ducting for extractor

[colw1]

hi I have three ducts to go in in the loft for the main bathroom and two en suite , all of these ducts I want to run to the soffit but what I would like to know is if you can run all three toghter and out of one vent or at least two. Finally do I need any special equipment to get it in the soffit and what is best the white 100mm pipe or the silver

 

[muggles]

I suppose technically you could have them all joined together, but you'd need to join them before the extractor fan or the air will just suck out of one room and blow into another, unless all the extractors are running simultaneously, which is a little energy inefficient if only one is needed.

I'm not sure whether you can get Y connectors for the ducting though, I suppose it's possible but you might find that if you're running three in to one you'll need a larger 6" fan and 6" final duct run to the soffit. The wiring might get a bit interesting if you've got to get the fan running off two or three seperate light switches in seperate rooms...very much a question for the sparkys. In fact, extractors generally are very much a question for the sparkys, head off to the Electrics UK board and ask them