1.2 Design Information

1.2.1. Parapets

All parapets must be capped using a specified metal flashing, side fixed and installed with a minimum 5° slope.

Rockcote Systems considers parapets a non-maintainable area. This is defined as an area(s) which are not readily or easily accessible for general maintenance requirements by the property owner.

E2/AS1 : reference paragraph 4.6 – Flashings overlaps and upstands.

Situation 1

Low or medium wind zones, where roof pitch is 10 degrees or greater = 50mm cover over vertical wall surface is required.

Situation 2

For all roof pitches in high or very high wind zones, for all wind zones where roof pitch is less than 10 degrees = 70mm cover over vertical wall surface is required.

For extreme wind zones 90mm minimum cover is required.

Metal cappings offer a practical solution to waterproof perimeter and parapet walls. When they are installed then a 5 degree slope must be created so that any water is shed from the capping. Occasionally staining might appear down the face of a wall where a metal capping is installed. This is caused by dirt and dust settling on top of the parapet and when it rains it runs down both the front and rear faces of the parapet. By forming a slope back onto the roof for parapets this can be avoided. It is important that when fixing a capping that the fixings are through the side of the capping and not through the top. When detailing parapets make sure that any internal gutters have adequate fall and that any overflow units are positioned so that if there is a block in the guttering that the overflows will operate correctly.

E2/AS1 : reference section 6.0 – Parapets

1.2.2. Saddle Flashing

A flashing used to weatherproof the junction between a horizontal and vertical surface; i.e. Balustrade to main wall.

It is the roofer or main contractor’s responsibility for installing the appropriate flashings and tapes according to E2/AS1.

E2/AS1 : reference section 7.42 and 6.41

1.2.3. Kick-out / Apron Flashing

A single fold applied to the edge of a horizontal metal flashing to deflect moisture away from the cladding system below. A kick-out is used at the bottom of a capping or other flashing to deflect water away from the cladding below.

It is the roofer or main contractor’s responsibility for installing the appropriate flashings and tapes according to E2/AS1.

E2/AS1 : reference section 5.0

1.2.4. Fascias and Barges

It is the roofer or main contractor’s responsibility for installing the specified fascia / gutter systems to allow for accurate cladding installation according to E2/AS1, and Rockcote Systems technical manual

E2/AS1 : reference section 5.0

1.2.5. Ground Clearances

It is important that ground clearances are maintained after completion and occupation of the building, with the exterior ground sloped to carry water away from the exterior walls.

E2/AS1 Figure 65 and Table 18 Finished floor level

For masonry brick veneer wall claddings:

100 mm if ground is permanently paved (from finished floor level), or 150 mm if ground is unpaved (from finished floor level).

eg. If a cladding extends 100mm past the finished floor level than 25mm clearance to a paved surface must be maintained (provided the adjoining ground falls away to 150mm). If a cladding extends 50mm past the finished floor level than 100mm clearance to a unpaved surface must be maintained.

For cladding other than masonry brick veneer:

150 mm if ground is permanently paved (from finished floor level), or 225 mm if ground is unpaved (from finished floor level).
Claddings must extend a minimum of 50mm past the bottom plate.

eg. If a cladding extends 50mm past the finished floor level than 100mm clearance to a paved surface must be maintained. If a cladding extends 100mm past the finished floor level than 100mm clearance to a paved surface must still be maintained.

Garage floors

Need to be low enough to drive onto and high enough to provide a minimum 50 mm step-down to exterior paving, while maintaining cladding clearances either side of the garage door. To achieve this it may be necessary to construct the garage floor lower than the floor level of the building.

In these situations, providing a ’nib‘ at garage doorways allows the cladding to continue in a straight line while maintaining minimum clearances at the bottom of wall cavities for ventilation.

E2/AS1 : reference section 9.1.3 and Figure 65 and Table 18

It is the landscaper or other external contractor’s responsibility for ground level compliance in relation to cladding clearance and that ground clearances are maintained after completion and occupation of the building.

