Australia Wind Roofing Classification

7/27/2019 Australia Wind Roofing Classification

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CSR ROOFING ARCHITECTURAL MANUAL

The design o a Tiled roo and iTs supporTing sTrucTure requires careul

consideraTion, involving undersTanding o a number o building sTandards.

one o The key responsibiliTies o The speciier is To deTermine The design gusT

wind speed aecTing a parTicular siTe.

design


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conTenTs

design consideraTions 1

wind caTegories 2

Terrain caTegories 5

ixing requiremenTs or Tiles and accessories 6

edge Technology ixing speciicaTion 10

raTer lengTh and spacings 11

baTTen sizes and raTer spacings 12


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designconsideraTions

The installation specications given in this

manual are based on a basic wind speed

or ultimate strength o 74m/s at a height

o 6m rom ground level. This is suitable

or sites in Regions A, B and New Zealand.

For installation specications or designated

cyclonic areas i.e. Regions C and D it is

also advisable to consult both your building

engineer and your local CSR Roong oce.

This section will cover CSR Roongs

recommended installing specications

based on the design gust wind speed, as

well as:

Minimum roo pitch requirements

Maximum rater length requirements

Rater and truss spacings and batten

requirements

Batten installing requirements

Sarking/underlay installation

requirements

Please note that relevant local authorities

may apply special specication to the

nal structure. Speciers are advised

to determine local requirements beore

proceeding.

Furthermore, regional CSR Roong oces

may recommend additional installing

specications based on experience o a

particular region, so it is also advisable to

consult your local CSR Roong oce prior

to commencement o work.

To acilitate this, the Australian Standards AS

1170.2, AS 4055 and NZS 4203 are to be

considered, regarding:

The regional design wind speeds

The terrain category o a building site

The Technical Record 440 (TR440)

extension o this code, which is

deemed to be the standard or design o

products or most cyclonic areas

This is particularly applicable inAustralia to areas north o the latitude

250 south, and within 50kms o the

coast (including o shore islands).

Local requirements and covenants

determined by State and/or local

statutory authorities. Special conditions

may apply to the site in relation to

items a), b) and c)


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wind caTegories

Winds and the pressure they create,

must be considered when speciying roo

structures and roong materials.

The negative pressure exerted to the leeward

side o a pitched roo at 35m/s can be

greater than the weight o the tiles, thereore

determining the wind orce aecting a

site at height is essential to identiy theappropriate level o security installation.

The magnitude o these wind orces is

aected by the ollowing actors:

Basic wind speed, Direction, Terrain and

Building height.

Basic wind speed categoriesAS 1170.2/Amdt 3 and AS 4055 provides

inormation on wind speeds generally

aecting dierent regions o Australia.

r b

r c

r b(ausTralian TerriTory only)

r b

r b

r d

r c

r c

r c

r a4

r a1

r a5(wiThin 70km

o melbourne gpo)

r a3

r a2

lord howe islandregion a

norolk islandsregion bcorindi

brisbaneToowoomba

kyogle

bourke

bundaberg

rockhampTon

biloela

collinsville

Townsville

aTherTon

dunbar

cairns

mareeba

moreTonmcdonnell creek

142

11

burkeTown

wesT moreland

borroloola

adelaideriver

kununurra

alice springs

ivanhoe

darwin

wyndham (c)

broome

porT hedland

croydonkarraTha

onslowmarble bar

millsTream

gascoyne JuncTion

callyTharra

mullewa

morawakalgoorlie

gunyidi

perThesperance

albany

greenhead

carnarvon

woomera

adelaidecanberra

geelong70kmmounT gambier

sydney

hobarT

sTaTe border

50km

easT sale

200km

20

25

35

40

45

30

35

30

25

20

27

a3

r t t tta [a1 t a5], b, c d.

ct r t t t t 50, 100, 150 200.

i t 50 t t t r t jt t.

r a

non-cyclonic classiicaTion

r b r c r d

cyclonic classiicaTion

chrisTmas islandregion b

cocos islandregion c

ausTralia

negaTive pressure (sucTion) leeward side

regions v(m/s)

a 41

b 49

c 57

d 69

regions v(m/s)

a 50

b 60

c 70

d 85

regions v(m/s)

a 38

b 38

c 45

d 50


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* NZS 4203 General Structual

Design and Design Loading or

Buildings provides inormation on

wind speeds generally aecting

dierent regions o New Zealand.

