VENT-A-ROOF® - Specifying Fielders

VENT-A-ROOF® is the latest technology in roof ventilation for Fielders® steel roofs. VENT-A-ROOF® is a cost-effective, architecturally attractive solution for:

Commercial buildings
Light Industrial buildings
Residential homes
Sheds

VENT-A-ROOF® is a non-mechanical continuously operating, waterproof, cyclone-rated, metal roof ventilation system that provides a condensation management solution. Managing roof cavity condensation mitigates mould issues and contributes to improved health and safety in buildings across Australia.

Benefits of a VENT-A-ROOF®

Improves roof ventilation with continuous airflow, reducing both roof space temperature and energy costs associated with cooling the building
Full roof ventilation is made possible with both ridge and hip vents
Mitigates condensation, humidity and mould
Australian wind, bushfire and cyclone rated
Cost-effective and integrated into the roof providing a low profile attractive alternative to ventilators
Keep cooler in summer and remove condensation in winter
Certified for use in BAL 12.5 – 40 regions to prevent ember ingress at ridge and hips
Certified for use in cyclonic regions
DTC solution for 2019 NCC condensation management and roof ventilation requirements

How the system works

Figure 1.1

This deceptively simple passive system allows fresh outside air to be taken into the roof space either through soffit/eave vents or in through the system itself. This cooler air rises from these intake points and mixes within the ceiling or building space to create a natural flow of air that leaves the hot air escaping through the top of the ridge/skillion.

Simultaneously, external breezes provide a positive airflow which crosses over the ridge of the house creating negative pressure which pulls air out from the ridge vent. Effectively, two thermal effects create a continuous flow of air, allowing cool air into the roof/building space whilst extracting hot air.

This information is a guide to the design and installation of the VENT-A-ROOF® system for steel roofing and walling manufactured by Fielders®. We intend that it be used by all trades and professions involved with specifying and applying the VENT-A-ROOF® range of products.

We refer only to genuine steel roofing and walling manufactured by us and marketed under our brand names. Our recommendations should only be used for our products because they are based on comprehensive testing of our profiles, base metal thicknesses (BMT) and material finishes. More general design in installation with regard to steel cladding may be found in the Fielders® Roofing and Walling Installation Manual. This manual covers a range of topics not covered in this installation.

This information has been prepared for the VENT-A-ROOF® system for roofing applications using components manufactured or supplied by Fielders®.

Whilst this information primarily deals with VENT-A-ROOF® in roofing applications the principles apply equally to walling applications. For specific walling advise speak with your local Fielders® branch. VENT-A-ROOF® louvres are not recommended for use at wall bases where they may be subjected to constant moisture.

This page covers installation procedures for both new and retro fit applications in both non-cyclonic and cyclonic applications.

Material specifications

VENT-A-ROOF® steel vent components are manufactured from 0.4mm BMT aluminium/zinc/magnesium alloy coated steel.

Fielders® steel cladding and flashings are available in a range of materials and finishes including

Next generation ZINCALUME® aluminium/zinc/magnesium alloy coated steel complying with AS 1397:2011 G300, AM125 125g/m2 minimum coating mass.
COLORBOND® steel is pre-painted steel for exterior roofing and walling. It is the most widely used. The painting complies with AS/NZS 2728:2013 and the steel base is an aluminium/zinc alloy-coated steel complying with AS 1397:2011. Minimum coating mass is AM100 (100g/m2).
COLORBOND® Metallic steel is pre-painted steel for superior aesthetic qualities displaying a metallic sheen.
COLORBOND® Ultra steel is pre-painted steel for severe coastal or industrial environments (generally within about 100m - 200m of the source). The painting complies with AS/NZS 2728:2013 and the steel base is an aluminium/zinc alloy-coated steel complying with AS 1397:2011. Minimum coating mass is AM150 (150g/m2).
VENT-A-ROOF® louvres are not recommended for use with SuperDura™ Stainless steel

NCC roof space ventilation requirement V ventilation performance

Volume 1 of the National Construction Code (NCC) covering class 2-9 buildings (Non-Residential) outlines requirements for ventilation of roof spaces at;

Section F - Heath and amenity, Part F6 - Condensation management Performance requirements, Clause F6.4 – Ventilation of roof spaces (extract at Figure 2:1).

