EWI around meter box

Author details

Original Author:Admin Organisation:Retrofit Pattern Book

Detail summary

Detail for external wall insulation to new/existing meter box. This detail presumes the application of internal wall insulation, on the interior side of the wall opposite the meter box at a future date to prevent cold bridging, but does not require the installation of both external and internal insulation at the same time.

Because of the the need to keep a required distance around gas meters and pipes as part of EWI works, it is recommended that Internal wall insulation be installed at a future date to the internal wall behind the existing meter. A 300mm overlap to the EWI on the external wall combined with insulation works to the existing ground floor is expected to mitigate cold bridging caused by carrying the EWI around the meter box.

Technical description

Section detail. EWI installed around existing meter box at perimeter. Internal floor to be insulated as part of works and potential for internal wall insulation to prevent cold bridging. No ground works or excavation within given distance of gas pipe as shown on drawing.

Suggested Installation Sequence


  1. Attach door frame to meter box and fix in place and tape.
  2. Fix EWI as per detail.
  3. Render.
  4. Installation of internal floor insulation as required.

Reference Specification:

Refer to Approved Document P: Electrical safety- Dwellings for works involving Meter boxes and electrical inlet.


Care should be taken to ensure air-tightness. Seal all service penetrations through EWI and existing wall. Lap and tape all membranes around edges of EWI system.

All insulation to be continuous to avoid thermal bridging.

Preparation of external wall: Remove any existing loose material and prepare in accordance with manufacturer's requirements.

Any alterations to drainage and other fixtures, or work to prepare the substrate, to be agreed with contract administrator prior to work being undertaken. Prior to start on site inspect the form and condition of the structural substrate; institute repairs and/ or additional works necessary to make the substrate suitable to receive EWI system.

Existing gas meters and inlets are to be left in-situ. Insulation to be fitted round them as closely as possible, whilst ensuring they are still properly ventilated. Care should be taken when excavating close to gas mains.

Parts list

  • EWI (Woodfibre) System,Rendered Finish [EW01]

    Composite woodfibre board for use on solid and hard to treat cavity walls.

    • Insulation back board: 100mm UdiTherm SK.
    • Insulation top board: 100mm Diffutherm NF (T&G, renderable).
    • Thermal conductivity: 0.045W/m2K. GWP 0.
    • Base Coat: levelling on substrate: 90% contact required around edge of boards between board and substrate to prevent thermal bypass. If substrate is very uneven, use base-coat material around edge of board to achieve contact.
    • Fixing: Fixed mechanically to substrate in accordance with manufacturers recommendations.
    • Render/carrier: to manufacturers standard.
    • Render: Udi Perl
    • Decorative finish: tbc
    • System guarantee: 25 years - ECO compliant insurances and guarantees.
    • System Certification : ETAG

    Unger-Diffutherm. Product Reference: UdiFRONT.
    Supplied by: Back To Earth.
    Tel: 01392 861763
    Web: http://www.backtoearth.co.uk/

  • EWI (Woodfibre) accessories [EW01]

    Base plinth to exposed insulation edge.

    As EWI manufacturer.

  • Woodfibre Insulation Between Floor Joists [FL01]

    Woodfibre Insulation.

    • Thickness 200mm.
    • Friction fit between joists to ensure air-tightness- cut batts approx 20mm wider than opening between joists.
    • Supported: Polyester webbing drawn underneath insulation at approx 600mm centres, fixed to joists.

    Unger-Diffutherm. Product Reference:Reference: UdiFLEX
    Supplied by: Back To Earth.
    Tel: 01392 861763
    Web: http://www.backtoearth.co.uk/


  1. Admin - 2015-04-29 13:57:55 [Displayed version]

    Parts list contact details for FL01 and EW01 amended to include Back to Earth contact details. DWG file uploaded.

  2. Admin - 2015-03-27 16:45:17

    Preview image and .pdf file updated.

  3. Admin - 2015-03-24 17:49:31

    General formatting. Approved doc links added in technical description. Parts list updated with suppliers links.

  4. Admin - 2015-03-13 14:28:41

    Technical description updated with information for meter boxes.

  5. Admin - 2015-03-13 14:09:49

    Title updated. Technical description expanded. Parts list added.

  6. Admin - 2015-02-27 17:35:23

    Version 1

Leave a comment


  1. For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.

    User name

Leave a comment


A total of 14 users have left feedback about this detail.

Share your thoughts about this detail with other users:

Feedback summary

  • 80% of users found this detail easy to implement.
  • 50% of users found it easy to source skills for this detail.
  • 60% of users found this detail hard to understand.
  • 100% of users found the overall cost for this detail to be low.
  • 90% of users found materials for this detail easy to source.