2019 – December

The following updates to the NZ Metal Roof and Wall Cladding Code Practice (COP), are effective 1 December 2019.

Major Revisions

  1. For this update, the COP section Roof Drainage and all its sub-clauses have been substantially revised. The updates focussed heavily on creating new online tools for calculating Roof Drainage, Gutter Capacity, Downpipe Capacity and Valley Capacity, which are located in Capacity Calculations.

Summary of other changes in this update

  • All the content in Roof Drainage has been updated to provide clarity and brevity, and detail drawings are updated.
  • The previous methods of capacity calculations, using two distinct methods based on standard sizes, have been removed and replaced by online calculator in Capacity Calculations.
  • New clauses have been added for Point Load Testing and Point Load Testing Standards under Structural Testing.
  • The Glossary has been updated with definitions for Swiss Gable, Finial, and Profiled Washer; and some minor edits to refine definitions and grammar fixes.

Revision Detail - 2019 - December

CategoryClause Number (at time of update)Clause (As of current publication)Details
2 - Editing and rearrangement1Introduction Update Revisions Message
2 - Editing and rearrangement2.1Definitions Revised definition of "Load Spreading Washer", added a new item "Profiled Washer", added definition for "Finial",  minor grammatical fixes.
2 - Editing and rearrangement5Roof Drainage The entire Roof Drainage-clause had been revised.
1 - Minor Errata5.1NZBC: Clause E1 — Surface Water Formatting
4 - Clause Inserted Types of Gutter New clause.
4 - Clause Inserted External Gutters (Spouting) New clause.
2 - Editing and rearrangement5.5.5Concealed Fascia Gutters This clause had been completely revised and renamed.
2 - Editing and rearrangement5.5.4Internal Gutters Clause completely revised.
4 - Clause Inserted Internal Gutter Design Features New clause.
2 - Editing and rearrangement5.6Valleys   Valleys had been completely revised and divided into smaller, more specific, sections.
4 - Clause Inserted Valley Fixing New clause.
4 - Clause Inserted Valley Design New clause.
4 - Clause Inserted Internal Corners New clause.
2 - Editing and rearrangement5.6.2Bifurcated Valleys The clause had been revised. Valleys are now discussed in smaller, more specific, clauses.
4 - Clause Inserted Changing Angles in Valleys New clause.
4 - Clause Inserted Asymmetrical Valleys New clause.
4 - Clause Inserted Roof Gutters New clause.
3 - Substantial change to recommendation5.5.7Secret Gutters Clause revised, for brevity and clarity.
4 - Clause Inserted Rainwater Heads, Sumps, and Overflows New clause.
2 - Editing and rearrangement5.8.1Rainwater Heads Clause revised, now providing more information.
2 - Editing and rearrangement5.8Sumps This clause has been revised.
2 - Editing and rearrangement5.8.2Overflows Clause renamed, Outlets are now discussed under Outlets and Downpipes.
4 - Clause Inserted Outlets and Downpipes New clause.
4 - Clause Inserted Placement of Downpipes New clause.
4 - Clause Inserted Capacity Table for Common Size Downpipes New clause.
2 - Editing and rearrangement5.5.1Gutter Installation and Maintenance Clause has been revised and edited.
4 - Clause Inserted Maximum Gutter Length New clause.
2 - Editing and rearrangement5.5.2Gutter Support Systems Clause revised.
4 - Clause Inserted Gutter Maintenance New clause.
2 - Editing and rearrangement5.2Roof Drainage Design Clause had been completely revised.
2 - Editing and rearrangement5.3.1Catchment Area Caluse has been completely revised. All calculations are now under a new clause Capacity Calculations.
2 - Editing and rearrangement5.5.8Gutter Fall Clause revised and renamed.
3 - Substantial change to recommendation5.3Rainfall Intensity Clause had been completely revised, with updated Rainfall Intensity Maps at the end of the main Clause, Roof Drainage. 
4 - Clause Inserted Allowance for Short-Term Intensities New clause.
4 - Clause Inserted Duration New clause
2 - Editing and rearrangement5.3.2Capacity Calculations The old clause, Capacity Calculations, replaced by a new clause of the same name but including new online tools.
4 - Clause Inserted North Island 50-year ARI, 10-minute Rainfall Intensity Map New clause.
4 - Clause Inserted South Island 50-year ARI, 10-minute Rainfall Intensity Map New clause.
4 - Clause Inserted8.3Flashing Cover Adjusted spacing in Table 8.3A
2 - Editing and rearrangement8.4.4.3Step Apron Removed reference to "Fortress Fasteners" in drawing A:  Step Apron Details.
4 - Clause Inserted8.4.4.4Eaves Flashing Drawing renamed to Gutter Flashing.
2 - Editing and rearrangement12.2Purlin Creasing Inserted photograph.
4 - Clause Inserted17.1.2Point Load Testing Standard New Clause.
4 - Clause Inserted17.3.2Point Load Testing New clause.
1 - Minor Errata18.8Sheet Metal Work For Roofing Contractors. Clause revised for gender neutrality. No significant changes.
4 - Clause Inserted 2019 – December Summary of Changes – December 2019
0 - Clause Removed5.3.2.1Method 1: Gutter and Downpipe Capacity Determined by GraphThese methods have been replaced by online capacity calculating tools.
0 - Clause Removed5.3.2.3Method 2: Gutter and Downpipe Capacity Determined by CalculationsThese methods have been replaced by online capacity calculating tools.
0 - Clause Removed5.3.3Roof Cladding CapacityThese methods have been replaced by online capacity calculating tools.
0 - Clause Removed5.4SnowClause removed, Snow and hail are comprehensively discussed in Snow Loads.
0 - Clause Removed5.4.1HailClause removed. Leaf guards and maintenance are discussed under Gutter Maintenance.
0 - Clause Removed5.5GuttersThe clause had been removed. Gutters are now discussed in more detail in a separate clause for each type, under the main clause Types of Gutter.
0 - Clause Removed5.5.3Eaves GuttersClause deleted. Now discussed under External Gutters.
0 - Clause Removed5.6.1Valley CatchmentThis clause had been replaced with the newly developed online tool in Valley Capacity Calculations.
0 - Clause Removed5.7DownpipesInformation previously contained in this clause is now discussed in Outlets and Downpipes.
Out-of-band updates 16/12/2019
2 - Editing and rearrangement5.4.2ADownpipe Capacity TableRemoved obsolete column for Roof Area Drained as the online calculator replaces this.
2 - Editing and rearrangement5.7Capacity CalculationsAdded link to Common Sized Downpipes.
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Summary of Changes – December 2019