Similarly, Volume 2 of the NCC covering class 1 & 10 buildings (Residential) outlines ventilation of roof spaces at;

Section 3 - Acceptable Construction, Part 3.8 - Health and Amenity, Part 3.8.7 - Condensation Management, Clause 3.8.7.4 - Ventilation of roof spaces.

Roof ventilation requirements for both Residential and non-Residential buildings are similar in that where an exhaust system from a kitchen, bathroom sanitary compartment or laundry discharges into a roof space that roof space must be ventilated to outdoor air through evenly distributed openings.

The required ventilation openings must have a total unobstructed area of:

For roof pitch of greater than > 22 degrees - an unobstructed area of 1/300 of the ceiling area.
For roof pitch of less than < 22 degrees - an unobstructed area of 1/150 of the ceiling area.
At least 30% of the total unobstructed area must be located not more that 900mm below the ridge/hip with the remaining required area provided by eave vents.

Figure 2.1:

NCC Volume 1 Extract

F6.3 Flow Rate and discharge of exhaust systems
a) An exhaust system installed in a kitchen, bathroom, sanitary compartment or laundry must have a minimum flow rate of:
1. 25 L/s for a bathroom or sanitary compartment;
2. and 40 L/s for a kitchen or laundry
b) Exhaust from a kitchen must be discharged directly or via a shaft or duct to outdoor air
c) Exhaust from a bathroom, sanitary compartment, or laundry must be discharged:
1. directly or via a shaft or duct to outdoor air; or
2. to a roof space that is ventilated in accordance with F6.4.

F6.4 Ventilation of roof spaces
a) Where an exhaust system covered by F6.3 discharges directly or via a shaft or duct into a roof space, the roof space must be ventilated to outdoor air through evenly distributed openings.
b) Openings required by a) must have a total unobstructed area of 1/300 of the respective ceiling area if the roof pitch is greater than 22˚, or 1/150 of the respective ceiling area if the roof pitch is less than or equal to 22˚.
c) 30% of the total unobstructed area required by b) must be located not more than 900 mm below the ridge or highest point of the roof space, measured vertically, with the remaining required area provided by eave vents.

NCC residential Deemed-to-Satisfy Ventilation requirements (with eave vents) for Whirlybirds or VENT-A-ROOF®

				Linear metres of VENT-A-ROOF® required
Roof pitch	Ceiling area (m2)	No. of 300mm diameter whirlybirds	No. of 400mm x 200mm eave vents	Skillion ridge ventilation (lm)	Gable/hip ventilation (lm)
≤22°	100	3	7	22	11
	125	4	9	27	14
	150	5	10	32	16
	175	5	12	37	19
	200	6	14	43	22
	225	7	15	48	24
	250	8	17	53	27
	275	8	19	58	29
	300	9	20	64	32
	325	10	22	69	35
	350	10	24	74	37
	400	12	27	85	43
>22°	100	2	4	11	6
	125	2	5	14	7
	150	3	5	16	8
	175	3	6	19	10
	200	3	7	22	11
	225	4	8	24	12
	250	4	9	27	14
	275	4	10	29	15
	300	5	10	32	16
	325	5	11	35	18
	350	5	12	37	19
	400	6	14	43	20

NCC residential Deemed-to-Satisfy Ventilation requirements (with eave vents) for Whirlybirds or VENT-A-ROOF® provides a ready reckoner for a Deemed to Comply solution for both whirlybirds and VENT-A-ROOF® in both skillion and gable/ hip roof configurations utilising eave vents as part of the ventilation solution.

