Thread: roof ventilators ( house )

Originally Posted by waynep

Thanks for the replies guys, much appreciated ... I knew ther'ed be a wealth of knowledge on this.... us LR owners like "alternative" solutions to things ....
a lot to read through there I'll have to print it out and go through it all.

couple more questions leading from your comments :

1. these are the type of extractors I have bought http://www.edmonds.com.au/html/produ...ator_250mm.htm
the instructions say if you have a non-sarked tile roof there is no need to put the vents in the eaves because enough air comes through the gaps in the tiles. Is that true ?

2. we have downstairs a double brick basement that is hafl undergound and stays really cool in the summer ( in fact we sleep down there when it gets really hot. ). My theory in putting in the ceiling vents was to perhaps draw some of the cooler air from downstairs in to the main living area upstairs. Would that work ?

3. Our upstairs is brick veneer. The inside plaster has the wall vents up near the ceiling. Now I heard that those vents actually let hot air in from the space between the bricks and the plaster, and you can now legally block them up. Is that true ?

Wayne, this house sounds like it has the same layout as ours, 3 b/rooms upstairs with a spare room and luandry downstairs, we also sleep downstairs if its too hot upstairs. In regards to tiles, what does sarked mean ?

Originally Posted by loanrangie

Wayne, this house sounds like it has the same layout as ours, 3 b/rooms upstairs with a spare room and luandry downstairs, we also sleep downstairs if its too hot upstairs. In regards to tiles, what does sarked mean ?

I'm no builder but I beleive sarking is the stuff they put directly under the tiles. It used to be a bitumeous paper but these days its more like a aluminium coated paper. I believe it is supposed to stop the condensation from the tiles dripping on to the ceiling ? Any roofers / builders on here will correct me I'm sure. As far as the ventilation part goes, if you've got sarking then no air can flow in between the tiles and out through the ventilators, therefore you need to install vents under the eaves.

Yes your place sounds exactly like our setup.

Originally Posted by waynep

i've bought a couple of those whirly gig roof extractors to put on the house roof and try and vent the roof space and keep the inside house temps down over summer.

Just wondering if anyone has any advice on where to position these on the roof. Its an L-shaped house with tile roof ( non sarked )

I also bought a couple of the ceiling vents ( ones you can open and shut ) . .where should i put these in relation to the roof extractors .....ie right under them or across ways a bit ?

we don't have aircon at the moment just seeing if these ventilators and sun blinds keep the house cool enough to avoid installing it.

I have four of them, evenly spaced out accross the ridge line of the roof.
I also have about 10 airvents in the eaves so the hot air is drawn out of the roof cavity. On top of that, the top of the ceiling is also covered with "space age foil" (bubble wrap with silver on either side).

The result, roof cavity is a lot cooler, house is a hell of a lot cooler in summer and TOO cool in winter.

Originally Posted by 4bee

Wayne, to me that would be a bad move as you will then heat up your cool oasis which will then need to cool down again. While that is happening, assuming that the weather doesn't get hotter, you won't have the benefit of the Oasis.

It will also depend on whether soil behind the walls is up against the walls (unlikely) or open as a vented to outside & therefore ambient temperature storage area.

Hmmm good point.

so it looks like I need the eave vents then ...gotta get some of those.

I think i'll still install the 3 internal ceiling vents /registers I bought, then I can open them up in the evening to assist with cooling down of the house ( venting the hot air up through the roof )

..gonna be interesting ti see how much difference this makes ... i'll report back.

I will be fitting a couple of whirly gigs next weekend as well, i dont have anything under the tiles at all but i think a few well spaced vents in the eaves will help. I have rolls of insulation foil that i thought of stapling to the under side of the roof bearers.

i think i'll still install the 3 internal ceiling vents /registers i bought, then i can open them up in the evening to assist with cooling down of the house ( venting the hot air up through the roof )

It just shows there ain't nothing new in the world.

You just reminded me, Wayne.

Back in the days of olde when I did my Refrigeration Apprenticeship (& later Air Cond) I purchased an Audels Refrigeration & Air conditioning Guide AKA 'The Bible', & not because it just looks like one either.

In it, it describes the design & installation of "Attic Fans". (USA 1949)

In a 2 storey house there was located in the upstairs ceiling, a couple of grilles open to the living area. Connected to those by ductwork was an electric motor driven centrifugal fan.

The plan was that as the evening ambient temperatures outside fell, one opened all the windows in the house & fresh, & supposedly cool air was drawn through all night.

Come daybreak, the windows were shut & windows closed. Repeat nightly as necessary.



Btw, if you want to know how to air condition a Pullman Railway Car or build a cork insulated Butcher's Ice Box or air condition your Cargo Ship, let me know. I'm your man.



Dunno why the Caps haven't worked. ?????????

I've wondered about roof vents myself. Is there a way in winter that you can shutdown the whirly doover or close off the exit hole.

They'd help you'd save cooling costs in summer but you would not want them to increase heating costs?

Yes, you could do what they do with Evap Coolers. Tie a plastic cover or UV plastic bag over them.

When I first mentioned this the bloke said all he did was put a long screw through it to stop it rotating.

But I think you would still want them to ventilate the roof space ONLY, in Winter, as Kitchen & Bathroom exhaust fans normally discharge into the roof space & they would assist in reducing the build up of excess moisture.