23 Oct 2019
Engineering New Zealand has developed a set of template documents to assist engineers in providing clear communication to building consent authorities. These documents are designed to accompany a PS1, calculations and drawings, during the consenting process for residential builds. They've been developed in consultation with councils and engineers.
Templates for design documentation
These forms and templates have been developed for use by engineers for residential design work. You may, on occasion, find that your project falls outside the scope of these documents. You are expected to rely on engineering skills and judgment to understand when that happens and to adapt the documents (or devise your own) so that they are fit for purpose.
The resulting document set, outlined below, is available in our online member area.
The PS1 should define what you’ve designed and are covering in your calculations and drawings. These suggestions will help you avoid common errors:
- Building Code Clause(s) should typically only refer to B1 – don’t put VM1/VM4 in this space. We advise against signing for B2 (more on this later).
- Description of Building Work – be succinct. Descriptions such as Proposed New Building or Proposed Alterations and Extension to Existing Structure work well.
- Extent of engagement – only the items you’re designing, not the whole building.
- Compliance documents – assuming you’re working to the relevant standards, just put the governing Verification Methods here. For example, B1/VM1 and B1/VM4 normally cover the structure and foundations of a building. You don’t need to list the individual standards you’re using as this can be done in the design features report. But be careful if using B1/VM4 as a means of compliance for the foundation design. It has a narrow scope of application and some aspects no longer meet current design practice. We recommend consulting the NZGS/MBIE Earthquake Geotechnical Engineering modules.
Certificate of Work (or RBW Design Memorandum)
We’re aware sometimes the multi-page Certificate of Work document has been altered by other parties without the engineer knowing, then submitted to council. To help stop this, we can offer a memorandum that has been used by some practising engineers. It’s fine to tick both the “designed” and the “supervised” boxes if more than one person has worked on a project.
Restricted building work currently only applies to aspects of residential construction including foundation and structural design.
Design features report
Many complaints from reviewing engineers and councils are because design assumptions aren’t clearly laid out. We’ve provided a template DFR primarily designed for residential work. It provides an example of how to clearly show your assumptions and imposed and dead loads at the beginning of your documentation.
B2 letter and schedule
We advise against specifically covering B2 on your producer statements because you achieve a compliance pathway when your calculations comply with the relevant standards. The letter on our website can be presented to the BCA, along with a maintenance schedule if required.
Site inspection schedule
Several engineers put “inspections as agreed with owner” on the documentation. However, BCAs, builders and owners need to know exactly what engineers are going to be inspecting, and at what stage of construction. With our site inspection schedule template, delete items that aren’t applicable to your job and add others as required. Number them in the order that you’ll be going to see them and include what you will inspect.
Finally, another useful resource is MBIE’s Guidance on the use of Certificates of Work, Producer Statements, and Design Feature Reports by Chartered Professional Engineers under the new Restricted Building Work regime developed to assist the Canterbury rebuild.