Roof tile vent with hose ducting - for circulation or extract?

[dilalio]

morning all.

I am refurbing two shower rooms in a property and this includes changing the extractor fans in both. When up in the loft I discovered both existing flexi PVC ducts were just draped over a baton and venting into the loft space.

At three locations in the loft there are roof tile vents with black corrugated ducting protruding into the loft at almost eaves level. Are these for air circulation in the loft or should the bathroom extractors have been connected to them? Perhaps more important - can I hook up to them for extraction? Or should I provide separate outlet to the outside?
The loft spaces are an addition to the original house as part of an extension several years ago.

Many thanks for any information and guidance.

D.

 

[datarebal]

If they are what I think they are, they are for extract purposes.
They sound like adapters from the back of vent slate/tiles.. just never connected

 

[dilalio]

Cheers @datarebal that is what I suspected but didn't want to compromise natural roof draught/ventilation!

Would a photo help confirm they are for extract?

Edit: and if they are for extract how is condensation in the ducting best avoided? Create a trap with it or just continue with an incline from the ceiling vent location?

 

[^woody^]

Three down by the eaves would suggest that they were fitted for ventilation purposes.

 

[dilalio]

But I need to know a definitive use of the fitting not a suggestive one - wadr

 

[datarebal]

a picture would be good.
if they are for venting then they would not need the adaptors.
low level because ease of fitting.
either way you need to get the damp air to the outside rather than in the roof space..

 

[^woody^]

But I need to know a definitive use of the fitting not a suggestive one - wadr

They are definitely venting if there is no extract fan connected to them.

 

[dilalio]

Having looked at a couple of roof vent products online and also a couple YouTube vids, it looks like products such as Ubbink supply the ducting adapter (black ribbed hose) as an optional extra to their standard roof tile vent.

Would it be reasonable to assume that, as these extras have been purchased and fitted, and are in situ, that their intended use was for extract and some lazy arse employee just didn't bother to connect them up?

 

[John D v2.0]

I thought you needed a definitive use of the fitting not a reasonably assumptive one!
If so you need to calculate the ventilation requirements of the roof, based on the condensation risk analysis and nature of the membranes, then check the existing eaves ventilation to find the equivalent area, then see whether the vents in question are needed or not.
The building regs don't specify that if there's a bit of plastic attached then you should connect the extractor fan! Could just as much be incorrect ordering as incorrect fitting.
PS don't use flexi hose for extractor fans if possible.

 

[dilalio]

I think I'll take the advice of a roofer... which is why I posted in this forum.
Are you a roofer? A plumber? A bathroom fitter?

 

[John D v2.0]

Nope just have common sense and a little experience. I spent a good few minutes helping you so it's a shame you seem to throw it back at me. I'm sure someone will be along in a minute to tell you exactly what you want to hear

 

[dilalio]

Nope just have common sense and a little experience. I spent a good few minutes helping you so it's a shame you seem to throw it back at me. I'm sure someone will be along in a minute to tell you exactly what you want to hear

Point taken and I do appreciate your time, so apologies for coming across ungrateful.

I will speak to the homeowners tomorrow and see if they can contact the original builder and failing that I'll let them know there will be an extra cost for routing to a new outlet in gable end.

 

[John D v2.0]

No problem, hope it goes well!