ᐅ Bathroom renovation, new wastewater pipes installed on the opposite side of the room

Hello, we are buying a house and want to remodel the bathroom, which includes creating an opening to the adjacent room.

In the old bathroom, the shower and toilet will remain in their current positions. The washbasin will be removed, so the original drain will still be used.

Since the other side of the room is too far to extend a pipe there, we thought we could run a drain pipe from the kitchen underneath the new room and then upwards.

I believe there is no ventilation for the wastewater pipe on this side of the building. See the picture (original pipes in red – new ones in green).

If we extend the pipes upwards and install a bathtub plus a double washbasin, we will probably need ventilation. Can this be done with a valve inside the room? Or is it even necessary here?

Thanks in advance. 🙂

No, you don’t need a separate vent anymore.
20 to 30 years ago, a dedicated vent was often installed through the shower or similar areas.

Today, modern fittings come with built-in venting. Just ask at a specialist retailer for more information...

I think you are talking past each other. The original poster means wastewater ventilation, and you mean fresh water ventilation.

@TE: yes, you might need one. From the picture, the kitchen is located close to the main stack ventilation (depending on the pipe diameter to the kitchen and the length).

Since a main vent is shown in your plan, a ventilation valve will most likely be sufficient for the branch line.

Ah yes, that can happen :P
That’s the downside of written words; they are often misunderstood or not read carefully.