Adding a roof to a pergola: what changes?

An open pergola and a roofed structure are different

MBIE’s pergola exemption covers a simple framed structure without a roof, whether attached to a building or freestanding. Adding polycarbonate does not preserve that unroofed status because you can see through it. The roofed proposal must be assessed under the rules that apply to that structure.

Describe the finished installation when you enquire. Include the roofing product, the size of the covered area, the height and whether it attaches to the house. For opening louvres or another proprietary system, provide the actual product information rather than assuming that an open setting decides its classification.

Some roofed structures have their own exemptions

Certain porches and verandas on or attached to an existing building can qualify for a separate exemption up to 20 m², subject to the stated conditions. For more than 20 m² and up to 30 m², separate pathways require ground-level work that does not overhang an area accessible to the public. The design and construction must have the specified LBP involvement, or follow a Chartered Professional Engineer’s design or design review. Check every condition of the chosen pathway.

A freestanding roofed structure needs its own assessment. Do not apply an attached-veranda rule to it automatically. Send drawings and product instructions to the people checking the proposal, and ask them to confirm which pathway they are using. Auckland planning requirements also need to be checked.

Plan the rainwater route before installation

MBIE’s porch and veranda guidance requires roof water to be disposed of in accordance with the Building Code. New drains must be laid by an authorised drainlayer. Depending on the work, council approval and drainage advice may be needed.

For your project brief, record where the roof currently sheds water, where gutters and downpipes could go, and what happens near the house in heavy rain. Ask for the drainage scope to be written into the proposal. A pipe ending at the ground and a connection to an appropriate drainage system are different scopes of work.

Check the house connection and the existing supports

Ask what carries the roof loads and how the junction with the house will remain weathertight. A neat external finish does not show the structure behind it. Existing posts, fixings and foundations should be assessed for the proposed installation instead of assumed suitable because they held an open frame.

Useful information includes the original plans, installation instructions, any consent records and clear photographs of accessible fixings. If those details are concealed, agree what access or investigation is needed. Keep that investigation separate from a promise that the finished design is already resolved.

TrickyBuilds can discuss the building scope and the specialist information needed next. The written quote should identify the roof, structural work, drainage and any excluded professional services so you can see what you are approving.