Considerations for a small bathroom.

[Chris de Groot]

Hello all, I'm hoping you can guide me as I plan for a bathroom addition.

I am in Ontario, so OBC applies. The plan is to add a ground floor small toilet (toilet & sink, no shower or bath). The home is built around 1900.

The bathroom will need to be small, but still usable. It is going to take up part of an existing room that has one exterior wall.

Lucky enough the vertical stack is within 5' of the new toilets location and the stack has already had a ABS junction added to support a kitchen drain in the exact right location for the toilets drain. Hot and cold water and a dedicated vent line are also in easy reach.

Here are my questions or things I would appreciate some feedback on.
1. What is the recommended size for a small bathroom which is basically a narrow long room, toilet at one end, door opening inwards on the other short wall and on the long wall is a sink. I understand OBC requires 200mm on either side of the toilet and 600mm free in front. What about the room in front of a sink etc? Any plans for similar projects you can share. I'm leaning to a inner width of 3', but have not settled on a length, but basically the length of a toilet, sink, door and required setbacks.

2. Venting the sink is going to a lot harder then the toilet, because it is further from the stack that has a separate ABS vent. Is there a problem using an Air Admittance Valve for this small sink. The other option is to open up a lot of walls, some with tiling etcs.

3. The room would not have a window. I believe OBC requires I add an extractor in that case. Any pointers as to what is required there? I assume I connect it up with the light, or do I have to do something else?

4. The house has forced air heating/cooling. Do I need to have both a return as well as an out register in this room. I assume just the out register, but would like confirmation. where should it be located?

5. The old vertical stack (case iron) services bathrooms upstairs. What do I have to do for venting the new toilet? The distance from the stack to the toilet will be under 5'. There is a ABS vent close by that services a kitchen sink drain. Can I use that vent if needed, if so where does it need to join the toilet drain?

What other non obvious things come up?

Thanks for your feedback on this.

Kind Regards C.

 

[hj]

The distance from the stack to the toilet is completely IMMATERIAL. The design of the piping is what makes it material. WE cannot design a bathroom without knowing WHERE the existing piping is and where we can connect venting. Bathrooms do NOT have "return" air vents. The fan is operated along with the light. BUT, if you have to ask these questions, you are in over your head and need to consult with a professional.

 

[Sponsor]

 

[Terry]

I would tie the toilet vent to the kitchen sink vent.
In most places they like 2.0" for a toilet vent, but in Canada, they get by with 1.5"
The lav can use an AAV for the vent, since you do have an atmospheric through the roof already.

There is no need for return air in the bathroom, but you will need space under the door for air flow. I have seen bathrooms that were starved for air when the fan was on. Though, with a heat register, that may offset some of that need.

Any venting ties in above flood level of the plumbing fixtures.

 

[Chris de Groot]

That is very helpful, thanks Terry.