A few questions during replumbing an old house

[mikewass]

Hi all! This will be my first post here, so I'm hoping for the best.

I am in the process of replumbing an old house that was built in the 1920s. There were a lot of "hack jobs" done over the years in order to do some bathroom and kitchen remodeling. So, I'm hoping to correct those problems while also modernizing the plumbing systems that are/were once accepted with ABS/PVC and PEX materials.

Here are my questions so far:

1. Is it acceptable to connect multiple vent stacks in an attic to a single roof vent regardless of critical distance? I have been researching this constantly and I have not been able to find a concrete yes/no answer.

2. Is it acceptable to use a 1.5" drain line for a tub/shower and a single lav with proper traps in place? I'm aware that it depends on the code in the area, but it also seems to be something that has changed recently? I'm unclear.

3. Are drum traps obsolete and/or unacceptable when used for tub waste? I'm aware that "S" traps are not acceptable, and "P" traps are preferred. Is there a rule of thumb for "P" trap versus drum trap?

I should mention that I've provided plans and received a permit from the local plumbing authority. I am also planning to hire a certified master plumber to provide his professional opinion before final inspection, but unfortunately my financial situation is forcing me to DIY most of the work.

Thanks in advance.

Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

 

[Cacher_Chick]

Your vents must be sized appropriately for the number of DFU's of the fixture(s).

A lav can be 1.5 and a tub can be 1.5, but you cannot combine both into a single 1.5. Unless it were a short run, I would pipe 1.5 traps into 2" drains.

Drum traps do not meet current code, but are grandfathered if you are not changing the plumbing.

A P-trap is the only accepted trap, and it must be vented.

 

[Sponsor]

 

[Jadnashua]

Don't mix abs and pvc...pick one type and stick with it. While there are some transition cements, they may not be accepted everywhere and are best avoided. If you choose pex, keep in mind that the wall thickness is greater, so depending on what you are plumbing, you might need to go to a larger supply line to maintain your desired flow and pressure.

 

[hj]

quote; I am also planning to hire a certified master plumber to provide his professional opinion before final inspection

"before final inspection" is the wrong time to ask him. You need his input, if he will give it to you, BEFORE you install the piping. If you wait until the inspection, any revisions could be very expensive to do. I have had customers do it, and my "repair" was to take a SawZall and cut it all out and start over, doing it myself. And they were working from a drawing given to them by the city building department, but they did it the way they "thought" it was drawn, not the way it was.

 

[mikewass]

"before final inspection" is the wrong time to ask him. You need his input, if he will give it to you, BEFORE you install the piping. If you wait until the inspection, any revisions could be very expensive to do. I have had customers do it, and my "repair" was to take a SawZall and cut it all out and start over, doing it myself. And they were working from a drawing given to them by the city building department, but they did it the way they "thought" it was drawn, not the way it was.

Thanks for your recommendation. I have met with a plumber previously who gave me his opinions and I have been working with my father in law who has a few years of experience in the trades. Granted, neither of us are plumbers. But, I think that the information that I have received along with plenty of research and both of us working on it will result in something workable. I realize that it is a bit risky, but I don't have much choice at this point.

Thankfully, the situation dictates that there are not a lot of alternatives. I'm well aware that plumbing code has limits and we're working within them. That said, I'm expecting that if any errors are made they are minimal.