Extractor fan & loft condensation: two problems or one?

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Dear DIYNOT folks

A few years ago I bought a 1980's flat with a loft. The bathroom extractor fan was broken so I got a man round. The fan feeds into a vertical pipe that goes thru the loft and exits thru the roof. The man said the fan was broken due to rust from condensation coming down the pipe. He then said the cure was to replace a section of the piping with a long flexible hose: the condensation would settle in the hose and evaporate gradually. That cure was implemented[X] and I now have to empty the hose periodically.

Flash forward three years. I have developed condensation in my loft. And I'm beginning to think the hose and the condensation are connected, and that the man may have been in error. I have replaced the man with a more reliable handywoman and I have also gotten a reliable plumber. And now I need to work on a cure.

I have noted the contents of //www.diynot.com/forums/viewtopic.php?t=160032 . I have modified my behavior (less showers, no drying clothes in flat, switch heating off in rooms that are empty) and my handywoman is coming around in January to implement the "quick wins" (tighter loft trapdoor, cut loft insulation away from roof edges to free circulation, stop up holes in ceilings, etc). But I need to know what is the best cure to the fan problem.

So I'd be grateful if you kind people would tell me which of the following would work:

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  Option 1) Replace the flexible hose with a vertical pipe as before [1]
  Option 2) Replace the flexible hose with a vertical pipe but with a proper condensation trap,[2] with the overflow being directed to a bottle/canister will have to be periodically emptied.
  Option 3) Replace the flexible hose with a vertical pipe but with a proper condensation trap,[3] with the overflow being directed to the soil pipe (which runs thru the roof, loft, my flat, and the flat downstairs)
  Option 4) Replace the flexible hose with a vertical pipe but with a proper condensation trap,[4] with the overflow being directed to the soil pipe and many u-bends introduced to prevent smells backing up.
  Option 5) Replace the flexible hose with a vertical pipe but with a proper condensation trap,[6] with the overflow being directed to the outside via a horizontal pipe.

I presume option 5 would be the best, but my lease (my flat is leasehold) has a clause saying "no structural alterations nor structural additions" and I do not know if option 5 will violate that. So I have to investigate the other options.

Thank you for your time.

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[Burnerman]

Your extractor needs the shortest possible pipe run, and also needs to be timed to run longer after the showering is over.
Plastic pipes are warmer than steel - even consider lagging it to keep it as warm as possible.
Is there some sort of rain cap on the pipe that exits through the roof?
Ideally the fan ducting should exit through the wall or soffit of the building, but maybe thats not possible?
John

 

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It is not physically possible to exit the ducting via the walls to left and right, since the flat is sandwiched between two other flats.

It is not physically possible to exit the ducting via the walls to fore and aft, since the ducting is in the loft and there are no walls fore and aft.

It is possible to exit the ducting via the soffits, but my lease (the property is leasehold) has a "no structural alterations nor additions" without permission clause, and that may apply here. I can initiate the procedure necessary to get permission via my chartered surveyor and lawyer, but getting permission is lengthy and expensive, so I'd like to avoid doing anything that invokes that clause. Hence my questions about alternate methods (discharging the condensation into the soil pipe, or into a lagged bottle, etc: see pictures).

I take your point that it is better to have plastic piping instead of steel, and better to have lagged piping instead of unlagged piping, and better to have a longer timer (e.g. continue running ~5mins after light goes off) than a shorter one. It has plastic piping but the fan goes off immediately with the light and it is unlagged, so there is two quick wins.

Regarding your question about a pipe on the end of the cap: I believe it does have such a pipe cap, yes.