Output of extractor fan....

[rlc]

Hello,

Is it normal/acceptable pratice to vent an extractor fan into the roof space? In some cases it's difficult to get the flexible ducting into a sofit grille so locating to ducting as close to the sofit as possible - would be acceptable?

Cheers ~rlc

 

[securespark]

First of all, you need an extractor suitable for ceiling mounting.

Then, if venting vertically through a roof tile, you need to consider fitting a condensation trap.

You should not vent into the roof space itself.

 

[rlc]

Thanks securespark - I didn't think it was right when I saw the other day on a job that someone had fitted a shower fan + light kit in a shower room with the ducting pushed to the corner of the roof - I think the problem was that they could not get right to the soffit as the ceiling of the shower room came into the roof space and didn't implement a proper solution. I was just working as a cable puller as I am trying to learn the practical skills you can't buy so question most things I see

Just had a look at a condensation trap: http://www.tlc-direct.co.uk/Products/BGCT.html

As these are not suitable for flexible and I right thinking typically you go as follows:

flexible output from fan -> combination or horizontal / veritcal ridgid depending on run -> condensation trap fitted in vertical position-> ridgid and out through grille......would you then connect some hose to the 20mm pipe to run off the condensation to the outside?

Cheers ~rlc

 

[Glengyle]

Can anyone answer rlc's question above -

"As these are not suitable for flexible and I right thinking typically you go as follows:
flexible output from fan -> combination or horizontal / veritcal ridgid depending on run -> condensation trap fitted in vertical position-> ridgid and out through grille......would you then connect some hose to the 20mm pipe to run off the condensation to the outside?
Cheers ~rlc"

I am thinking about fitting a fan in my un-heated loft space and I'm fine with the condensation trap, drainage and vertical rigid ducting above the trap. But is there likely to be any condensation forming between the fan and the trap, causing a problem with the fan? And what's the actual ducting set-up between the fan and the trap?

Glengyle

 

[comms]

I fit flexi from fan to a pipe/flexi ducting connector, then short length of rigid pipe to trap, second short length of rigid pipe to second pipe/flexi ducting connector, continuing the run in flexi to the vent either in the soffit or through a gable end.

If going through a tile vent I use rigid pipe to a 2' height elbow through 90 degrees fit trap, through 90 degrees again & continue in rigid pipe up to tile vent (not forgetting to support the whole affair with some 2"x2" strategically nailed to trusses).

The trap drain off's I tend to connect into the tank overflow pipe somewhere along it's run or run out through the soffit/gable end.

http://www.tlc-direct.co.uk/Products/FD414C.html
http://www.tlc-direct.co.uk/Products/BGCT.html

 

[Glengyle]

Thanks comms,

I plan to go through a tile vent with the pipe and to drain the trap through the soffit.

I've just been up the loft and done some measurements. From the loft floor to the underside of the roof is around 2' 6" at the position I plan to exit the bathroom ceiling. The joists are 6" high. Should I mount the fan on a board on top of the joists with flexi duct between the bathroom ceiling and fan?

 

[comms]

If you are using an in line fan then yes.