For urther inormation on Wind

Loads in New Zealand reer to NZS

4203 General Structual Design

and Design Loading or Buildings.

kaiTaia

whangarei

auckland

morrinsvillehunTly

hamilTon

new plymouTh

ohakuna

waiouruwanganui

palmersTon norTh

Tauranga

roTorua

gisborneTaupo

napier

waipawa

waipukurau

upper huT

wellingTonnelson

wesTporT bienheim

hammersprings

hokiTika

haasT

milord sound

cromwell

alexandra

invercargilldunedin

Twizel Timaru

meThven

chrisTchurch

culverden

kaikoura

r a6

r a7

r wr a7

44

37

dt t t t t tt .

s : 012

souTh easT wind

ot : 1230

s : 012

ot : 1230

norTh wesT wind

lee mulTiplier, m

new zealand


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Based on the Wind Class

specication provided, CSR Roong

is able to assess the appropriate

level o security installation required

or the roo in accordance with AS

2050 Installation o Roo Tiles.

Wind Classication system N1, N2,

N3, N4, N5, N6 or non-cyclonic

Regions A and B, and C1, C2, C3

and C4 or cyclonic Regions C and

D shall be considered. The system

includes the combinations o

regions, terrain categories, shielding

o housing and topographic eects

given in Table 2.

It is the speciers responsibility to

determine the wind speed aecting a site

and a house design. In other words to

determine the Wind Class o a regional area

combined with the Wind Speeds aecting

a site. Cyclone aected regions will have a

Wind Class rom C1 to C4. For non-cyclonic

regions, a Wind Class rom N1 to usually

N4 is required to be specied on your

roong structure plan.

The table below summarises the

relationship between the Wind Speeds and

the Wind Class.

taBle 1: design wind speed equivalent values/as 4055

wind caTegory km/hor non-cyclonic

regions a and b

or cyclonic

regions c and d

design gusT wind speed

(m/sec) permissible

sTress meThod only

w28 101 n1 28

w33 119 n2 33

w41 148 n3 c1 41

w50 180 n4 c2 50

w60 216 n5 c3 60

w70 252 n6 c4 70

taBle 2: wind classification system (refer as 4055)region Terrain

caTegoryTopographic classiicaTion

T1

s ps ns

T2

s ps ns

T3

s ps ns

T4

s ps ns

T5

s ps ns

a Tc 3 n1 n1 n1 n2 n2 n2 n2 n3 n3 n2 n3 n3 n3 n3 n4

Tc 2.5 n1 n1 n2 n2 n3 n3 n2 n3 n3 n3 n3 n4 n3 n4 n4

Tc 2 N1 N2 N2 n2 n3 n3 n3 n3 n3 n3 n4 n4 n4 n4 n4

Tc 1 n2 n3 n3 n3 n3 n4 n3 n4 n4 n4 n4 n4 n4 n5 n5

b Tc 3 n2 n2 n3 n3 n3 n4 n3 n4 n4 n4 n4 n4 n4 n5 n5

Tc 2.5 n2 n3 n3 n3 n4 n4 n3 n4 n4 n4 n4 n5 n4 n5 n5

Tc 2 n2 n3 n3 n3 n4 n4 n4 n4 n5 n4 n5 n5 n5 n5 n6

Tc 1 n3 n4 n4 n4 n5 n5 n4 n5 n5 n5 n5 n6 n5 n6 n6c Tc 3 c1 c1 c2 c2 c2 c3 c2 c3 c3 c3 c3 c3 c3 c4 c4

Tc 2.5 c1 c2 c2 c2 c3 c3 c3 c3 c3 c3 c4 c4 c4 c4 na

Tc 1, Tc 2 c2 c2 c2 c2 c3 c3 c3 c4 c4 c3 c4 c4 c4 na na

d Tc 3 c2 c3 c3 c3 c4 c4 c3 c4 c4 c4 na na na na na

Tc 2.5 c2 c3 c3 c3 c4 c4 c4 na na c4 na na na na na

Tc 1, Tc 2 c3 c3 c4 c4 na na c4 na na na na na na na na

FS ull shielding PS partial shielding

NS no shielding N non-cyclonic

C cyclonic N/A not applicable


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Terrain caTegories

the four terraincategories are:Terrain Category 1

Zo= 0.002M

Exposed open terrain with ew or no

obstructions, in which the average

height o objects surrounding the

structure is less than 1.5 metres.

This category includes water

suraces (open sea coast and lakes),

fat and treeless plains, and open

snowelds.

Terrain Category 2

Zo= 0.02M

Open terrain, grassland with ew

well-scattered obstructions having

heights generally rom 1.5 to 10.0

metres. This category includes

open parkland and sparsely built up

outskirts o towns and suburbs.

