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Results 1 to 15 of 17
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26th January 2007, 11:32 AM #1
Intermediate Member
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- Aust
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Colourbond Roofs- Placement of Whirlybirds - Cosmetic considerations
Greetings
I was wondering what peoples opinions were on where whirlybirds should be positioned. I understand they must be as high as possible near the ridge capping to vent all possible air. (Halfway down may still result in the ridges corroding ??)
But cosmetically where would you place them?
I assume on the back (non street facing) sections of your roof? so as to only see a nice flat expanse of sheeting and valleys from the street.
Do any homeowners or roofing tradies have opinions on what theyve done or would do?
Cheers
Dale
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26th January 2007, 11:50 AM #2
New Member
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- Jan 2007
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- Frenchs Forest NSW
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- 3
Whirlybirds
Hi Dale
I know from experience that halfway down the roof on the side sheltered from the prevailing wind doesn't work (rarely spins). I would place them on the back of the house for purely cosmetic reasons. I would also place them sufficiently high that they just show above the ridge.
From recollection there is some guidance that comes with the product in the installation directions.
I think that the direction of the wind could be a significant factor.
Fred.
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26th January 2007, 12:06 PM #3
Dale
As Fred says they need to be as near to the ridge as possible to catch the wind. They certainly need eaves vents to work efficiently.
They can be bought in all the colorbond colours to match the roof and in the end who looks up at a roof and says "Those ventilators look terrible on the roof" Just doesn't happen and they would add to the value of the house because it would be one more thing that people wouldn't have to buy if the house was for sale.
Don't understand your comment about the ridge corroding.
If you do a search on the forum whirly birds have been discussed pretty extensively.
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26th January 2007, 12:30 PM #4
If you are using more than 1, I would put them on alternating sides of the ridge cap.
Cheers
DJ
ADMIN
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26th January 2007, 12:58 PM #5
Hi Dale,
I always put the whirly bird up the top of the roof and slide the flashing under the ridge capping. That reduces the risk of it leeking in the future plus the whirly bird works at its full potential as it isnt blocked by any wind disturbance.
Thanks...MarkWhen I die, I want to go peacefully like my Grandfather did, in his sleep---not screeming, like the passengers in his car.
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26th January 2007, 01:07 PM #6
I put multiple 'birds in. They don't need any breeze to work, they just use convection to remove heat from the roof cavity. They do work better if you have a cavity in the wall (like a double bricked house) as they suck they warm air up past the walls and drag cool air into the cavity. I have them at the rear of the house near the ridge capping.
Note though, that you need to be able to stop them in winter, you actually dont want any air movement in your walls or roof over winter.There was a young boy called Wyatt
Who was awfully quiet
And then one day
He faded away
Because he overused White
Floorsanding in Canberra and Albury.....
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26th January 2007, 09:55 PM #7
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26th January 2007, 11:15 PM #8
Scooter,
You can buy caps for them. You unscrew the whirlybird and replace it with a metal cap which seals the hole. Can be a problem however if you have a few whirlybirds as they have to be marked well to make sure that the right ones goes back on the right hole.Have a nice day - Cheers
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27th January 2007, 12:59 AM #9
Intermediate Member
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ridgecap vents vs whirly birds and thanks
Hi there
Thanks for the suggestions, I believe right near the ridgeline but on the non street side is the best combination cosmetically and functionally.
However what about using these ridgecap vents which of course are less obtrusive and I assume it would be possible to place them along nearly all of the ridge lines if you wanted to? Does anyone know of any data that proves which system is more effective?
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27th January 2007, 05:42 AM #10
SENIOR MEMBER
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- Apr 2005
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- Sydney
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I suppose that it's a matter of taste, but I'd rather look at a whirlybird than have that thing on my ridge.
Roll cap looks nice, and even nicer when it's pop riveted instead of screwed down with those big obtrusive roofing screws.
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28th January 2007, 12:38 AM #11"If you need a machine today and don't buy it,
tomorrow you will have paid for it and not have it."
- Henry Ford 1938
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28th January 2007, 09:59 AM #12
At the end of the day who looks up at a roof and says "Those screws look terrible why didn't they use a nice pop rivet"
I think you would find that when standing on the ground looking up at the screws and they were colour matched you wouldn't even notice them and that would be deviating from good building practice.
As Mick says it is a requirement in cyclonic areas in fact I think pop rivets would be challenged by any council inspector.
One of the areas looked at after Cyclone Tracey was the most susceptible areas on a roof during high winds was the cappings and flashings. This was the first area to go on a roof because of inadequate fixing, this then opened the roof up to the ingress of wind and the rest of the roof followed the flashing and cappings blowing into the neighbours back yard.
When you look at AS1170 on Wind Forces the highest pressures on a roof in high winds is at the ridge and the edges so this is where your best fixing should be.
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28th January 2007, 11:59 AM #13
More about ridgecaps
Don't know how it's done elsewhere, but up here the screws that hold down the ridgecap go down through the top of the roofing sheet and into the top batten. They're a tie down requirement, usually 12 gauge type 17 screws, 50mm long for custom orb, 65mm for trimdek.
Mick"If you need a machine today and don't buy it,
tomorrow you will have paid for it and not have it."
- Henry Ford 1938
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28th January 2007, 12:11 PM #14
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28th January 2007, 12:16 PM #15
SENIOR MEMBER
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I do.
Well I haven't built anything north of the border, and I haven't been picked up for not installing cyclone bolts here in Sydney either.
A roofing mob that used to do our metal roofing always used pop rivets on capping and all the jobs passed inspection, and they looked good to me. I don't know if he was being dodgy or not, but he did it for the looks, not for time or money saved.
As to whether they're required by the code or not, I couldn't say. As for good building practice, you could put your screws in every orb of every batten and that would be excellent building practice as far as cyclones go. Just depends on how much work and money you want to spend I suppose.