bathroom fan question about ducting

[vw754]

hi,(hope ive posted in right place)

Ive nearly fitted a fan in the bathroom,drilled the holes ready for mounting,there was a plastic vent on the wall inside which ive took off,made a few adjustments.

The fan (150mm 6") fits in nicely ,im leaving the original air brick outside so no need mess with that.......do i need to put on a ducting on the end of the fan?.......from where the fan is to the brick is 8 inch long....i was told to put a ducting on and that will do.

If the fan is 150mm (6 inch) do i get a ducting a bit bigger to use or do the 6" ducting stretch over? also any clips/reducers?

OR C an i use solid plastic type ducting??????

 

[stem]

Flexible duct will fit over the spigot on the fan, it can be secured onto the spigot with duct tape or a jubilee clip. Being flexible it has the advantage of being able to accommodate holes that are not completely circular. The duct should slope downwards slightly towards the outside to prevent any condensation dripping back into the fan. Solid duct is acceptable also and can be sealed in place in the wall. With solid duct, the fan and grilles have a tight fit and can simply be pushed into place.

You will also need a proper outlet that can be secured to the other end of the duct to make a tight seal and stop moist air escaping into the structure of the wall. Just butting duct up to an airbrick will not achieve this.

Example of flexible duct
Example of wall outlet grille

You may also like to consider using an outlet grille with back draught shutters if there aren't any built into the fan. Otherwise you will have a draughty bathroom when it's windy.

 

[vw754]

Thanks stem.......will the 6 inch duct be ok for the 6 inch fan....i.e will it stretch slightly to fit over the fan? or do i need to buy 8 inch? im novice to the job mate,thanks in advance.

 

[stem]

It's designed to fit over the fan spigot, it will be tight, but it is deliberately that way to prevent air escaping.

 

[stem]

It's designed to fit over the fan spigot, it will be tight, but it is deliberately that way to prevent air escaping.