Terrain Category 3

Zo= 0.2M

Terrain with numerous closely

spaced obstructions having the size

o domestic houses. This includes

most suburban areas.

Terrain Category 4

Zo= 2.0M

Terrain with numerous large,

high (10.0 to 30.0 metres) and

close obstructions, such as large

city centres and well-developed

industrial complexes.

terrainThe shielding provided by permanent

structures, hills and vegetation has the

eect o modiying wind speeds.

Terrain categories are used or determining

a sites exposure to wind. In Australia,

terrain is dened in accordance with AS

1170.2 and AS 4055 into our categories.

In NZ, the relevant standard is NZS 4203.

For the eective use o this tool, the

direction and speed o wind fows towards a

site must be assessed.

0.000

0.002 Natural snow surace (fat)

0.006 Desert (stones)

0.008 Cut grass (10mm)

0.02 Rough open water suraces

at wind speeds (Vu) and (Vp),

Isolated trees, uncut grass and

airelds

0.04 Crops

0.06 Few trees

Long grass (600mm)

0.2 Level wooded country,

Suburban buildings

0.4 Centres o small towns

0.8 High density metropolitan

1.0 Forests

2.0 City buildings (10.0m to 30.0m)

roughness length (2)m


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ixing requiremenTs orTiles and accessories

taBle 3: as2050 minimum mechanical installing requirements for tiles and ancillaries

wind classiicaTion Tile insTalling ancillary insTalling

edge o roo ield o roo ridge, hip and barge Tiles

u t

n2 n1 n2

m t t t

t t

tt

m t t

u t n3 c1 m t

t

m t

t

m t t

n4 c1/c3 m t

t

m t

t

m t t

taBle 4: as 2050 wind classification and maXimum design gust wind speed

wind classiicaTion maximum design gusT wind speed (m/s)

permissable sTress

meThod (vp)

serviceabiliTy limiT

sTaTe (vs)

ulTimaTe limiT

sTaTe (vu)

n1 28 (w28n) 26 34

n2 33 (w33n) 26 40

n3c1 41 (w41n/c) 32 50

n4c2 50 (w50n/c) 39 61

c3 60 (w60c) 47 74

Note: Wind classifcations are as defned in AS 4055

taBle 5: australian mechanical requirements for tiles and accessories

design windvelociTy (m/s)

Tile ixing ridge ixing barge ixing

edge o roo ield o roo ridge Tiles hip ridge Tiles

u t t t

< 33

m f t t 2

t t 2 t

, t 2

m f

t.

m f

t.

m f

t.

> 34 < 41 m f

t 2

m f

2 t

m f

t

m f t

t.

m f

t.

> 41 < 60 m f

t

m f

t

m f

t

m f

t.

m f

t.


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taBle 6: new zealand minimum fiXing requirements for tiles and accessories

design wind velociTy(m/s)

Tile ixing

edge o roo/body

o roo

ridge & hip ixing barge ixing

low wind speed

u t 32 /

m f t

2 t t

2 t ,

t 2

a

t

m f

t

medium wind speed

u t 37 /

m f t

2 t t

2 t ,

t 2

a

t

m f

t

high wind speed

up To 44 m/s

m f t

2 t t

2 t ,

t 2

a

t

m f

t

very high wind speed

u t 50 /

m f t a

t

m f

t

speciic engineering

designo 50 /

p t r

csr rf of

p t r

csr rf of

p t r

csr rf of

Note:

Accepted methods o mechanical fxing are specifed later in this manual.

CSR Roofng recommends the use o Flexible Pointing as standard or all roos, removing the need or other orms o mechanical fxing. Flexible Pointing also provides

other signifcant benefts reerred to later in this manual.

Please consult your regional CSR Roofng ofce or their specifc recommendations.

taBle 7: australian fiXing recommendations

windclass

sarking/underlay

securiTy pads mechanicallyix Tiles

mechanicallyix eave Tiles

anTi-pondingboard

ixingbody and edgeo roo

n1 ot

t

ot

ot ot

r

t 20

jt t tt

ft

s t 3

n2

r

n3

mt

f as

4200.2

n4

mt r

c1

c2

c3


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taBle 8: new zealand fiXing recommendations

wind class underlay mechanically ix Tiles

mechanicallyix eave Tiles

anTi-pondingboard

ixing body &edge o roo

l ot

t

r

t 200s T 6

m r

t 200s T 6

h r

t 200s T 6

v h mt r

t 200s T 6

Denotes recommendation

minimum roof pitchCSR Roong tiles are designed and tested

to cope with the diverse range o wind and

weather conditions across Australia and

New Zealand.