Decking Clearances / Level thresholds

35mm minimum clearance at the highest point of the deck to the cladding is required.

E2/AS1 : reference section 7.0

1.2.6. Balustrades and Handrails

Enclosed balustrade

A timber-framed barrier with cladding across all exposed faces. Enclosed balustrades can either be capped with metal flashings (refer to Rockcote TradeSpec™ document 1.2.1 Parapets), or alternatively liquid reinforced membrane i.e. Rockcote Vector5 waterproofing system (Refer to Rockcote TradeSpec™ document 3.3 Liquid Reinforced Membrane3.3).

Rockcote Systems considers enclosed balustrades as maintainable areas. This is defined as an area(s) which are readily or easily accessible for general maintenance requirements by the property owner.

E2/AS1 : reference section 7.4

1.2.7. Soffits

Soffits offer protection to the wall, that parapets do not. Soffits will protect the wall from the majority of water that would otherwise hit the wall if you were to use parapets.

1.2.8. Air Seals

A continuous seal fitted between a window or door reveal and the surrounding wall framing to prevent the flow of air into the interior of the building.

Air sealing ensures variations in pressure between the exterior and interior of a building will not cause air flow through these junctions, as this can drag water in behind the cladding.

After the joinery has been installed a PEF Backing Rod is inserted to the perimeter of the reveal, followed by the installation of low expansion foam. The PEF Backing Rod prevents excess foam entering the trim cavity, which has the potential of defeating the purpose of ‘pressure equalisation of the trim cavity’.

Air sealing also has energy efficiency benefits whereby the warm or cool internal air is not lost through gaps around the joinery, minimising the energy required to heat or cool a residence.

E2/AS1 reference : Airseals paragraph 9.1.6

1.2.9. Control Joints

for more information about control joints refer to TradeSpec™ Document 1.4 – Control Joints

1.2.10. Inter-storey drainage joints

Rockcote cavity based systems may be continuous up to two storeys or 7m maximum but not more, due to limits on drainage and drying.

If the wall is greater than two storeys or 7m high, divide the cavity using a horizontal flashing that bridges the cavity. Provide ventilation to the cavity above the junction, as completed for the base of the wall.

It is the builder’s responsibility for the supply and installation of the horizontal flashing according to E2/AS1.

Refer to E2/AS1 Paragraph 9.1.9.4.

1.2.11. Dissimilar substrates junctions

Multiple cladding junction installations must be considered at the design stage, to ensure accurate back-flashing and trade co-ordination occurs. A general rule of thumb is to back flash all dissimilar junction with a metal flashing and PEF Backing rod and sealant should be applied between the two substrates.

1.2.12. External Penetrations – Other Trades

Service penetrations such as, but limited to; joinery, plumbing, light fixtures, electrical conduit, must be sealed and finished by associated sub-trade prior to cladding installation.

Penetrations must be back-flashed against the building underlay / building wrap prior to cladding being installed.

Any penetration installed after the cladding has been applied is considered an alternative solution and documentation supporting this method of installation must be provided to the B.C.A for approval.

Confirm that exterior wall openings and penetrations have been prepared ready for the installation of the Rockcote System.

Where electrical cables must pass through conduit. Ensure that there is no direct contact with polystyrene when this substrate is selected.

Refer to E2/AS1 Paragraph 9.1.9. Penetrations

1.2.13. Coastal Zones / Geothermal Zones / Durability

In all corrosive zones Rockcote ventilated starter tracks and head flashings require stainless fixings due to potential for corrosive salt/geothermal vapour entering the cavity. Please check with Section 4 of NZS3604:2011 as to what zone your project is located in.

Where the cladding is non structural (i.e. offering no bracing elements) then a Galvanised screw/nail can be used in all zones. For more information please refer to NZS3604:2011 Section 4.4

1.2.14. Wind Zones

Wind Zones can affect the spacing of the nails as well as increase the risk to the design of the house consult with your local BCA to determine what Wind Zone you are in.

1.2.15. Insulation – over timber or steel framing

TradeSpec™ Document 1.5 – Insulation Methods