NCC residential Deemed-to-Satisfy Ventilation requirements (without eave vents) for Whirlybirds or VENT-A-ROOF®

				Linear metres of VENT-A-ROOF® required (No Eave Vents)
Roof pitch	Ceiling area (m2)	No. of 300mm diameter whirlybirds	Skillion ridge ventilation	Gable/hip ventilation
≤22°	100	10	71	36
	125	12	88	44
	150	15	106	53
	175	17	123	62
	200	19	141	71
	225	22	158	79
	250	24	176	88
	275	26	193	97
	300	29	211	106
	325	31	228	114
	350	33	248	123
	400	38	281	141
>22°	100	5	36	18
	125	6	44	22
	150	8	53	27
	175	9	62	31
	200	10	71	36
	225	11	79	40
	250	12	88	44
	275	13	97	49
	300	15	106	53
	325	16	114	57
	350	17	123	62
	400	19	141	71

NCC residential Deemed-to-Satisfy Ventilation requirements (without eave vents) for Whirlybirds or VENT-A-ROOF® provides a similar a Deemed to Comply solution for both whirlybirds and VENT-A-ROOF® in both skillion and gable/hip roof configurations where eave vents are unable to form part of the ventilation solution.

For residential buildings outside of the m2 range in the above tables, the calculation example below maybe used.

Calculation example for a “typical” residential building with bathrooms and kitchen exhaust vans venting into roof space.

House ceiling m2 = 250m2

Roof pitch = 22.5 degrees

Therefore,

250m2 ceiling area x requirement > 22 degree roof pitch i.e. 1/300 (0.003) = 0.833m2 of ventilated opening. This may be split 30/70 between ridge and eave vents

Therefore,

0.833m2 x 30% = 0.250m2 ridge vent

0.833m2 x 70% = 0.583m2 eave vents

Ventilation capacities

1m of VENT-A-ROOF® ridge provides 0.019008m2 of unobstructed area for ventilation.
Generally, a 300mm dia whirlybird (WB) provides an unobstructed area for ventilation of 0.07m2 ea.
A 400mm x 200mm eave vent (EV) will provide 0.08m2 of unobstructed area for ventilation.

Airflow Calculations

Single storey house	Wind Pressure Pa	Wind speed		External air temp differential to attic space air temp (degrees Celsius	300mm whirlybird		lm VENT-A-ROOF® louvre skillion ridge (with 45-50mm throat dimension)		lm VENT-A-ROOF® louvre Gable/ Hip Ridge (2m of louvre) (with 45-50mm throat dimension)		lm VENT-A-ROOF® louvre skillion ridge = 1x300mm whirlybird		lm VENT-A-ROOF® louvre gable/hip ridge (2m of louvre)
	Wind Pressure Pa	km/h	Knots		Airflow (m3/s)	Heat Extraction (kW	Airflow (m3/s)	Heat Extraction (kW	Airflow (m3/s)	Heat Extraction (kW	Airflow (m3/s)	Heat Extraction (kW	Airflow (m3/s)	Heat Extraction (kW
	0	0	0	6	0.019	0.137	0.006	0.046	0.013	0.091	3	3	1.5	1.5
				12	0.020	0.288	0.007	0.096	0.013	0.092	3	3	1.5	1.5
				18	0.021	0.454	0.007	0.151	0.014	0.302	3	3	1.5	1.5
				40	0.022	1.056	0.007	0.352	0.015	0.704	3	3	1.5	1.5
	2.0	6	3.2	6	0.029	0.206	0.01	0.069	0.019	0.138	3	3	1.5	1.5
				12	0.030	0.429	0.01	0.143	0.020	0.286	3	3	1.5	1.5
				18	0.031	0.677	0.01	0.226	0.021	0.451	3	3	1.5	1.5
	3.6	8	4.3	6	0.034	0.247	0.011	0.082	0.023	0.165	3	3	1.5	1.5
				12	0.035	0.5	0.012	0.167	0.023	0.333	3	3	1.5	1.5
				18	0.036	0.787	0.012	0.262	0.024	0.524	3	3	1.5	1.5
	8.0	12	6.5	6	0.051	0.37	0.017	0.123	0.034	0.246	3	3	1.5	1.5
				12	0.052	0.753	0.017	0.251	0.035	0.502	3	3	1.5	1.5
				18	0.053	1.137	0.018	0.379	0.035	0.758	3	3	1.5	1.5
	12.5	15	8.1	6	0.060	0.432	0.02	0.144	0.040	0.288	3	3	1.5	1.5
				12	0.060	0.871	0.02	0.29	0.040	0.58	3	3	1.5	1.5
				18	0.061	1.324	0.02	0.441	0.041	0.882	3	3	1.5	1.5
	14.2	16	8.6	6	0.063	0.456	0.021	0.152	0.042	0.304	3	3	1.5	1.5
	14.2	16	8.6	12	0.065	0.935	0.022	0.312	0.043	0.623	3	3	1.5	1.5

