carried out before commencement of any works in order to establish the
          main cause of the problem and what structural conditions exists and to recommend the appropriate
          solutions i.e. total / partial replacement, repairs or upgrading.

2.2       The outcome of this survey and any recommendations shall be discussed and agreed with the
          Project Team.

3         Resident Consultation
3.1       Resident consultation is essential and must follow Housing Services best practice guidelines. The
          Principal Contractor will be required to submit a Method Statement indicating how resident issues
          will be dealt with once the project is on site.

4         Standards
4.1       All works shall conform to all relevant British Standards and Building Regulations. Full
          consideration must be given to recent performance criteria as published by the relevant
          Government Agencies and professional associations. Energy saving materials and design must be

4.2       The materials chosen shall be of good quality and workmanship and conform to BS 8000
          workmanship on building sites.

          Code of practice for working in occupied dwellings

4.3       This sets out the minimum standards as required by the Client. The 'Code of Practice for Protection
          of the Public/Residents during contract works to Lambeth Housing Land or property', is applicable
          to all contractors working on Lambeth's Housing Services land and property should be complied
          with. Detailed consideration should be given to the programming of works in order not to
          inconvenience residents unduly.

5         Design Considerations
5.1       Environmental impact

5.1.1     Lambeth Housing must fully consider its role as environmental steward, and intends to review the
          present reliance on PVC-U window replacement on capital projects. PVC-U has a significant
          environmental footprint, particularly in the manufacturing process, and possibly after final disposal.
          Present assumptions that PVC-U windows require minimum maintenance and offer better value for
          money need to be coherently reviewed.

5.1.2     Softwood high performance windows perform best in respect of design considerations based on an
          environmental impact assessment that considers initial cost, maintenance cost, performance
          issues, embodied energy & recycling potential of window units. The recommendations below
          however reflect cost constraints in the context of Lambeth’s Capital Programme of works.

5.2       Materials

          Please refer to the ‘Brief for Sustainable Housing’ and the ‘Recommended Materials Table’
          for fuller discussion of the environmental and sustainability issues involved in material

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5.2.1     When specifying window frame material each project should be reviewed on a case-by-case basis,
          with serious consideration being given to specifying high-performance sustainably sourced
          softwood windows, especially for low-rise projects.

5.2.2     Cost analysis indicates that high performance sustainably sourced timber windows are
          approximately 20% more expensive than PVC-U windows. This brief therefore reluctantly accepts
          the continued use of PVC-U windows (except in Conservation Areas) if unavoidable. The BRE is
          reviewing lifecycle implications of PVC-U in building products. Lambeth Housing will further review
          the issues once this comprehensive cost analysis of maintenance issues, and guidance on lifecycle
          analysis of material selection becomes available.

5.2.3     PVC-U is more difficult to repair than timber, can become brittle with age and become discoloured,
          and should have maintenance cycles as with timber windows. A September 2000 report by the
          Department for Environment Food and Rural Affairs (DEFRA) compared PVC windows with timber
          and found that over thirty years:
•         PVC windows consume more total primary energy,
•         PVC windows emit biomass CO2 whereas timber emits and consumes CO2
•         Timber windows perform better for fossil emissions
•         PVC emissions are 10% higher for oxides of nitrogens
•         PVC emits double the sulphur emissions of timber
•         Timber windows generate 43% less waste than PVC windows
          For further information see or consult a member of
          Lambeth’s Environmental Development Team on 020 7926 3572.

5.2.4     Further EC directives regarding which materials are prohibited from landfill (where there are
          environment and / or health issues) will be forthcoming. This could include PVC-U products. Landfill
          costs will increase over the next few years. Social landlords may therefore face prohibitive costs in
          future disposal of PVC-U products.

5.2.5     Timber/aluminium composite or thermally broken aluminium windows may be more appropriate for
          high-rise dwellings where zero maintenance is required.

5.2.6     The specifics of a given project will require dialogue between consultant, client and residents. The
          Environmental Development Team in Housing Regeneration Services is most willing to discuss any
          issues that arise.

