Drain Layout plan, are reducers ok?

[bhil923]

I am trying to complete my bathroom and wanted to make sure that the drains/vent are setup correctly. I am not a plumber but I do understand some of the basics and am a descent problem solver, but fluid dynamics is definitely not in my wheelhouse.

Currently all of the drains are on the top side of the image and then "T" into the toilet drain pipe and only the pipe from the toilet is going through the joists. Also the sink is not in the wall currently but that is my new plan.

My main concern is the reductions in pipe diameters. My second concern is then going through the double joists.

Here is the basic layout, distances are not accurate but the order and general location are correct. The shower, vent and toilet are already in those locations and those sizes.

This is in a cabin and the pipes are fully accessible in the basement.

Thanks for the help!

 

[Jeff H Young]

heres a few pointers all those tees must be fittings called wyes or combination y 1/8th bends or sometimes called t wyes but regular tees and santees dont work. Id use a 3 inch combi at the toilet connection with a 3x2 bushing then upstream at the 2x2x1 1/2 combi id have on its back with the vent pointed verticle the vent musent be horizontal below trhe floor like that

 

[Sponsor]

 

[bhil923]

Thank you i'll go with those combi wyes for the vent, toilet, and might as well the sink too. A quick look I could not find a combi wye that goes from 4 to 3 and 3 so would it be safe to run another reducing bushing from 4>3 at the toiled drain pipe and then doing a 3x3x3 combi wye, do you think?
I'll likely head into town tomorrow to see if I can find them local else i'll have to go to one of the bigger stores a little further, or order online to get what I need.
Thank you again, I didnt even think of that, but I remember seeing those wyes in the past and this helped me to not make a poor decision.

 

[wwhitney]

A quick look I could not find a combi wye that goes from 4 to 3 and 3 so would it be safe to run another reducing bushing from 4>3 at the toiled drain pipe and then doing a 3x3x3 combi wye, do you think?

If you want a 4" closet flange, the only way you are allowed to reduce to a 3" toilet fixture drain is by using a 3" x 4" reducing closet bend. So do that, or use a 3" closet flange. There is never any other allowance to reduce drain size along the direction of flow.

Cheers, Wayne

 

[Jeff H Young]

I think op is mixed up you cant use a 4 inch fitting other than a reducing 90 as wayne mentions.
Op are you with us with proper fittings that have sweep ? not the same as water pipe fittings these are drainage