• Airflows represented for 0 km/h (Knots) wind speed are entirely due to convection.
• Increasing wind speeds will cool a sunlit roof hence reductions in attic v ambient temperatures for higher wind speeds.
• Bolded text represents default Australian design pressure of 12.5 Pa.

Airflow capacity/air exchange calculation example for a "typical" light industrial shed

Shed Dimensions

Length50m
Width                                                             18m
Wall height at eave                                      3m
Roof pitch                                                      5 degrees
Roof Apex height                                         3.790m
Wind speed Default design pressure       12.5pa or 8.1knots
External v internal air temp                       12 degrees – warm day

Calculation
Step 1 – Shed Air Volume

Air volume of shed = (50m x 18m x 3m) + (50m x 9m x 0.790m) = 2700 + 355.5 = 3055.5m3

Step 2 – Air Extraction RateFrom

Table 3 we can see that the Airflow/Air Extraction Rate per metre of louvre at the ridge given a 12 degree external to internal temperature variation and 8.1knts of wind = 0.040m3/s

Step 3 – Air Volume Extracted per Hour

0.040m3/s per metre of louvre

50m building length = 2m3/secondx

60 seconds = 120m3/minx

60 minutes = 7200m3/hr

Step 4 – Air Exchange Rate

Shed air volume = 3055.5m3
Volume extracted per hour = 7200m3

Therefore:
3055.5m3 divided by 7200m3/hr airflow provides for complete shed air changeover every .424 hours or every 25 minutes from the VENT-A-ROOF® system alone.
In practice, additional air changeover will occur via doorways, windows, shed wall to roof junctions etc.

VENT-A-ROOF® BAL (Bushfire Attack Level) performance

All new residential construction in Australia must undergo a BAL (Bushfire Attack Level) assessment as part of the building application process.
Properties are assessed against 6 Bushfire Attack Levels as outlined in the table below

Bushfire Attack Levels

Bushfire Attack Level (BAL)	BAL zone description
BAL Low	There is insufficient risk to warrant specific construction requirements
BAL – 12.5	Ember attack. (BAL 12.5 Construction Requirements) i.e. Non-combustible coverings roof/wall junction sealed. Openings fitted with non-combustible ember guards. Roof to be fully sarked
BAL – 19	Increasing levels of ember attack and burning debris ignited by windborne embers, together with increasing heat flux. (BAL 19 Construction Requirements) i.e. Non-combustible coverings roof/wall junction sealed. Openings fitted with non-combustible ember guards. Roof to be fully sarked
BAL – 29	Increasing levels of ember attack and burning debris ignited by windborne embers, together with increasing heat flux. (BAL 29 Construction Requirements) i.e. Non-combustible coverings roof/wall junction sealed. Openings fitted with non-combustible ember guards. Roof to be fully sarked
BAL – 40	Increasing levels of ember attack and burning debris ignited by windborne embers, together with increasing heat flux and with the increased likelihood of exposure to flames. (BAL 40 Construction Requirements) i.e. Non-combustible coverings roof/wall junction sealed. Openings fitted with non-combustible ember guards. Roof to be fully sarked and no roof mounted evaporative coolers
BAL – FZ	Direct exposure to flames from fire, in addition to heat flux and ember attack. (BAL FZ Construction Requirements) i.e. Roof with FRL of 30/30/30 or tested bushfire resistance to AS1530.8.2. Roof/wall junction sealed. Openings fitted with non-combustible ember guards. No roof mounted evaporative coolers