          PVC-U Windows - Setting Quality Standards

5.2.7     There are numerous British Standards that reflect best practice in setting performance
          requirements for PVC-U windows. However some of these are graded standards and simple
          reference to them is inappropriate. Some are under revision and the publication of European
          standards will lead to the withdrawal of British standards. To obtain adequate quality standards
          LHC bulk arrangements should be specified as quality standards are implicit within this process.
          LHC (previously London Housing Consortium) is a major procurer of PVC-U windows for Local
          Authorities and Housing Associations. Lambeth is an Associate member of the LHC. The service is
          free of charge to specifiers in Local Authorities. Regeneration Services has full details of LHC
          arrangements or you can contact them direct on 0208 561 4700.

          Timber Windows

5.2.8     In conservation areas, windows should ideally be repaired or refurbished. If replacement is
          required, it should reflect guidance agreed between Lambeth Housing and Lambeth Planning*.

5.2.9     Where used, windows to be high performance softwood windows to comply with BS 644, double
          vacuum impregnated and fully factory-finished in microporous paint. (See also the Brief for
          Sustainable Housing). Windows to have aluminium bottom beads & cill extensions. Projecting
          timber cills are not to be specified.

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5.2.10 All timber must be FSC certified (or equivalent), as Lambeth Housing’s Sustainable Timber
       Procurement Policy. Please refer to this and the accompanying Procedure Note for Consultants for
       full information.

5.3       Paint for Timber Windows

5.3.1     Windows to be fully factory finished in microporous paint. Where site finish is necessary, use high
          solid alkyd paint which contains less organic hydrocarbon solvents or consider specifying low
          environmental impact natural paints and stains which cost more but which are substantially less
          damaging to the environment. Avoid normal alkyd paint.

5.4       Glazing

5.4.1     Glazing should be 28mm sealed double glazed unit with low emissivity (LE) coatings/glass (this is
          assumed in the Building Regulations to meet the required U-value of 2.0/2.2 W/m2C°). Savings in
          energy costs will repay the extra initial cost of LE glazing within its lifetime. Argon filled LE double-
          glazing should be considered in order to further improve performance and make further energy

5.5       General comments

5.5.1     Where new windows are being installed consideration should be given on how to provide for

5.5.2     All glazed areas should be easy to repair and maintain and clean from within the dwelling.

5.6       Ventilation

5.6.1     Adequate ventilation shall be allowed for within the dwelling to avoid problems of excess
          condensation. Consider passive ventilation systems with humidity reactive vents, or mechanical
          ventilation systems with heat recovery, if part of a comprehensive improvement scheme.

5.6.2     New windows to incorporate trickle ventilation to comply with the Building Regulations unless
          passive or mechanical whole house ventilation with controlled air inlets is provided.

5.7       Noise

5.7.1     Triple glazed windows or secondary glazing shall be considered for noise reduction in critical

5.7.2     Where sound attenuation is required, acoustically treated natural or mechanical ventilation will be

5.8      Ironmongery

5.8.1     The ironmongery shall be expected to last the life of the window i.e., 30 years.

5.8.2     Hinges shall be of sufficient strength to carry the weight of the window in the various design

5.8.3     Handles for opening, closing, locking etc., shall be easily accessible for occupants to grasp whilst
          standing with their feet on the floor.

5.8.4     Any mechanism that may require manipulation in order to change the position of the window shall
          be easily accessible for occupants to grasp whilst standing with their feet on the floor.

5.8.5     Provision shall be made for elderly and disabled residents where required.

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5.8.6     Windows should have integral locks, and advice should be sought, during the design stage, from
          the London Fire and Civil Defence Authority, Home Office Recommendations and the Crime
          Prevention Design Officer in order to ensure that all requirements are adhered to and that the
          Secured by Design Standard is achieved. Note that Secure by Design requires that windows used
          for ground floor and other accessible locations to be accredited to BS 7950: 1997. Refer to the
          ‘Brief for Security of Individual Dwellings’ for more information, and the SBD website

5.9      Safety

5.9.1     All windows shall have child safety measures built into them and incorporate measures to ensure
          that children are not in danger of falling out of openings. Consideration should be given to the use
          of child locks, restrainers etc. to comply with Building Regulations part K & part N.

5.9.2     Panels below windows and next to doors to comply with Building Regulations part N. Such panels
          could be replaced in appropriate circumstances with insulated panels to improve thermal

5.9.3     Windows should not open in a way that obstructs or causes a safety hazard to any public walkway
          or path.

