Venting an extractor hood through floor

[trevorbayliss]

Not sure which section to post this question in, but here goes.

I have taken up the bedroom floor to rejig the bath/bedroom around and have discovered the extractor hood in the kitchen is venting up the chimney, but now goes into the floor void in the bedroom as the chimney breast was removed yrs ago.

I can luckily attach some venting pipe to the hood and run it next to a joist and then out through the gable wall. This distance covered will be about 5-6m.

Does anyone know what i need to use? And do i need to fall the pipe downwards in case moisture collects ?

Any info appreciated.

 

[theprinceofdarkness]

yes a fall on the pipe will collect the condensation and allow it to drip outside (!). If you have a chip pan fire you do not want to set the bedroom under floor alight, so I would a, use a metal pipe and b, surround it with an additional layer of plasterboard. With a distance of 5m+, I feel that unless you use a 6" diam pipe or a VERY powerful fan, the air flow will be substantially reduced.
Frank

 

[trevorbayliss]

Thanks for info. Yes the flow will be reduced, but i am trying to make the best of a bad job. I dont really want to get a new fan in. I just think if i do provide some piping then it has to be better than the current situation where the fan dumps all the moisture under the floor.