VENT-A-ROOF® has been independently assessed as suitable ridge and hip treatment to prevent ember ingress for BAL-12.5 – BAL – 40 zones

Fielders® steel cladding and ancillary products combustibility status are outlined in NCC compliance documents located at https://specifying.fielders.com.au/roofing-walling/design-data/statement-of-compliance-for-fielders-roofing-walling-and-rainwater-goods/

VENT-A-ROOF® cyclonic performance

Air leakage testing conducted at Farabaugh Engineering and Testing, show that VENT-A-ROOF® assists pressure equalisation between internal and external pressures. Testing results as shown in the below table, demonstrate that a greater volume of air “escapes” through the VENT- A-ROOF® system than what is let in, an approximate 8% difference. The results show that as the test pressure increases, the rate of air escaping through the VENT-A-ROOF® system increases.

NB Test results Infiltration = air exiting the roof cavity and Exfiltration = air entering the roof cavity. (Nielson, 2019)

Test Pressure

		Infiltration		Exfiltration		Ratio (%)
Test Pressure (Psf)	Test Pressure (Pa)	Air leakage rate (Cfm)	Air leakage rate (m3/s)	Air leakage rate (Cfm)	Air leakage rate (m3/s)	Infiltration	Exfiltration	Difference (m3/s)
1.57	75.17	44	0.020765688	37.5	0.017698029	54%	46%	0.003067658
6.24	298.77	86.1	0.040634675	74.5	0.035160085	54%	46%	0.00547459

Based on these results, it is determined that installation of the VENT-A-ROOF® system to ridgeline areas of metal clad roofing to residential and commercial properties, will reduce internal pressures and as such reduce structural loads to these structures during cyclonic and high wind events. (Nielson, 2019)

VENT-A-ROOF® has been independently assessed and certified as suitable for use in cyclonic regions when affixed in accordance with the VENT-A-ROOF® Design and Installation Guide for cyclonic regions.

Step 1 - Roof Sheeting Installation

Install Fielders® S-Rib™, Fielders® TL-5™ or Fielders® KingKlip®700 sheeting in accordance with installation details available on this website.
Critical dimensions for roof ridge batten position and ridge throat dimensions are shown at Figure 3.1.1.

Figure 3.1.1

Fielders® Roll Top Ridge

	Dimensions (mm)
	Batten			Sheet	Throat	Ridge
	Apex ridge to toe of batten			Sheet overhang top of batten	Sheet to sheet	Ridge legs
	15˚	22.5˚	25˚			Toe	Step/Raise	Pan
State	A			B	C	E	F	G
NSW	175	165	160	95	60-55	17.5	25	106






VIC	175	170	165	90	55-50	17.5	25	102



TAS	175	170	165	90	55-50	17.5	25	102

SA	165	155	150	91	30-17	12	22	91

WA	170	160	155	95	50-45	20	25	99

Figure 3.1.2

Fielders® Folded Ridge

	Dimensions (mm)
	Batten			Sheet	Throat	Ridge
	Apex ridge to toe of batten			Sheet overhang top of batten	Sheet to sheet	Ridge legs			Feed width
	15˚	22.5˚	25˚	Sheet overhang top of batten	Sheet to sheet	Toe	Step/Raise	Pan	Feed width
Region	A			B	C	E	F	G	(mm)
Non cyclonic	180	175	170	95	55-65	22	25	150	400
Cyclonic	205	200	195	95	100-110	22	25	175	45

Figure 3.1.3

Fielders® Folded Ridge (Commercial applications)

	Dimensions (mm)
	Batten			Sheet			Throat	Ridge
	Apex ridge to purlin edge			Sheet overhang top of Purlin			Sheet to sheet	Ridge barge legs			Feed width
	1˚	5˚	15˚	1˚	5˚	15˚		Toe	Step/Raise	Pan
Application	A			B			C	E	F	G	(mm)
Commercial/Industrial	173			95		110	140-180	22	25	200	500

