I'm planning to install bathroom facilities in a small cabin with a plywood floor. The total bath area will be approx. 5' x 8'. Can you tell me if there is a proper order which to hook up the drain lines to the sewer pipe. ( I.E.vent pipe, tub, sink, toilet in that order)

Does one or the other have to be closest to the sewser pipe or does it matter?

Also, is there a good diagram I can view to best lay this out?

Thanks,

Gary

You don't need a diagram. The rough for a bathroom is simple. Most bathroom groups are roughed in like this.
Toilet connects to sewer main or the stack vent. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes.to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim.
Good luck, Tom

For a 5' x 8' bathroom I would run 3" pvc pipe directly to the toilet (end pipe run on toilet). I would add a dandy clean out just before the elbow going up to the toilet (just in case main line clogs). Then I would add a 3" x 2" wye just behind the dandy clean out...roll this above center line as it will act as a wet vent for the toilet AND act as a vent for the lavatory (all this should occur within 3-4 feet of the toilet elbow). It will be vital to run this 2" up to the attic/roof line and then tie that into your three inch PVC vent stack just before exiting the roof. This same two inch line will have a stub out (a 2 x 1.5" t fitting) at say 18 inches off finish floor for the lavatory. Then behind that 3 x 2 wye I would install another 3 x 2 wye...add a 2" dandy cleanout... reduce to 1.5" PVC pipe...then take an 1.5" t fitting off the drain line as your tub vent and continue run into the trap area of the tub and hook up a p-trap with a desanco fitting to the tub waste and overflow assembly of the tub.

If you have a three inch stack sticking out the roof already then you would simply tie your vents together in attic and then cut the one pipe into the vent stack. If you do not have a 3 inch vet stack through roof you will need to add one all the way from the bathroom up through the house and out the roof. This would be done by cutting a 3" wye into the main run before the bathroom fittings and running that pipe up and through the roof.

That is just an overview of one way to do this job. With this information and a good plumbing how to book (see home depot or LOWES) you should be able to do it.

I have assummed a lot here.. such as you only have 1 floor... such as you will not want to connect vents on same floor because a cottage and will probably just be easier to go straight up with vents then to start connecting them together about 4 feet off the floor.. although that could be OK as well.

If my answer helped please RATE THE ANSWER by clicking on button below.

Sorry... I do not have a picture... maybe someone else on site will.