EWI to new door - Threshold and head with step

Author details

Original Author:Admin Organisation:Retrofit Pattern Book

Detail summary

Detail for external wall insulation (woodfibre and below-ground), and the installation of a new insulated doorset and insulated reveal; to an existing opening; above an existing ground level with stepped access.

The new door is installed in a softwood timber frame; with the threshold reinforced with steel angles for structural support, with additional structural insulation over extruded polystyrene insulation board, suitable for below ground insulation.

Technical description

Section detail. New door to EWI with stepped access. Threshold and head detail.

Suggested Installation Sequence:

Where existing steps are to be retained, these should be carefully removed to allow installation of external wall insulation and/or perimeter floor insulation. Materials should be set aside for re-use. Reclaimed facing bricks should be sound, free from mortar and deleterious matter.

Reference Specification

For guidance on step access or opening sizes for new and existing doors : Please refer to Approved document M (access to and use of buildings).

Based on specifications of door: Door facings:

  • Laminate: to BS EN 438-1 and -7.
  • Plywood: To BS EN 314, surface appearance to BS EN 636.
  • Hardwood: To BS EN 635-2.
  • Softwood: To BS EN 635-3.

External wood matchboarded doors to BS 459.
Wood framed panel doors:
Timber quality: To BS EN 942.
All adhesives for for wood doors and frames:

  • to BS EN 204 for Polyvinyl acetate (PVAC).
  • To BS EN 12765, class C4 for thermosetting resin.

Fire performance of all doors, Fire resistant doorsets and shutter assemblies:

  • Type testing: To BS 476-22 or BS EN 1634-1.

Smoke control doorsets and shutter assemblies:

  • Type testing: To BS 476-31.1 or BS EN 1634-3.

Intumescent seals:

  • Type testing: To BS 476-23.

Testing authorities to be UKAS accredited.

Single leaf external doorsets to dwellings, security: To BS 8220-1: General to BSI publication PAS 23-1, Specific req. to BSI publication PAS 24.

Safety glazing to door leaves and sidelights to BS 6206 for safety plastics and BS EN 12600 for safety glass. Location: To BS 6262-4.

Perimeter insulation suitable for below ground use and drainage layer. To BS EN 13164

For any new or existing brick/blockwork where not re-used: Aggregate concrete bricks and blocks: To BS EN 771-3. Autoclaved aerated concrete (AAC) blocks: To BS EN 771-4. Calcium silicate bricks: To BS EN 771-2. Clay blocks: To BS EN 771-1.

Cement: To BS EN 197-1 and CE marked.


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.

Parts list

  • Softwood timber frame Boards [GD10]

    • Manufacturer: Contractors choice.
    • Type: Half round edge.
    • Finished size: to suit existing opening.
    • Species: Manufacturers standard.
    • Class: Class 2 to BS 1186-3.
    • Preservative treatment: not required.
    • Finish as delivered: Factory applied priming coat.
    • Fixing: Lost head nails at 30mm centres.
    • Certification: All timber to be FSC certified(or re-used from existing on site).

    Contractors Choice.

  • Insulated External Wood Flush Doorset [GD14]

    Enhanced EcoHomes Doorset.

    • Type: 54mm insulated single leaf door.
    • Target U-value : 1.0 W/m2K
    • Air-tight installation : Install to achieve maximum air-tightness, using appropriate air-tight tape and sealants at all junctions and potential air-leakage points. (expanding PU foam will not be sufficient to achieve adequate air-tightness).
    • Size: As existing.
    • Facings : Manufacturer's standard.
    • Glazing : Factory glazed as required.
    • Finish As Delivered : Factory finished paint system.
    • Ironmongery : Manufacturer's standard, factory fitted.
    • Threshold : Hardwood with mobility threshold seal.
    • Frame : Manufacturer's standard.
    • Handing : As existing.
    • Doorset Fixing : As manufacturer's recommendations.
    • Certification : All timber to be FSC certified.
    • Security : Secured by Design

    Performance Door solutions.. Tel: 01706 370001.
    Email: info@pdsdoorsets.co.uk.
    Product Reference: Enhanced EcoHomes Doorset

  • Sealant To External Door Frames [GD14]

    • Type: silicone
    • Colour: TBC
    • Profile: convex

    Contractors choice

  • Single-sided air seal tape [DP09a]

    Tape for junctions critical to air-tightness. See drawing for locations.

    • Manufacturer: Pro-Clima
    • Size: 60mm
    • Accessories: ORCON F sealant and TESCON PRIMER RP (for use on rough/old surfaces to assist adhesion)

    Pro Clima. Product Reference: TESCON VANA/ TESCON PROFIL (single sided)

  • EWI(Woodfibre), with rendered finish [EW01]

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

    • Insulation back board: UdiTherm SK.
    • Insulation top board: 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 for ground level/below ground level [EW01]

    Extruded Polystyrene (XPS) suitable for below ground conditions and for application of render.

    • Thickness: as EWI.
    • Depth: Minimum 300mm below internal floor level.
    • Thermal conductivity: 0.033W/m2k. GWP: <5.
    • Installation: Cut to fit around compact foam and steel supports to door threshold.
    • Joints: Tight butt joints

    BASF. Product Reference: Styrodur 2800C insulation.

  • Rolled Support Steel Angles [EW06a]

    • Manufacturer: Contractors choice.
    • Type: 65 x 50 x 5 mm rolled steel angle.
    • Finish as delivered:Hot dip galvanised to BS EN ISO 1461.
    • Spacing: at 1/3 points beneath door threshold.
    • Fixing: Mechanically fixed through compacfoam packer to existing masonry. Fixing to suit existing substrate.
    • Top-plate: Top-plate pre-fixed to upper end of angle to take load of threshold through compac foam insulation.

    Contractors choice

  • Structural Insulation beneath door threshold [EW06a]

    Structurally improved Polystyrene insulation beneath door threshold

    • Thickness: as per drawing. Depth as per drawing.
    • Width: as per door threshold.
    • Thermal conductivity: 0.04W/m2k. GWP: <5.
    • Joints: tight butt joints

    Compacfoam structural insulation
    Product Reference: CompacFoam- 200

  • External steps with blockwork to support

    Where difference between threshold and external ground level >200mm external intermediate steps of equal level should be provided. New steps should be constructed in blockwork and masonry, using existing materials on site where possible.
    Steps should be even, with risers of 150mm minimum to 200mm maximum.

    Contractors Choice.


  1. Admin - 2015-04-29 11:06:24 [Displayed version]

    General formatting changes. Pdf file updated as per latest revisions. DWG file updated.

  2. Admin - 2015-04-22 14:18:44

    Pdf file updated as per latest revisions

  3. Admin - 2015-03-27 16:07:00

    Preview image and .pdf file updated.

  4. Admin - 2015-03-23 15:59:36

    General error removal and re-formatting.

  5. Admin - 2015-03-23 15:45:36

    General error removal and re-formatting.

  6. Admin - 2015-03-18 13:06:51

    Version 4- Contact link for "EWI for ground level/within splash zone [EW06a]" updated.

  7. Admin - 2015-03-18 12:22:50

    Version 3-errors removed in technical description.

  8. Admin - 2015-03-18 12:21:40

    Version 2- Title updated. category changes to EWI- door threshold. Technical description added and expanded with BS codes and Approved docs. Parts list added and updated with codes and contact/supply links.

  9. Admin - 2015-02-27 12:36:30

    Version 1

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