Figure 3.1.4

Skillion Roof Ridge/Apron

	Dimensions (mm)
	Batten			Sheet	Throat	Ridge Barge/Apron
	Apex ridge to toe of batten			Sheet overhang top of batten	Sheet to sheet	Ridge barge legs
	15˚	22.5˚	25˚	Sheet overhang top of batten	Sheet to sheet	Toe	Step/Raise	Pan	Wall side
Region	A			B	C	E	F	G	H
Non cyclonic	190	185	180	95	40-35	25	25	150	75
Cyclonic	240	235	230	95	90-85	25	25	200	75

It is important that a consistent line is maintained at the ridge line of sheeting as per the dimensions noted in Figure 3.1.1-3.1.4 and the above tables as appropriate. Do not screw fix the ridge line of roof sheets. Sheet pans should not be turned up.

Step 6 - Install ridge cap

Install ridge cap in accordance to AS 1562.1 using screws recommended at Specifying.Fielders.com.au Screws should penetrate ridge, VENT-A-ROOF® louvre, roof sheet and batten below providing fixing to both roof ridge and ridge cap.

No scribing is required with VENT-A-ROOF® louvre, due to the closed cell weather tight foam within the VENT-A-ROOF® louvre.

For applications where only the ridge portion of the roof is utilising VENT-A-ROOF® the VENT-A-ROOF® ridge will sit 25mm above the hips caps. This will allow the VENT-A-ROOF® roll top ridge to neatly marry to the hip roll top ridge as shown in Figure 3.6.1.

Please note that for South Australian applications utilising roll top ridge that some pressure is required to “spread” the roll top ridge to cover the VENT-A-ROOF® louvres and maintain ridge throat dimension.

Hip install

The same principles apply to installation of hips with critical dimensions being identical.

Screw pattern

Cyclonic and Non Cyclonic

Louvre fixing screw pattern - Cyclonic and Non Cyclonic applications

		Fielders®
Sheet Type	S-Rib™	TL-5™	KingKlip®700	Screw
Recommended spacing of VENT-A-ROOF® fixing screws	1st and last sheet rib			10 - 16 x 16mm Teks®
	then every 4th rib	then every 2nd rib	then every rib
Distance from front/bottom edge of VENT-A-ROOF® louvre	60mm
Distance from top edge of VENT-A-ROOF® louvre	25mm
Fixing spacing at VENT-A-ROOF® joints	Both sides of join
Spacing of ridge cap fixing screws	Every 2nd rib	Every rib	Every rib	As per Fielders® published data for roof sheeting
	for cyclonic applications cyclonic zips should be used for ridge cap fixing screws

Step 1 - Determine replacement ridge flashing dimensions

Remove a small number of screws from a portion of the exist ridge to allow measurement from the ridge screw line (and mid-line of existing batten) to the top of the existing sheets.

Compare the measured dimensions with those in Table 6 to determine if roll top ridge or a special folded ridge is required.

Measure and order ridge lengths and VENT-A-ROOF® louvres.

Step 2 - Remove existing ridge

Remove the portion of the existing ridge to be replaced by the VENT-A-ROOF® system to expose the ridge throat.

Step 5 – Install VENT-A-ROOF® louvres

Start laying VENT-A-ROOF® louvres, left to right, as per 3.2 through to 3.10 of new installation instructions following appropriate screw patterns.

Step 6 – Install new ridge flashings

Following guidelines from 3.10 cut and screw fix new ridge flashings to vented ridge.

Step 7 – Clean up

Clean all debris from roof paying particular attention to swarf from cutting of sheets and screw installation.

Step 8 – Install eave vents

Install 400mm x 200mm eave vents, if required, in accordance with manufacturer’s instructions.

