Windows and doors in existing buildings

This is a new exemption, introduced in October 2008.

Exemption (ae) of Schedule 1

A building consent is not required for the following building work:

(ae) the installation, replacement, or removal in any existing building of a window (including a roof window) or an exterior doorway if—

(i) compliance with the provisions of the building code relating to structural stability is not reduced; and

(ii) in the case of replacement, the window or doorway being replaced satisfied the provisions of the building code for durability.

Guidance

This exemption allows the installation, replacement, or removal of windows (including a skylight) or an external doorway as long as the building work does not reduce compliance with the provisions of the Building Code that relate to structural stability.

In many cases, external walls are often load-bearing, meaning they support the structure above them, such as a roof or a second storey. External walls also often contain bracing elements (such as bracing rated gibraltar board) that when combined help the building stand up to strong winds and earthquakes. A building’s roof structure is commonly formed using either trusses or rafters and is exposed to significant pressures such as wind (causing uplift) and snow (adding additional weight) in certain areas. In large rooms within buildings, the ceiling linings can also contain structural bracing elements (similar to bracing in a wall and known as a diaphragm ceiling).

Reducing compliance with the structural stability provisions of the Building Code will often occur if any structural members or components are affected (eg, cutting through load-bearing walls, bracing elements or roof trusses to form an opening for a window, door or skylight). In these instances, this exemption cannot be used and a building consent must be obtained.

Additionally, if a window, door, or skylight is to be replaced, then it is important to consider whether it originally met the durability requirements of the Building Code. Doors and windows in an external wall are required, in most cases, to last at least 15 years. Most windows and doors should achieve this requirement with regular maintenance. However, if you are replacing a window, door, or skylight that has been installed within 15 years and it has failed (eg, rotted out), this work will require a building consent. If the door or window is older than 15 years and has rotted out and you are replacing it, then this work does not require a building consent. This recognises that replacing a window or door that has failed its durability requirements with a similar window or door could result in the replacement also failing.

Remember, all building work must comply with the Building Code.

Examples where this exemption could apply

Examples where building consent is required

Installing a skylight into an existing roof, between trusses, so that the structural stability of the roof framing is not reduced (ie, the building’s trusses are not altered in any way). Replacing a window with a door in an external load-bearing wall, as long as the width of the opening does not change and therefore the existing lintel is not altered. The wall framing below a window, in most cases, is not structural and can be removed under this exemption. Removing a window and covering the opening with external cladding and internal linings, to form a wall with no opening. (Note that certain minimum Building Code requirements are still required to be met for ventilation, natural light and visual awareness for the internal space.)

A window that was installed in a building only six years ago is to be replaced due to a rotten timber window frame. Replacing this window requires a building consent because it has failed its 15-year durability requirement. An opening is formed in an external load-bearing wall to install a new window. A lintel is required to support the roof load above. The building work to install the window and the structural lintel will require a building consent. An opening is formed in a roof and the ceiling below to install a skylight. Although the installation does not affect the structural roof members, the room below is large and the ceiling is a bracing element (diaphragm ceiling). This will reduce the building’s compliance with the Building Code that relates to structural stability, so a building consent is required.