Air vent into soil stack?

[DodgyDIY]

Hi

I've got a 100mm in-line fan to extract air from the bathroom and was hoping to use what I see as a shortcut for the outlet.
There is a soil stack in the same loft space the I thought maybe I could branch into. That would save me drilling through walls OR using a vent cowl & insulated condense trap into the soil pipe.

Is that going against regs?

The only risk I can think of is the backflow of foul air into the bathroom but a backdraught shutter should cure that.

It just seems too easy and I am sure there must be a reason why!

TIA

 

[ShaunCorbs]

No you can't tee into the stack vent for a fan sorry

 

[DodgyDIY]

Thanks for the quick reply mate. Knew it was too good to be true

Cowl it is!

 

[Chalked]

Even with a back flow flap. The drain gasses and smells would back up

 

[king of pipes]

No no bud it has to be separate connection vented to fresh air