Fielders® operations have been servicing Australia’s residential, industrial and commercial construction industries for over 115 years. Fielders® unique and innovative products, first class engineering and testing resources as well as a strong commitment to quality customer service and support make them leaders in metal roll-forming manufacture and supply.

Our products are engineered to perform according to our specifications only if they are used in the appropriate conditions and installed to the recommendations in this information and our other publications.

Naturally, the warranties require specifiers and installers to exercise due care in how the products are applied and installed and are subject to final use and installation. Also, owners need to maintain the finished work. The VENT-A-ROOF® system will not negatively impact warranties applicable to Fielders® products.

We invite you to ask about the warranties applicable to your proposed purchase, at your supplier of Fielders® products.

If you use this information, you acknowledge and agree that your use is subject to the terms and conditions in this information. Fielders®, its agents, officers, employees, sub-contractors or consultants make no representations, either expressed or implied, as to the suitability of the information and data in this page for your particular purposes.
It’s your responsibility to ensure the design you use is appropriate for your needs, the products you have purchased, your site and structural limitations and your building and construction capabilities.

This information endeavours to present information on products, details, installation and practices in a clearly prescribed manner and it is the user’s responsibility to apply the information in the way intended. If there is any uncertainty then it is the user’s responsibility to seek clarification.

Where we recommend use of third-party materials, ensure you check the qualities and capabilities of those products with the relevant manufacturer before use.

Use of genuine materials

Structures in this information should only be built or constructed using genuine Fielders® or recommended third party products. Except as otherwise provided in these terms, any warranties only apply to you (if at all) if you use the recommended genuine Fielders® or third-party products and method of construction.

Check delivery

It is important that you check all materials delivered to site against your invoice before you use them in your building or construction to ensure all components have arrived, are of the appropriate quality and are ready for installation.

Introduction

Benefits of a VENT-A-ROOF®

How the system works

Figure 1.1

Design Preliminaries

Materials and finishes

Material specifications

NCC roof space ventilation requirement V ventilation performance

Figure 2.1:

NCC residential Deemed-to-Satisfy Ventilation requirements (with eave vents) for Whirlybirds or VENT-A-ROOF®

NCC residential Deemed-to-Satisfy Ventilation requirements (without eave vents) for Whirlybirds or VENT-A-ROOF®

Airflow Calculations

Airflow capacity/air exchange calculation example for a "typical" light industrial shed

VENT-A-ROOF® BAL (Bushfire Attack Level) performance

Bushfire Attack Levels

VENT-A-ROOF® cyclonic performance

Test Pressure

Installation - New Installations

Step 1 - Roof Sheeting Installation

Figure 3.1.1

Fielders® Roll Top Ridge

Figure 3.1.2

Fielders® Folded Ridge

Figure 3.1.3

Fielders® Folded Ridge (Commercial applications)

Figure 3.1.4

Skillion Roof Ridge/Apron

Step 2 - Begin VENT-A-ROOF® louvre install

Step 3 - Slide louvre over sheet

Step 4 - Fix louvre to sheet

Step 5 - Add additional louvres

Step 6 - Install ridge cap

Hip install

Figure 3.6.1

Screw pattern

Louvre fixing screw pattern - Cyclonic and Non Cyclonic applications

Installation - Retro-Fit

Step 1 - Determine replacement ridge flashing dimensions

Step 2 - Remove existing ridge

Step 3 - Mark roof sheets to be cut

Step 4 - Cut back the sheets

Step 5 – Install VENT-A-ROOF® louvres

Step 6 – Install new ridge flashings

Step 7 – Clean up

Step 8 – Install eave vents

Warranties

Appendices

FORM 15 – BAL-12.5 – 40

FORM 15 Australian wind regions A 1-7, B, C & D

JCE A150 - Letter of advice - VENT-A-ROOF® product

Performance test summary TAS-100A on EZ VENT-N-CLOSURE for VENT-A-ROOF®

Performance test report ASTM E283 leakage test on metal roof vent for VENT-A-ROOF®

Conditions of use

Use of genuine materials

Check delivery

Airflow Calculations