scope:

Construction requirements

NZS 3604 sets out construction requirements for timber-framed buildings within the limits specified in 1.1.2.

See figure 1.1 and figure 1.2 for information on determining if a building is covered by NZS 3604.

Buildings covered by this Standard

NZS 3604 shall apply only to buildings within the following limits:

(a) Buildings founded on good ground;

(b) Importance Level 1 and Importance Level 2 buildings (see table 1.1);

(c) The total height from the lowest ground level to the highest point of the roof up to 10 m;

(d) The open ground snow loading up to 1 kPa for buildings designed in accordance with the main body of this Standard. For snow loads up to 2 kPa see section 15;

(e) Buildings with floor loads not exceeding 3 kPa uniformly distributed load, or 2.7 kN concentrated load on the floor, or 0.25 kPa uniformly distributed load on the roof. The floor live loadings shall be as given in table 1.2, provided that the floor loading does not exceed 1.5 kPa for the uppermost floor of three-storey buildings (see figure 1.2);

(f) Single-storey buildings may include a part storey basement or a part storey in the roof space. Single-storey buildings shall be supported on any one or a combination of the following foundation structures:

(i) Piles

(ii) Foundation walls

(iii) Concrete slab-on-ground;

(g) Two-storey buildings shall comprise a timber upper floor and upper storey timber walls. The lower storey walls may be timber, or full height concrete masonry to NZS 4229. The lower floor may be slab-on-ground or suspended timber as follows:

(i) For buildings with slab-on-ground the lower storey walls shall be in timber framing, or full height concrete masonry to NZS 4229

(ii) Buildings with the lower floor of suspended timber and lower-storey timber walls shall be supported on either or a combination of foundation walls and piles

(iii) Buildings with the lower floor of suspended timber and lower storey full height concrete masonry walls shall be supported on foundations to NZS 4229;

(h) Three-storey buildings shall consist of all the following:

(i) No more than two storeys supported on timber framing

(ii) One storey shall be a part storey in a roof space

(iii) The middle storey and part storey shall be directly supported on a lower storey of concrete masonry walls and foundation walls to the provisions of NZS 4229

(iv) The ground floor shall be either concrete slab-on-ground or a suspended timber or concrete floor to the provisions of NZS 4229;

(i) The slope of any roof plane shall not be steeper than 60° to the horizontal;

(j) For the purpose of forming a mansard roof only, a wall of an uppermost storey may slope by up to 20°;

(k) The building wind zone determined from 5.2.1 and table 5.1 shall be Low, Medium, High, Very high or Extra high (i.e. L, M, H, VH or EH). Specific engineering design (SED) in table 5.4 indicates the application is outside the scope of the Standard;

(l) The plan floor area shall:

(i) Be unlimited for one or two-storey buildings where all storeys are of timber frame

(ii) Not exceed 300 m² for two-storey buildings of other forms of construction

(iii) Not exceed 250 m² for three-storey buildings of other forms of construction;

(m) Buildings with wings or blocks shall be designed as if the wing or block was a separate building;

(n) Concrete slab-on-ground floors in accordance with 7.5 may be used for vehicle garages for vehicles up to 2500 kg tare;

(o) Masonry veneer cladding shall have:

(i) A mass not exceeding 220 kg/m²

(ii) A height above finished ground level not exceeding 7 m

(iii) A maximum height of 4.0 m measured from the top of the concrete masonry wall, foundation wall or slab edge foundation. In the case of a veneer-faced concrete block wall or foundation wall, the cladding shall be measured from the top of that wall

(iv) A maximum veneer height of 5.5 m on a gable end wall.

Buildings not covered by this Standard

The following buildings are excluded from NZS 3604:

(a) Buildings without external walls, such as free standing carports and pergolas;

(b) Buildings outside the limitations of 1.1.2 and buildings in table 1.1(b). Such buildings shall be the subject of SED, or an alternative solution.

Structural elements not covered by this Standard

Structural elements outside the generic prescriptions and design tables of this Standard including their durability shall be the subject of SED taking into account the element as well as the impact of resulting load paths on the structure.