Noisy En Suite Extractor Fans!

[nickfrench999]

Wasn't sure where to post this so hopefully this is in the right place. Posting on here in the hope that I can get a good night sleep this winter - please help! We have an en suite and when the wind is in the right direction the extractor bangs - or rather 'clonks' so much that it keeps you awake all night. There are 2 sounds I can hear when it;s windy - the rattle of the exterior slatted vent on the outside of the house and then this more bassy, clonky noise. It's coming from up inside the extractor pipe. I've been up in the loft and can see two white plastic extractor tubes and then a solid grey one - which I think is the one coming up from the en-suite. The other two are from the main bathroom and the downstairs toilet. I'm guessing inside the grey plastic one one is the same white plastic tubing that I can see if I peer into the extractor grill in the ceiling. So what is the clonking sound? it almost sounds like a disc pivoting along it's axis which is rotating when the wind blows into it? It seems to be a lot better when I pull the light switch and the extractor kicks in?

Does anyone have any ideas as to how I can stop this darn noise??!

 

[Gemma Bush]

Buy an inline flap, fit hi in the loft near the fan. i shud stop the wind and only open when fan blows. not electrical so a DIYers job