5.9.4     Large areas of transparent glazing and other critical areas should include manifestation to comply
          with Building Regulations part N.

5.9.5     Advice should be sought from the Police as well as the London Fire Brigade as to how to provide
          secure windows that are safe in the event of fire or other emergency. No locks to be fitted on fire
          escape windows.

5.10      Accessibility

5.10.1 Windows shall be designed for ease of access and operation for all residents, avoiding the need to
       climb in order to operate them, and should be safe to clean in compliance with Building Regulations
       part N.

5.10.2 Handles, opening and locking mechanisms shall be easy to see, grasp and operate. They shall be
       in contrast to the colour/ tone of the window frame.

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5.11      Security

5.11.1 Lambeth’s Crime Prevention Strategy commits to Secured by Design standards. Please refer to the
       ‘Brief for Security of Individual Dwellings’ for more information, and to the SBD website: NB: The key standard for window security is BS 7950: 1997 to which
       the whole window system must be accredited.

5.11.2 Internal beading is preferred. If not possible, external glazing beads should be fixed with security
       glazing tape and pinned. Glazed panels and frames must not be removable from outside the

5.11.3 Security measures should be obvious to act as a deterrent to potential burglars.

5.11.4 Frames must be securely fixed and any external-glazing beads glued or bonded or pinned.


5.11.5 Keys for window locks should be easily obtainable from locksmiths or hardware shops. Robust key
       operated locks are required on all opening windows on the ground floor. Issues regarding the
       provision of keys shall be discussed and agreed with the relevant housing officer.

          Hinged Windows

5.11.6 Secondary locks should secure the frames together. The Police advise that locks which either
       secures the handle or stay-bar should not be fitted.

          Sash Windows

5.11.7 These are to be fitted with key operated sash stops to the upper windows to limit the opening of
       both windows.

5.12      Cleaning

5.12.1 All windows must be easy to clean on both sides from within the dwelling. It should also be possible
       to clean the windows without recourse to a ladder and without leaning out of the building.

5.13      Sealing

5.13.1 It is important that windows are well sealed to the structural opening to minimize heat loss. The seal
       should be formed on the inside of the frame. The seal should be made with water-based acrylic
       mastic applied on a suitable backing. The gap between the frame and the opening should be
       stuffed with mineral wool insulation to prevent cold bridging. The exterior of the joint should be
       protected from water penetration whilst permitting moisture vapour to pass to the outside air.

6         Maintenance
6.1       The chosen method of replacement/renewal should be of a proven quality and have an expected
          life of thirty years. The Contract Administrator (CA) shall provide manufacturer's information and the
          address of a block where a similar solution has been chosen, for both the Client and residents to
          view. This is particularly important in the selection of window types for tower blocks and some
          exposed elevations on medium rise. The Client will expect an example that is similar in terms of the
          performance required.

6.2       Replacement elements should be easily available for maintenance purposes.

6.3       A schedule of works carried out to the various units, details of the suppliers of the window units and
          of any subcontractors and the contact point (name of individual) to whom any query regarding the

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          windows should be forwarded shall be provided on Practical Completion of the works and form part
          of the CDM Health and Safety File.

6.4       A list of components (part Number where applicable), a copy of the relevant company's ordering
          procedure and other supporting documentation shall be provided on Practical Completion. A copy
          of this shall form part of the Health and Safety File and be provided to the AHO / Lead Officer. A
          copy should also be forwarded to the Housing Development Officer.

7         Demonstration of Windows
7.1       A full set of the proposed windows and ironmongery should be made available for demonstration
          purposes for residents, the most suitable place being an occupied property or a void. If these
          options are not available the windows (in working order) should be made available in a location
          agreed by the Client.

7.2       The Contractor shall not place an order for the windows until the Project Team has approved them.
          The contractual programme shall reflect this requirement.

8         Fixing of New Units
8.1       The fixing of units as with all other elements of the window installation shall comply with the
          Performance Specification, the relevant BS Standards and Building Regulations and the
          manufacturer's system of installation in order that the guarantee is valid to protect the Client's

8.2       In occupied premises, windows shall be removed and replaced within the same day.

8.3       Occupiers must be instructed in the operation of the windows on the completion of installations
          within individual dwellings.

8.4       A plastic-backed instruction/help manual shall be given to the occupier at completion of the
          individual installation and spare copies given to the AHO / Lead Officer at hand-over.

