Legal requirements for enclosing an existing porch or deck

ARTICLE Dennis Monastra

The enclosure of an existing house porch or deck, like all new building work, must meet the relevant performance requirements of the Building Code.

Also, all new building work (unless it is exempted minor work) must receive a building consent before it is carried out. A consent for your design can be obtained from your local council.

The enclosure of an existing porch does not need a building consent if the enclosed porch has a floor area no larger than 5m2. However, even if it doesn’t need a consent, remember that the building work will still need to meet the relevant Building Code performance requirements.

If you do need a building consent, your building work is considered an alteration to an existing building. This means you may need to upgrade the existing house for means of escape from fire, which includes installing smoke detectors. In all other respects, your must be rendered no worse than before you carried out the alteration.

So what are the relevant performance requirements of the Building Code when you enclose an existing porch or deck?

When you enclose an existing porch, the main requirements you need to meet are for structure, weather tightness, energy efficiency, internal moisture and durability.

However, other Building Code requirements, such as those for access routes, electricity and safety from falling, may also be relevant depending on the work being done.

If your design plans include electrical work, you should consult your electrician.

Some of the aspects of the work may be restricted building work. If the building work carried out is to the primary structure or weather tightness aspects of the building, and a building consent is required, then it must be designed and carried out by a licensed building practitioner. 

You should get appropriate design advice before starting your project, for example from an architectural designer or a Licensed Building Practitioner (LBP) who holds a design license, and that you get a practitioner with appropriate building expertise in carrying on the work (note this person may need to be licensed if restricted building work is involved.

The building code can be viewed at the ABCB website.

This article featured on page 43 of Issue 003 of Renovate Magazine. Renovate Magazine is an easy to use resource providing fresh inspiration and motivation at every turn of the page.

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