Part 3.3.5 Masonry veneer

NCC 2019 Volume Two

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Building Classification

Classification

Part 3.3.5 Masonry veneer

Appropriate Performance Requirements

Appropriate Performance Requirements

Where an alternative masonry veneer wall system is proposed as a Performance Solution to that described in Part 3.3.5, that proposal must comply with—

Performance RequirementP2.1.1; and
Performance RequirementP2.2.2; and
Performance RequirementP2.2.3; and
the relevant Performance Requirements determined in accordance with A2.2(3) and A2.4(3) as applicable.

3.3.5.0

Performance RequirementsP2.1.1, P2.2.2 and P2.2.3 are satisfied for masonry veneer if it is designed and constructed in accordance with one of the following:

(a)

AS 3700.

(b)

AS 4773.1 and AS 4773.2.

Acceptable Construction Practice

3.3.5.1 Application

Compliance with this acceptable construction practice satisfies Performance Requirements P2.1.1, P2.2.2 and P2.2.3 for masonry veneer provided—

(a)

the building is located in an area with a design wind speed of not more than N3; and

(b)

masonry veneer walls are constructed on footings that comply with Part 3.2; and

(c)

the building site soil classification is A, S or M; and

(d)

the framing that the masonry wall is tied to complies with Parts 3.4 and 3.0 as appropriate; and

(e)

the building is not constructed in an alpine area; and

(f)

the building is one for which Appendix A of AS 1170.4 contains no specific earthquake design requirements.

3.3.5.2 Height of wall limitation

Masonry veneer walls must not be greater than 8.5 m in height when measured above the adjacent finished ground level.

3.3.5.3 Masonry units

(a)

Masonry units must have a minimum characteristic unconfined compressive strength of—

(i)

3 MPa for solid or cored units; or

(ii)

10 MPa for hollow units.

(b)

Masonry veneer walls must have a minimum veneer thickness of 90 mm.

(c)

Subject to (d), masonry units must be—

(i)

either clay or calcium silicate brick or concrete brick or block; and

(ii)

classified and used in the exposure conditions appropriate to their classification as described in Table 3.3.5.1.

Table 3.3.5.1 Exposure conditions

Exposure classification	Masonry application
Protected (P)	Suitable for use in locations such as— internal walls; and external walls that are coated or rendered; and walls above damp-proof courses provided the wall is protected at the top by a roof, eaves, coping, topping or the like.
General purpose (GP)	Suitable for use in all locations except those where 'Exposure class' is required.
Exposure class (Exp)	Suitable for use in all locations including severe local conditions such as— below the damp-proof course in areas where walls are expected to be attacked by salts in the ground water or brickwork itself (salt attack or salt damp); and on sea fronts where walls are exposed to attack from salt spray; and in heavily polluted areas subject to deposition of atmospheric pollution; and under regular cyclic freeze and thaw conditions.

Explanatory information:

The exposure classification or durability of a masonry unit is a measure of its resistance to attack by soluble salts, either in the ground or in the atmosphere. All masonry products manufactured are classified by their durability. The majority of uses will require either an Exposure class (Exp) product or a General Purpose (GP) product.

(d)

Mixing of panels consisting of clay masonry units with panels consisting of concrete or calcium silicate masonry units is not permitted unless—

(i)

at vertical junctions, a control joint is installed; and

(ii)

at horizontal junctions between panels of different materials, a slip joint using a membrane similar to that used for damp-proof courses is installed.

3.3.5.4 Mortar mixes

Mortar used for masonry construction must comply with AS 3700 or AS 4773 except that the mortar may be mixed by volume in the proportions stated in Table 3.3.5.2.

Table 3.3.5.2 Acceptable mortar mixes

Mortar mix by volume ^{Note 1}

Cement:lime:sand

Brick exposure classification

General use

Suitable for concrete masonry ^{Note 2}

Protected

1:2:9

1:0:5

General purpose

1:1:6

1:0:5

Exposure class

1:0.5:4.5

1:0:4.2

Notes to Table 3.3.5.2 :

Additives may be used provided they comply with the appropriate specified rate.
Mortar mixes for masonry require the use of methyl cellulose water thickener.

3.3.5.5 Mortar joints

(a)

Unless otherwise specified, masonry bed and perpend joints must have a nominal thickness of 10 mm.

