Connecting Extractor fan and Tumble Dryer Vents

[OhPinchy]

I have just added a downstairs toilet under the stairway in my house. My plan is to run the vent from an extractor fan in the toilet through the adjoining utility and out thru a new 4inch hole in the back of the house.

There will also be a vented tumble dryer and gas burner in the utility room. The gas burner will have its own 4 inch waste vent. I don't want to have 3 4 inch wastes going thru the wall as it may weaken it so I want to join the vent from the tumble dryer to the vent from the extractor fan and run them out the wall as one. Does anyone have any experience of doing something like this?

 

[PMU]

You can join the outlet from the vented tumble drier to that from the WC, but you will need an additional extractor fan on the vented tumble drier, otherwise the water vapour will flow back into the under stairs WC.

 

[OhPinchy]

Ok, thanks.

Would it be better to just go with a condensing tumble dryer then? I think I read somewhere about someone having a tumble dryer sitting above the washing machine (as I will) and they were able to have the condenser automatically drain itself into the washing machine below - has anyone done this?