Roof Vent

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E3xtc

770 posts

Ultimate Geek

#136182 18-Nov-2013 09:43

Hey all,

We have a colour steel roof and am interesting in finding out what is involved in getting a roof vent installed so that any humid air can escape - the roof is above the garage (with the man hole being in the garage), so when wet hot cars come and park it gets very humid, so just wanting to help ensure the roof space above is nicely vented.

Any ideas?

Cheers
Troy

Stan

929 posts

Ultimate Geek
Inactive user

#936630 18-Nov-2013 14:03

Would like to know the answer to this as well. I wonder if you could get it made though a sheet metal fabricator that does flue kits etc?

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BlueShift

1692 posts

Uber Geek

#936633 18-Nov-2013 14:04

Wouldn't you be better off with some vents at the top of the walls under the eaves? Much less chance of wind driving rain in where its not wanted.

E3xtc

770 posts

Ultimate Geek

#936695 18-Nov-2013 15:15

That is an option (easier to do myself I suppose), but was thinking the whole hot (humid) air rising etc - so thought it would be better to have the vent near the peak of the roof?
*shrug*

mattwnz

20035 posts

Uber Geek

#936700 18-Nov-2013 15:19

You may need to check with your council if you are installing something in the roofing material, as to whether you need consent first. Venting the roof is a good idea, especially if you have condensation problems. However a metal roof should have a lot of gaps in it to naturally ventilate it. It is usually membrane type roofs that you get a problem with.

gregmcc

2131 posts

Uber Geek

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#936707 18-Nov-2013 15:27

you can buy a product called a spinaway, basically cut a circular hole, screw it to the roof, seal with silicon, adjust the angle of the spining bit to keep it horizontial, lock it in place with a screw.

As the hot air in the roof rises it escapes thru the spinaway which spins, it should draw the moisture out as you are getting the movement of air as it vents

spinaway

mattwnz

20035 posts

Uber Geek

#936712 18-Nov-2013 15:33

gregmcc: you can buy a product called a spinaway, basically cut a circular hole, screw it to the roof, seal with silicon, adjust the angle of the spining bit to keep it horizontial, lock it in place with a screw.

As the hot air in the roof rises it escapes thru the spinaway which spins, it should draw the moisture out as you are getting the movement of air as it vents

spinaway

They are pretty ugly though, unless you have it behind a parapet. You often seen warehouses with those. I have seen ridge flashings with vents built in which look better, and you then rely on normal stack ventilation when high air rises. With spinning ones, if you are relying on silicon, it will potentially be a source of leaking if not done properly or overflashed properly. People should never rely on silicon with roofing.

E3xtc

770 posts

Ultimate Geek

#936716 18-Nov-2013 15:37

while the concept of the spinaway seems functionally good - I hate the idea of having something on the roof that will be spinning around potentially creating noise/vibration/etc. It does look very industrial too :(

mattwnz

20035 posts

Uber Geek

#936840 18-Nov-2013 18:32

What about something like this vented ridge flashing http://steelandtube.co.nz/product/pur/publications/design/vent-ridge

E3xtc

770 posts

Ultimate Geek

#937106 19-Nov-2013 07:06

yeah that could be the ticket - something that sort of looks part of the roof, with passive ventilation (rather than something sucking or moving the air around). Now I suppose with that in mind I should maybe have a chat to a roofer :)

andrewNZ

2487 posts

Uber Geek
Inactive user

#937128 19-Nov-2013 08:26

Does the roof have a gable end/s? a vent there would sort it.

E3xtc

770 posts

Ultimate Geek

#937135 19-Nov-2013 08:33

nope - no gable end, so assume it needs to be something mounted onto the roofing finish itself.

andrewNZ

2487 posts

Uber Geek
Inactive user

#937144 19-Nov-2013 08:49

Can't garantee the legitimacy of this place, but it has some ideas

http://www.gafroofing.co.nz/download/gafelk%20vents.pdf?inline

E3xtc

770 posts

Ultimate Geek

#937155 19-Nov-2013 09:15

nice - some interesting products there

E3xtc

770 posts

Ultimate Geek

#937236 19-Nov-2013 12:07

if anyone is interested - I have spoken to the people at the NZ Roofing association and there is a code of practice for metal roofs that touches on ventilation - you can find this at metalroofing.org.nz