9         Internal Decoration Condition
9.1       When undertaking works to the interior of dwellings the best approach of minimising damage to
          decorations shall be adopted.

9.2       The Contractor will carry out a decoration condition audit of the affected area before work
          commences on each dwelling (photographic and written). This audit should be agreed and signed
          by the occupier.

9.3       In cases where the installation will require intensive disturbance the Client will require a
          photographic survey.

9.4       Any works to leaseholders or RTB applicant's premises will require both methods of survey.

9.5       The contractor should always minimise damage to existing decorations. Excessive damage due to
          careless working will be made good by and at the expense of the contractor.

9.6       When designing the proposed scheme the CA will estimate any probable costs regarding
          decoration based on the Council's allowance for decoration per room. Also to be judged will be the
          likely cost of decorating those properties where the occupiers are unable to make good
          themselves. The project team must agree what costs for redecoration can be allowed for from the

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10 Scaffolding
10.1      The CA must ensure that any proposals for scaffolding ensure that the highest standards of security
          to the building are maintained. Please refer also to the ‘Brief for Security of Individual Dwellings’ for
          further guidance.

10.2      As far as is practicable arrange for boarding up to the least number of levels at any given time;
          board up at latest point in the programme (but without undermining the smooth running of the
          contract) thereby affording increased security to the occupiers during works.

10.3      Ladders should be drawn up and locked down or locked away at the close of each days work.

10.4      Standards (the vertical poles) should be painted white, or taped up, or a suitable method employed
          to the Clients satisfaction, to the height of three metres to ensure visibility and contrast with

10.5      All hoarding and scaffolded areas should be adequately lit. Consideration must be given to
          backlighting where appropriate e.g. to sheeted in areas. Backlighting must be referred to in the
          specifications. At briefing stage specific arrangements are to be agreed with the Client.

10.6      Hoardings should incorporate secure vision panels where appropriate.

10.7      The standards should be adequately spaced in entry and exit areas to ensure easy through
          movement for a double buggy or wheelchair.

10.8      Appropriate temporary warning and information signs should be affixed to hoarding and scaffolding
          to inform public and residents. Notices should also be affixed to the building and displayed in lifts
          and other communal areas.

10.9      Safe and appropriate alternative arrangements should be provided wherever part or all of a walkway
          or footpath is obstructed.

11 Inspection Guarantees and Handover
11.1      The CA will inspect the finished work critically. Adequate time will be set-aside for this purpose. The
          client should be fully involved in this process.

11.2      The client requires that the Project Team and other interested parties identified by the client will be
          invited to handover.

11.3      All maintenance schedules are to be available for inspection.

11.4      All guarantees and estimates of life and maintenance programmes are to be recorded and a copy
          passed on to the client.

11.5      The client intends that residents be given an opportunity to comment on the project after
          completion. The CA may be required to participate in this process.

11.6      During the defects period an employee of the Company chosen to do the works will be named and
          will operate as the contact point for all problems to do with the installation and functioning of the
          replaced/renewed windows. All problems should be resolved in less than 72 hours - if this proves
          difficult the Client is to be informed as to the problems and how they are going to be resolved,
          Access to units is to be arranged via the Housing office.

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The Contract Administrator (CA) referred to in this document is the person responsible for design and
supervision of the project. This may be a surveyor, architect or engineer, and be an external or in house

Where the properties are managed by an Estate Management Board or Tenant Management Organisation
all references to the "Area Housing Officer" (AHO) should be substituted for "Estate Management Board
Lead Officer" or "Tenant Management 0rganisation Lead officer" respectively.

Access to units is to be arranged via the Housing office or as may apply any of the above.

 AHO           Area Housing Officer
 ALO           Architectural Liaison Officer
 AO            Area Office
 CPDA          Crime Prevention Design Advisor
 CPO           Crime Prevention Officer
 FED           Front Entrance Door
 LHC           (formerly known as London Housing Consortium)
 SBD           Secured by Design
 CA            Contract Administrator (The person responsible for design and
               supervision of the work)
 EMB           Estate Management Board

 RTB           Right to Buy
 TMO           Tenant Management Organisation

* Contact Jon Lissimore for further information: 020 7926 3572.

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Description: Brief for Window Renewal