The ollowing actors aect the design o

your roo:

the roof tile selectionWith a proled roo tile, the depressions

in the body o the tile act as a natural

watercourse, enabling water to be

channelled down the roo quickly.

For fatter proled tiles, these depressions

are either less prominent or do not eature.

As a result, water is reer to be pushed

across the roo surace by wind. The eect

is that water migrates to the watercourse o

the tile.

the pitch of the roofThe greater the pitch, the greater the orce

o gravity combined with wind orce to pull

water rom the roo.

Conversely, the lesser the pitch, the lesser

the orce o gravity combined with wind

orce to pull water rom the roo.

For this reason, tiling is not recommended

below 15 degrees without special

precautions being taken in direct

consultation with your regional CSR Roong

oce. Indeed, AS 2050 states where

it is intended to x tiles to roos with a

pitch o less than 15 degrees, the tile

manuacturers advice should be sought.

Sarking/underlay is a pliable oil installed

prior to xing the roo battens.

In New Zealand underlay is a sel

supporting building paper. Not only does

sarking/underlay act as a secondary water

catchment, sarking/underlay also aids with

keeping your home cooler and dust ree.

There are several diering grades o

sarking/underlay, it is recommended that

you consult with your local CSR Roong

representative who can assist you with the

correct application to suit your particular

design.

Table 9 indicates the minimum roo pitch at

which CSR Roong tiles are to be installed,

with and without the need or sarking/

underlay, or each region.


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9

SECTION3

TABLE 9: MINIMUM ROOF PITCH DEGREES

MINIMUMPITCH

NSW VIC QLD SA WA(SURROUNDING

PERTH)

NZ CYCLONEAREA

MONIER

CONCRETEWithout

Sark

With

Sark

Without

Sark

With

Sark

Without

Sark

With

Sark

Without

Sark

With

Sark

Without

Sark

With

Sark

Without

Sark

With

Sark

Without

Sark

With

Sark

Elabana 20 15 20 15 20 15 20 15 20 15 20 15 # 17.5

Centurion 20 15 20 15 20 15 20 15 20 15 20 15 # 17.5

Tudor 20 15 20 15 20 15 20 15 20 15 na na na 17.5

Waverley 20 15 20 15 20 15 20 15 20 15 na na na 17.5

Homestead 20 15^ 20 15^ 20 15^ 20 15^ 20 15 na na na 17.5

Traditional 20 15^ 20 15^ 20 15^ 20 15^ 20 15 na na # 17.5

Georgian 20 15^ 20 15^ 20 15^ 20 15^ 25 22.5 na na # 25

Cambridge 20 15^ 20 15^ 20 15^ 20 15^ 25 22.5 na na # 25

Horizon 20 15^ 20 15^ 20 15^ 20 15^ 25 22.5 # 25 # 25

Madison 20 15^ 20 15^ 20 15^ 20 15^ 25 22.5 na na # 25

WUNDERLICH TERRACOTTA

Modern

French

20 15 20 15 20 15 20 15 20 15 25 20 # 17.5

Nouveau 20 15 20 15 20 15 20 15 20 15 25 20 # 18.5

Marseille 20 15 20 15 20 15 20 15 a a 25 20 # 17.5

Nullarbour # 25 # 25 # 22.5 # 25 # 22.5 # 25 # 25

Heritage

Shingle*# 25 # 25 # 25 # 25 # 25 # 25 # 25

# Sarking/underlay required regardless of pitch

Anti ponding boards are required for pitches less than 20 deg and in cyclone areas

Consideration must be given to rafter length, site exposure and terrain category when determining roof pitch

^ Refer to EDGE technology xing specication

* Longer lead times and minimum order quantities apply Not all proles available in all states, check availability with your local sales ofce

Maximum rafter lengths apply, refer to Table 10, page 11 in Section 4.

na not available


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edge Technologyixing speciicaTion

monier roof tiles treated with edge technology*

edge technologyMoniers breakthrough EDGE Technology is a patented process that now oers architects

and designers greater fexibility when it comes to contemporary roo design. EDGE

technology has been comprehensively eld tested, and has also undergone rigorous wind

tunnel testing to endure product perormance exceeds AS 2050-2002. Additionally,

successul testing has also been conducted at Laarges world class acility in London England.

product specificationThis xing specication is to be used when installing Monier roo tiles that have been

treated with Moniers Patented EDGE technology. Available in selected states.

product rangeHorizon, Georgian, Cambridge, Madison

sarking/underlayMandatory or all pitches below 20 degrees. Additional consideration must be given to

locations that are elevated, or in coastal regions with our exposed to high wind speeds.

minimum roof pitch15 degrees with sarking/underlay.

