bathroom extraction shared vent?

[caz26]

Hi, we've put in an en-suite and would like to know whether we can link the new extractor into the existing 4"pipe in the attic that goes out through the roof?

Or do we have to get the roofer out to pop another hole in the roof for each fan?

Sounds simple I know, is there any regs or just good advice to say yeah or nae.

Thanks, Caz

 

[ColJack]

if one fan is running and the other isn't then you'll get "blowback" into the other room with the fan.

if you fit an inline fan in the roof, then you can use it to do both rooms i should think.. though the controlls would be a bit of a pain to sort out..

 

[daytona]

you can def use an inline fan to control both rooms through the one duct.
you will need to double pole it all though to stop the light in the other room being backfed by the one your using.
its a little tricky but no big deal really.
basically all your doing is taking two switchlines to the fan but from the switches not the lights.then you fit double pole pullswitches/plateswitches.
dont forget the isolator and size the fan properly,just incase it stalls in the roof space and you dont notice,it will then be a fire hazard as the power will still be running to the motor,but no air will be drawn over it to keep it cool

EDIT:
when i say double pole,i mean double pole switches but with two switchlines.not a switchline and a neutral