Reducing ducting size

[Jamespf1]

Hello,

installing a downstairs closet bathroom in a terraced house and need to put a extractor fan in the bathroom.

Only solution I can do is either run ducting along a bedroom wall… not the best
Or
Run ducting in studwall however I would have to reduce down to 50mm. What sort of problems might occur?
There won’t be shower just a basin and toilet in the WC. And don’t mind replacing the fan every couple of years if it was to put strain on the fan if i was to reduce the ducting.

Thanks

 

[JohnW2]

Or .... Run ducting in studwall however I would have to reduce down to 50mm. What sort of problems might occur?

Inadequate air flow - although, if you use a relatively powerful fan, you might possible get an adequate flow through a 50mm duct.

Kind Regards, John

 

[Sureitsoff?]

Would the op really need a powerful fan as it's just a closet. Surely any airflow if slow is better than nothing, so small ducting but perhaps a long run time would suffice?. My downstairs closet has a fan that goes on and off with the light and if it's a bit. " give it 5 minutes!" We just leave the light on.

 

[RandomGrinch]

Can you use rectangular ducting? - although the standard size is 110 x 54mm

110mm x 54mm Flat PVC Ducting Clips - Ventilation

 

[JohnW2]

Would the op really need a powerful fan as it's just a closet.

I did say "relatively powerful", and a standard one of decent make may well suffice for the OP's needs. Some of the cheapo ones tend to be anything but "relatively powerful"!

Surely any airflow if slow is better than nothing,

That goes without saying.

As RandomGrinch has said, the usual approach to the OP's issue would be to use rectangular ducting, and I'd be very surprised if that would not fit in a normal stud wall (provided it could be run vertically within the wall).

Kind Regards, John

 

[EFLImpudence]

Why bother (with a fan)? How bad would it be without one?

 

[RandomGrinch]

Why bother (with a fan)?

It depends if BC are involved...

 

[EFLImpudence]

ADF is like ADP - merely guidance.

Part F does not say fans are compulsory.

 

[RandomGrinch]

ADF is like ADP - merely guidance.

Part F does not say fans are compulsory.

Does everything have to be a fight!

Building control should be involved with this project, as it requires a new foul drain connection. They will very likely be interested in other aspects of the work.

Yes, fans are not compulsory under part F, but for the sake of pragmatism and gaining my completion certificate, I would be looking to follow the BC guidance.

 

[EFLImpudence]

Does everything have to be a fight!

No. Who is fighting?

Building control should be involved with this project, as it requires a new foul drain connection. They will very likely be interested in other aspects of the work.
Yes, fans are not compulsory under part F, but for the sake of pragmatism and gaining my completion certificate, I would be looking to follow the BC guidance.

Ok.

I would prefer the building inspector to be correct and not cause a fight.

 

[JohnW2]

ADF is like ADP - merely guidance. Part F does not say fans are compulsory.

All true - but, as we know, just as the guidelines of Approved Documents are not compulsory/mandatory, nor, it seems, is it compulsory/mandatory for BCO's to restrict their 'requirements to what is actually required by the Building Regs (Part F in this case) - and it seems that many of them probably use the Approved Docs as a guide to what they will personally 'require'.

When a BCO 'demands' something which is not actually required by the regs, there is obviously potentially scope for argument, but many probably feel uninclined to get involved in all the hassle (and they may not 'win').

If one wants a fairly quite life, then a degree of pragmatism may be required. If a BCO demands a fan, then he/she may well be satisfied by seeing some sort of fan, with any sort/size of ducting (if any!), even if the fan is removed immediately after the Completion Cert is issued

Kind Regards, John

 

[EFLImpudence]

Of course, we should not expect those in charge to know what they are doing and just put up with it when they don't for a quiet life.

Just do as you are told.

 

[JohnW2]

Of course, we should not expect those in charge to know what they are doing and just put up with it when they don't for a quiet life. Just do as you are told.

We definitely ought to be able to have that 'expectation' but, as we know, that is not necessarily 'how it is' - so I'm afraid that, in practice, considerations of 'a quiet life' inevitably come into the equation.

Kind Regards, John