(b)

Where raked joints are used they must not be—

(i)

raked deeper than 10 mm; or

(ii)

used in saline environments or areas subject to heavy industrial airborne pollution.

3.3.5.6 Cavities

The clear width of a cavity between the masonry veneer and the exterior face of the supporting frame must be not less than 25 mm wide and where the masonry veneer is constructed on a slab-on-ground, the cavity must be drained to the outside in accordance with 3.3.5.9.

Explanatory information:

The 25 mm clear width of the cavity needs to be maintained regardless of any wall membranes, sheet bracing or services installed to the supporting frame.

3.3.5.7 Damp-proof courses and flashings — material

Damp-proof courses and flashings must consist of—

(a)

a material that complies with AS/NZS 2904; or

(b)

embossed black polyethylene film of high impact resistance and low slip, with a nominal thickness of 0.5 mm prior to embossing, and comply with clause 7.6 of AS/NZS 2904; or

(c)

polyethylene coated metal, that has an aluminium core of not less than 0.1 mm thick, is coated both sides with bitumen adhesive enclosed in polyethylene film of not less than 0.1 mm thick on each face, and has a nominal total thickness of not less than 0.5 mm prior to embossing; or

(d)

bitumen impregnated materials of not less than 2.5 mm thick, that comply with clause 7.5 of AS/NZS 2904; or

(e)

termite sheet materials complying with Part 3.1.4 (with no penetrations) serving the purpose of a damp-proof course and/or flashing that is continuous through the wall or pier.

3.3.5.8 Damp-proof courses and flashings — installation

(a)

Damp-proof courses and flashings must be—

(i)

located so as to form a continuous damp-proofing barrier—

(A)

around the bottom perimeter of walls where constructed on a concrete slab; and

(B)

in walls and piers below suspended floors; and

(C)

where a masonry wall passes through a roof; and

(D)

where a roof abuts an external masonry wall; and

(E)

to the bottom and tops of windows and doors and the like in accordance with (c), except a damp-proof course or a flashing need not be provided to the top of a window or door where the opening is protected by an eave of a width more than 3 times the height of the masonry veneer above the opening; and

(ii)

continuous through the wall or pier and be visible from the outside face of the wall.

(b)

The location of a damp-proof course or flashing serving as a damp-proof course, must be not less than—

(i)

150 mm above the adjacent ground level; or

(ii)

75 mm above the finished surface level of adjacent paved, concreted or landscaped areas that slope away from the wall; or

(iii)

50 mm above finished paved, concreted or landscaped areas complying with 3.1.3.3(b)(ii) and protected from the direct effects of the weather by a carport, verandah or the like; or

(iv)

in low rainfall intensity areas—

(A)

15 mm above finished paved, concreted or landscaped areas; or

(B)

0 mm above finished paved, concreted or landscaped areas if the damp-proof course is protected from the direct effects of the weather by a carport, verandah or the like.

(c)

Sill and head flashings serving openings must be—

(i)

installed so that the flashing extends not less than 150 mm beyond the reveals on each side of the opening; and

(ii)

located not more than—

(A)

one course below the sill brick course; and

(B)

300 mm above the opening; and

(iii)

turned up in the cavity not less than 150 mm above the opening; and

(iv)

embedded not less than 30 mm into the masonry veneer; and

(v)

attached to the window or wall framing.

3.3.5.9 Weepholes

(a)

Except where excluded by (b), open perpendicular joints (weepholes) must be created in the course immediately above any flashing (including above any damp-proof course acting as a flashing) and be—

(i)

a minimum of 50 mm in height, by the width of the vertical mortar joint; and

(ii)

at not more than 1.2 m centres; and

(b)

Weepholes are not required in the following locations:

(i)

Where head openings are less than 1.2 m wide.

(ii)

Beneath window and door sills.

3.3.5.10 Wall ties

Veneer wall ties must—

(a)

comply with AS/NZS 2699.1 and be—

(i)

light duty veneer ties in areas where the design wind speed is not more than N2; and

(ii)

medium duty ties—

(A)

in areas where the design wind speed is more than N2; and

(B)

where engaged piers are provided; and

(b)

be spaced and fixed in accordance with Table 3.3.5.3a and Table 3.3.5.3b; and

(c)

be protected against corrosion in accordance with Table 3.3.5.4.