At the minimum roo pitch o 15 degrees, the maximum rater length is 4.5metres.

For longer raters lengths add 2 degrees to the pitch or every addional metre.

head lap100mm or all pitches below 20 degrees.

I sarking/underlay is used at 20 degrees , a head lap o 80mm is permissible providing the

terrain category is not less than T2.5.

fiXingNailing is required or wind speeds up to N2.

Cyclone clips are required or wind speeds o N3 or more.

generalSpecial Consideration should be given to regions prone to cyclonic activity. Alternate xing

methods may need to be adopted. Reer these enquiries to the technical support team.

*Not available in all states


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raTer lengThand spacings

rafter (truss) spacingsThe wider the rater spacing, the

greater the stresses upon them, and

the batten specied.

Battens made o timber should

be sound, and in sucient length

and size to meet regional xing

requirements. Batten sizes and

types vary by region, however must

be xed in accordance with the

AS 1684 or AS 1720.1 and NZS

3604 in New Zealand.

rafter lengthconsiderationsCSR Roong tiles are designed

to be dimensionally consistent,

allowing some tolerance to assist

the roo tiler during set out.

However, it is advisable to consider

the rater length at the design stage,

to avoid the need to cut a short tile

course.

rafter lengthWith heavy rainall, a considerable volume

o water can accumulate at the bottom o a

roo. The longer the roo run (rater length),

the more water accumulates.

AS 2050 states long rater lengths may

require sarking/underlay to preventinundation o water into the roo. These

lengths may vary according to the tile, the

pitch o the roo and the exposure.

CSR Roong advises against the use o

minimum pitch or long rater lengths

without sarking/underlay. As a general guide

or contoured tiles, rater length should not

exceed 4.5m at a minimum pitch o 15

degrees. For every 0.5m increase in rater

length above 4.5 metres, the pitch should

increase by 1 degree until the acceptable

pitch o 22.5 degrees is reached or long

raters.

Table 10 indicates the rater length

dimensions at which sarking/underlayshould be installed over the aected roo

area. Advice should be sought rom your

local CSR Roong oce with regard to

regional sarking/underlay installation

requirements.

taBle 10: pitch levels in relation to rafter lengthmaximum raTer lengTh (mm) roo degrees o piTch

4500 15

5000 16

5500 17

6000 18

6500 19

7000 20

7500 21

8000 22

1.

000

RATIO 1: 1.

000

1.

250

1.

500

1.

750

2.

000

2.

250

2.

500

2.

750

3.

000

3.

250

3.

500

3.

750

4.

000

4.

250

4.

500

4.

750

4.

000

rise and run chartPitch expressed as a ratio o rise to run.

Equivalent pitch in degrees is a close approximation only


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baTTen sizes andraTer spacings

The ollowing table summarises suitable batten types at varying rater spacings, with the current CSR Roong practice in each region.

taBle 11: Batten sizes and rafter spacings (mm)

baTTen maTerial speciicaTion

raTer spacing up To 450 451600 601900 9011200

n st w h 38 25 h 25 50 h 38 50 mt T 40

st 38 28 st 38 38 st 50 50

st 63 38

mt T 40

vt h 38 25 h 25 50 h 38 50/38 38 h 38 75

st 38 28 st 38 38 st 50 50 mt T 40

mt T 40 mt T 40

q h 38 25 h 25 50 h 38 50 h 50 50

st 38 38 st 40 50 mt T 40

mt T 40

st at h 38 25 h 25 38 h 38 50 h 50 75

mt T 40 st 50 50 mt T 40

mt T 40

wt at h 38 25 h 38 25 h 38 38 h 50 50

st 38 38 st 63 38

mt T 40 mt T 40 mt T40

T h 38 25 h 25 50 h 38 50 h 50 75

st 38 38 st 50 50 mt T 40

mt T 40 mt T 40

at ct

Tt

h 38 25 h 25 50 h 38 50 h 50 50

st 38 38 st 63 38 mt T 40

mt T 40

n z st 25 50 st 40 50 st 50 50 st 50 75*

mt T 40 mt T 40 mt T 40*

Green font denotes the recommended and commonly used batten specifcation in each region.

* With engineer approval

Where metal battens are used reer to the batten suppliers fxing specifcation.

Australia Wind Roofing Classification

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Transcript of Australia Wind Roofing Classification