Extractor in clockroom under the stairs - no external walls

[Pallatrax]

Hello gents,

I had a meeting with my building inspector yesterday in the hope I'd achieve sign-off on my self-build extension and knock-through, but I have a couple of things to do to please him.

I wrongly thought I could get away with not having an extractor in our under stairs cloakroom (split level, so more room than you think): there are no external walls (typical victorian semi layout, so stairs on party wall), so the ducting run would be unattractive, and quite long.

I have looked at a few possible routes, but one, which I'd prefer to use would mean ducting of approx 4.5m with two 90' bends.

As this extractor is just there to remove odours, should I/will he be concerned too much about the fans efficiency - as long as it is plumbed in and does an 'ok' job - if not a perfectly efficient one?

I should of lent on him for more information, but he left before I really had time to think about it, and he is now already out for the day, and it is all I can think about!

What are you thoughts?

Cheers
Tom

 

[Pallatrax]

I think I have no choice other than to put one similar to this in the loft space and head that way - there just isn't enough room to house one in the ceiling of the cloakroom.

http://www.screwfix.com/p/manrose-mf100-w-100mm-mixed-flow-fan/26867

Tom

 

[Pallatrax]

Question, as this room wont produce any significant moisture, being that is has just a toilet and basin, can the ducting just go into the unconverted pitched roof space, or will I need to fit a vent tile etc?

Ta

 

[OwainDIYer]

You should extract to the outside. although the WC won't be steamy the warm air from the house will still be moister than that in the loft.

Can you go under the cloakroom floor to the front or back of the house?

 

[Pallatrax]

Hi, and thanks for your reply.

I could've done just that had I planned the job a little better, but the idea of utilising this space came part way through the build.

Loft space I think it is. To be honest that inline fan is a lot better value than I thought one of its type would be...

Cheers
Tom

 

[oldbutnotdead]

Very unwise to vent into the loft. Your route with bends in- not ideal but as long as it achieves the required ventilation (in litres/second) and it fits the layout, do it. Best to get hold of the BCO with your alternate schemes and see which one he prefers- he might get quite sniffy at venting into the loft if its a modern draught-free structure (less of a problem if it is an old cold roof with wads of ventilation)

 

[Pallatrax]

It's old alright, covered in thick bitumen felt and clay double romans.

My suggested route is about the shortest to be fair - there just isn't an exterior wall nearby.