extraction fans in flat roofed house?

[fixa24]

Howdy folks
I have purchased a flat roof house, and intend on conducting bathroom and kitchen renos..
The question i have is, i wish to install one of those licht/heat/fan thingos, but one box i read said not suitable for flat roofed houses..
is there any that are?
is my only option a wall mounted extraction fan?
TIA.
Simon.

[Skew ChiDAMN!!]

Dunno, but on one job I was called in to fit shortish vertical ducts for the sparky to install ceiling-mounted extraction fans into a flat roof. The ducts were galvanised, a bit less than a metre long, same diameter as the fan, with capping on top to prevent weather entry.

I've no idea how well they worked as I left before the sparky hit the site. It may be worth your looking into though.

[Sybarite]

I think the main reason the packaging would have specified that the product as not suitable for flat roofs is so that certain types of people dont cut holes in their flat roofed ceilings and install these heater/extractors fush against rooflining, or worse, cut a hole straight through to the outside...
In my experience these units are often installed to vent directly into a roof space rather than being ducted externally - indeed many designs are not really conceived with ducting in mind.
Having said this, if you can install a fan in a ceiling in such a manner that it can vent freely and remain protected from elements/vermin (as suggested above) I can't see why it can't work for you.

Ducts!

Regards.

[silentC]

We installed a couple of these in a flat roof. Used a short bit of flue with a china man's hat on top. They work fine. Only downside is that you lose heat through the flue, but that's OK because the heat from those lamps is radiant and it's not going to heat up the room much in the short time they are switched on.

[fixa24]

Thanks for the info guys..
i don't think i'll worry too much about heat loss.. i live in north QLD!
hadn't thought of a duct... what about one of those spinny extraction things?

[silentC]

Western Rotary Vent? Nah, I don't think you need one of those. You just need something to keep the rain out. There are a few different styles. I just had my BIL make me a chinaman's hat. The type of thing you might see on top of a heater flue if you ever head south

[fixa24]

Cheers!
will give it a go...
now to work out the wiring!

[Markw]

Installed one of these when I reno'd the kitchen. There are various types on the market and most are designed for a particular type of exit point. Having a pitched roof mine goes up the wall into the ceiling cavity then across and out through the eaves in a small vent. The other alternative for the one I purchased was for it to go vertical with a vent cap as said by Silent.

There are other types around that if you have the stove against an external wall you should be able to exit through the wall.

One thing you need to do is get it out of the roof space. The amount of cooking gunk that they can collect is a lot - from the condensed smoke from frying or grilling. You dont want to attract a mouse or rat colony let alone feed the cockroachs.

BTW most of these units require that you fit a 10a power point (GPO) above the main funnel area next to the vertical flue cover or even up in the ceiling space - depending on how the system exits. Mine is in behind the stainless flue cover. Check with the manufacturer prior to purchase if you have special requirements.