BUILDING CODE

E2/AS3

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External Moisture Acceptable Solution E2/AS3The Building Code clause for External Moisture (E2) requires that buildings

must be built to resist leaks, damp or the accumulation of external moisture in

concealed spaces.

E2/AS3 is a supporting document to the Building Code clause for External Moisture.

E2/AS3 is a new solution for weathertight concrete and concrete masonry

construction. This solution provides one way of complying with the Building Code

clause for External Moisture.

E2/AS3

introduced on

1 August 2011

What does the new solution cover?

E2/AS3 is effective now. It is included in Amendment 5 of the E2 External Moisture

Compliance Document which can be downloaded from

www.dbh.govt.nz/compliance-documents.

E2/AS3 references the new Code of Practice for Weathertight Concrete and

Concrete Masonry Construction published by the Cement and Concrete Association

of New Zealand, which can be downloaded free or purchased as hard copy from

www.ccanz.org.nz.

Acceptable Solution E2/AS3 is effective 1 August 2011

E2/AS3 can be used for houses and small non-residential buildings, up to three

storeys and less than 1000 m2 floor area. Outbuildings, retaining walls and basement

walls are not covered.

Weathertight systems are provided for:

• Concreteslabs-on-groundandfootings

• Concreteandconcretemasonrywalls

• Concreteflatroofsanddecks

• Windowanddooropenings

• Junctionsbetweenwalls,roofsandfloors

• Junctionsbetweenconcreteandtimberconstruction.

E2/AS3 makes compliance simpler for weathertight concrete and concrete masonry design, allowing a greater range of building materials.

Want to know more? www.dhb.govt.nz/compliance-documents

BUILDING CODE

E2/AS3

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Weathertight Systems:

Slab-on-ground and footings

• Dampproofmembranes(DPM)comprisingbituminoussheetorpolythenecanbeused. DPM requirements are based on NZS 4229, section 7.

Walls

• Threetypesofwallconstructionarecovered-insituconcrete,precastconcreteand concrete masonry.

• Fiveweathertightnesssystemsarecoveredasindicatedinthetablebelow.

• Weathertightdetailsforcontroljoints,windows,doors,pipepenetrations,meterboxes,junctionswithtimberwallsandjunctionswithtimberroofsareprovided.

Weathertightness System

EIFS Plaster Systems Masonry Veneer

Coating Systems Watertight Concrete

Polymer based Plaster

Polymer modified Cement Plaster

3 coat Solid

Plaster

Pigmented elastomeric high build

Acrylic (>_180µm)

Pigmented Acrylic

(>_80µm)

Clear Coating

Concrete masonry walls ✓ ✓ ✓ ✓ ✓ ✓ ✗ ✓ ✗

In situ concrete walls ✓ ✓ ✓ ✗ ✗ ✓ ✓ ✓ ✓

Precast concrete walls ✓ ✓ ✓ ✗ ✗ ✓ ✓ ✓ ✓

Wall Weathertightness Options

Insulation is shown in the wall and roof details in E2/AS3, and is located either internally, integrally, or externally (ie, EIFS).

Insulation is not required to comply with E2, but can be used as shown in E2/AS3 without compromising weathertightness.

Insulation in Walls and Roofs

BUILDING CODE

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What is an Acceptable Solution (AS)?

An Acceptable Solution details one way to comply with the relevant part of the BuildingCode.Ifyoufollowthesolutiondescribed,yourbuildingworkwillmeetthatpart of the Building Code.

Flat roofs and decks

• EPDMorbutylrubbermembranesorbituminousmembranescanbeused.

• AcceptableEPDMandbutylrubbermembranesaresimilartoE2/AS1.

• AcceptablebituminousmembranesarebasedontheCodeofPracticefor Torch-onMembraneSystemsforRoofsandDecks– http://metalroofing.org.nz/frontend/index.cfm.

• Weathertightnessdetailsaregivenforparapets,roofpenetrationsand doorthresholdstodecks.

Want to know more? www.dhb.govt.nz/compliance-documents