Table 3.3.5.3a Wall tie spacings

Maximum spacings

450 mm wall stud spacing

600 mm wall stud spacing

Horizontal

Maximum 450 mm centres

Maximum 600 mm centres

Vertical

Maximum 400 mm

Table 3.3.5.3b Placement of wall ties

Location

Placement of wall ties

Unsupported panel sides and edges of openings

Within 300 mm of panel side or edge

Top of veneer panels and top of panels under openings

Within 300 mm or two courses (whichever is the lesser) of the top of veneer

Bottom of veneer panel in masonry rebate sealed with liquid applied damp-proof course
Bottom of veneer panel supported on steel lintel

Within 300 mm or two courses (whichever is the lesser) from the bottom of the veneer

Bottom of veneer panel in masonry rebate with membrane damp-proof course

In each of the first two courses

Where articulation joints occur

At both sides of the articulation joint within 300 mm from the joint

Engaged piers

Within 200 mm of the top of the pier

Note to Table 3.3.5.3b: Ties are to be fixed to the supporting frame at all regular stud positions using screws or nails.

Table 3.3.5.4 Corrosion protection for wall ties

Exposure condition

Tie specification - minimum corrosion protection

Areas—

less than 1 km from breaking surf; or
less than 100 m from salt water not subject to breaking surf; or
within heavy industrial areas.

Grade 316L stainless steel; or
engineered polymer complying with the requirements of AS/NZS 2699.1.

Areas—

1 km or more but less than 10 km from breaking surf; or
100 m or more but less than 1 km from salt water not subject to breaking surf.

Sheet steel and bar ties galvanised after manufacture - 470 g/m² on each side; or
galvanised wire ties - 470 g/m² coating mass; or
Grade 304L stainless steel.

All other areas

Galvanised sheet steel - 300 g/m² coating on each side; or
sheet steel ties galvanised after manufacture - 300 g/m² on each side.

Explanatory information:

Wall ties that are suitable for use in a more severe exposure condition are also suitable for use in less severe exposure conditions, i.e. stainless steel and engineered polymer ties are suitable for use in all conditions and 470g/m² galvanised ties can be used in all exposure conditions except the most severe.

3.3.5.11 Openings in masonry veneer

(a)

Except where excluded by (b), openings in masonry veneer must be spanned by steel lintels.

(b)

Openings in masonry veneer not more than 500 mm wide need not be provided with a steel lintel provided the opening is adequately supported.

3.3.5.12 Lintels

Where a lintel is required it must comply with the following:

(a)

Steel lintels must comply with this Part or Part 3.4.4.

(b)

Steel lintels must—

(i)

be sized in accordance with Table 3.3.5.5; and

(ii)

be installed with the long leg of lintel angle vertical; and

(iii)

not carry more than a 110 mm thick veneer; and

(iv)

not carry masonry more than 3 m in height when measured above the opening; and

(v)

have a minimum bearing length at each end of the lintel of—

(A)

for clear spans not more than 1 m - 100 mm; or

(B)

for clear spans more than 1 m - 150 mm (See Figure 3.3.5.2); and

(vi)

have a minimum of three courses of masonry over openings; and

(vii)

comply with the corrosion protection requirements of Table 3.3.5.6.

Table 3.3.5.5 Masonry veneer lintel sizes

Lintel	Maximum clear span of lintel (mm): ≤ 600 mm of masonry over opening	Maximum clear span of lintel (mm) > 600 mm of masonry over opening
Flat 75 x 8	700	700
Flat 100 x 10	900	900
Angle 90 x 90 x 6EA	3000	2650
Angle 90 x 90 x 8EA	3200	2800
Angle 100 x 100 x 6EA	3350	2900
Angle 100 x 100 x 8EA	3600	3040
Angle 150 x 90 x 8UA	4200	3850

Note to Table 3.3.5.5: The lintels described in this Table must be not less than grade 300 MPa in accordance with AS 4100.

