v26.09 September 2026
In one of our busiest revisions yet, v26.09 of the Code of Practice features a long list of new and revised detail drawings.
Important Revisions and New Content
Flashing Expansion Details and recommendations have been extensively revised, and new detail drawings have been added showing ridge and transverse flashing expansion joints.
We have added Window Flashing Details for vertical and horizontal corrugated wall cladding. These have been tested to comply with E2/VM1.
The spacing and gap requirements for residential spouting with overflow to be categorised as drained along the length specified.
We changed the recommended minimum freeboard for Bifurcated Valleys to 20 mm and added a recommendation for a valley baffle to be fitted to lower valleys.
To aid in placement of first purlins, we added the positions for first purlins on hips to Ridge and Head Flashing Cover Table. The revision also included layout edits to the other tables in Flashing Cover, with no changes to recommendations.
New drawings were added to Minimum Freeboard Values to clearly show the freeboard required for different gutter types.
To reduce ambiguity and improve clarity, we made minor changes to illustrations in the Gutter Capacity Calculator.
Cricket Over-Flashing More Than 1 m Wide, previously called "Cricket over-Flashing More than 1m Wide", now shows two options for large over-flashings.
In line with manufacturers' literature, we amended the CoP recommendation for Minimum Roof Cladding Pitch to 3° for trapezoidal profiles with a rib height of 30 mm or more.
A new drawing in Parapet And Apron Capping Terminations now shows the preferred termination of an Apron Flashing.
A new clause, External Gutter Designs, contains drawings showing the basic shapes of external gutters.
Editing and Rearrangement without changes to recommendations
The clause Vented Soft Edge has been revised to remove ambiguity.
We added a definition to the Glossary for Solid Fixing and revised the definition of Freeboard to improve clarity.
A new link to the to home page of ECIA will aid in finding the best guidance for Maintenance and Washing of roofs.
Parapet Cappings now clearly show packers required to support various parapet cappings and Ventilation Pathway: Top Plate with Fleece now shows the correct airflow at the top plate for fleece-lined roof cladding.
The rest of the 26.09 revision consisted of minor errata and changes to layout to aid usability, with no changes to recommendations.
(item needs a title)
| Category | Clause Number (prior to update) | Clause (As of current publication) | Details |
|---|---|---|---|
| 3 - Substantial change to recommendation | 8.10 | Flashing Expansion and Contraction | Substantial revision with new recommendations and new details for expansion joints in flashings. |
| 3 - Substantial change to recommendation | 8.10.1 | Flashing Buckling Due to Timber Shrinkage | This clause was part of a complete revision of Flashing Expansion Details. |
| 4 - Clause Inserted | Flashing Buckling Due to Thermal Movement | A new clause created during the revision of Flashing Expansion Details. | |
| 4 - Clause Inserted | Recommended Expansion Joint Spacing for Flashings | New clause created during the revision of Flashing Expansion Details. | |
| 4 - Clause Inserted | Expansion Details for Flashings | A new clause for expansion joint details for flashings. | |
| 4 - Clause Inserted | Window Flashing Details | A new clause showing window flashing details which were tested to comply with E2/VM. | |
| 3 - Substantial change to recommendation | 5.4.2 | Gutter Capacity Design | Now defining the minimum size for residential spouting overflow. |
| 2 - Editing and rearrangement | 1, 1 | Introduction | New revision message for v26.09, published on 1 September 2026. |
| 2 - Editing and rearrangement | 2.1, 2.1 | Definitions | Updated definition for Lap Tape. |
| 4 - Clause Inserted | External Gutter Designs | New illustrations showing different external gutter shapes. | |
| 1 - Minor Errata | 5.4.7 | Gutter Capacity Calculator | Change illustration label from 'Depth' to 'Upstand' for consistency with input box and clarified instructions for calculator use. |
| 2 - Editing and rearrangement | 5.5.3 | Bifurcated Valleys | |
| 2 - Editing and rearrangement | 7.1.1 | Minimum Roof Cladding Pitch | Changed the minimum pitch for symmetrical trapezoidal > 30mm to 3° to bring it in line with manufacturers' recommendations. |
| 2 - Editing and rearrangement | 8.4 | Flashing Cover | Layout changes to the cover tables to improve usability. |
| 2 - Editing and rearrangement | 8.5.2 | Barge And Verge | Adjusted the layout of drawings into two columns to improve navigation. No changes to recommendations. |
| 2 - Editing and rearrangement | 8.5.3 | Parapet Cappings | Updated detail drawings for parapet caps. |
| 2 - Editing and rearrangement | 8.5.4.1 | Apron and Parapet Capping Terminations | Title edit, layout change, and a new drawing showing details for Apron Terminations. |
| 4 - Clause Inserted | 8.11 | Wall Cladding | New drawing showing a Proprietary Wall Vent Cover. |
| 1 - Minor Errata | 9.4.2.6 | Penetration Flashings on Trapezoidal Profiles | Image resizing. |
| 3 - Substantial change to recommendation | 9.4.2.7 | Over-Flashing More Than 1m Wide | New drawings showing alternative details. |
| 1 - Minor Errata | 9.4.3 | Dormer Details | Reformatting of Gable Dormer Valley: Corrugate. No other edits or changes to recommendations. |
| 2 - Editing and rearrangement | 10.10.1.4 | Vented Soft Edge | Editing to remove ambiguity |
| 2 - Editing and rearrangement | 10.10.2 | Battens | Editing of Ventilation Pathway: Top Plate with Fleece. |
| 2 - Editing and rearrangement | 14.18.5 | Colour Matching Paint | Revised for clarity. |
| 2 - Editing and rearrangement | 16 | Maintenance | Added a link the home page of the Exterior Cleaning Industry Association. |
| 2 - Editing and rearrangement | 16.7 | Washing | Added link to ECIA homepage. |
| 4 - Clause Inserted | v26.09 September 2026 | Latest revision. |
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