Table 3.3.5.6 Corrosion protection - Lintels

Durability class of lintel in accordance with AS/NZS 2699.3 ^{Note 1}	Material or protective requirements in accordance with AS/NZS 2699.3 ^{Note 1}
R1 R2	Hot dip galvanised with a minimum average coating thickness of 300 g/m²; or stainless steel 316L
R3	Hot dip galvanised with a minimum average coating thickness of 600 g/m²; or stainless steel 316L
R4	Stainless steel 316L

Notes to Table 3.3.5.6 :

AS/NZS 2699.3 contains information on the corrosivity category locations in Australia and provides a method for determining coating thickness for lintels.
Additional decorative coatings can be applied, but must not be considered for the purpose of satisfying the requirements of this Table.
Any lintel with a coating that is modified, i.e. by cutting, welding, or where damaged, must have the coating restored to provide an equivalent level of protection provided by the original coating.

Figure 3.3.5.2 Lintel installation

3.3.5.13 Vertical articulation joints

(a)

Vertical articulation joints must be provided in masonry veneer walls in accordance with (b), except in walls constructed on sites where the soil classification is A or S (see Part 3.2.4).

Explanatory information:

For the purposes of 3.3.5.13, the vertical articulation joint also performs the function of a contraction or expansion joint.

(b)

Articulation joints between masonry elements must have a width of not less than 10 mm and be provided (see Figures 3.3.5.3, 3.3.5.4 and 3.3.5.5)—

(i)

in straight, continuous walls having no openings - at not more than 6 m centres and within 4.5 m, but not closer than 470 mm of all corners; and

(ii)

in straight, continuous walls with openings more than 900 x 900 mm - at not more than 5 m centres and located so that they are not more than 1.2 m away from openings; and

(iii)

where the height of the wall changes by more than 20% - at the position of change in height; and

(iv)

where a wall changes in thickness; and

(v)

at control or construction joints in footings or slabs; and

(vi)

at junctions of walls constructed of different masonry materials.

(c)

Articulation joints must not be constructed adjacent to arched openings.

(d)

Articulation joints must either be filled with—

(i)

a compressible foam or polystyrene filler and a flexible sealant; or

(ii)

a purpose made backer rod and a flexible sealant (see Figure 3.3.5.5).

Figure 3.3.5.3 Example of vertical articulation joint locations in plan view

Figure 3.3.5.4 Vertical articulation joints

Figure 3.3.5.5 Vertical articulation joint details

Diagram a. Articulation joint with compressible foam and sealant

Diagram b. Articulation joint with backer rod and sealant

Note to Figure 3.3.5.5: Joints and sealants may be painted to reduce visual impact.

3.3.5.14 Engaged piers

Where engaged piers are installed to support subfloor framing, they must comply with the provisions of this Part and be constructed as follows:

(a)

Footings for piers must comply with Part 3.2.

(b)

Engaged piers must not support more than a single storey with a roof framing span of not more than 12 m.

(c)

Piers must be spaced at not more than 3 m centres with floor framing complying with—

(i)

Part 3.4.2 for steel framing; and

(ii)

Part 3.4.3 for timber framing; and

(iii)

Part 3.4.4 for structural steel framing.

(d)

Piers must be—

(i)

not more than 1.2 m high; and

(ii)

a minimum thickness of 100 mm inclusive of mortar; and

(iii)

a width greater than the depth of the timber or steel section which it is supporting (See Figure 3.3.5.6).

(e)

Notwithstanding (c), engaged piers must be located beneath—

(i)

each side of window and door openings; and

(ii)

concentrated roof loads, inclusive of any roof beams and girder trusses.

(f)

Piers must be tied or bonded to the external masonry wall, and where ties are used they must comply with 3.3.5.10.

(g)

Piers formed from hollow-core masonry units must be filled with grout.

Figure 3.3.5.6 Engaged pier

Filter

Part 3.3.5 Masonry veneer

Appropriate Performance Requirements

3.3.5.0

Acceptable Construction Practice

3.3.5.1 Application

3.3.5.2 Height of wall limitation

3.3.5.3 Masonry units

Explanatory information:

3.3.5.4 Mortar mixes

3.3.5.5 Mortar joints

3.3.5.6 Cavities

Explanatory information:

3.3.5.7 Damp-proof courses and flashings — material

3.3.5.8 Damp-proof courses and flashings — installation

3.3.5.9 Weepholes

3.3.5.10 Wall ties

Explanatory information:

3.3.5.11 Openings in masonry veneer

3.3.5.12 Lintels

3.3.5.13 Vertical articulation joints

Explanatory information:

3.3.5.14 Engaged piers