You can use an AAV for each of these. This prevents having to cut the roof.
The drain is plugged somewhat between the upstairs and downstairs. Need to snake the drains.
The drains for the shower, toilet and sink all connect to a common line. Assuming the toilet is not backing up, the problem indicates that there may be a partial blockage, enough so that some of the toilet flow is backing up through the shower drain line. You need plumbing repair. The shower leak you mention should only be in the shower, or else you have a broken drain line as well.
You need at least a 3 in. pipe -- shower is 2 in. pipe
Sure, honey, the drains for the shower and sink can definitely come before the toilet drain. As long as everything eventually connects to the main stack, you're good to go. Just make sure you follow local plumbing codes and use proper fittings – we don't want any leaks causing a stink!
If both your toilet and shower are clogged at the same time, you should try using a plunger to unclog them. If that doesn't work, you may need to call a professional plumber for assistance.
In some RVs, it need be only two feet by two feet, and you can straddle the toilet while the overhead shower showers you.
Yes. Toilet, shower, sink, or any other fixture that you might have needs to have a vent. Why? --->>> Toilet, shower or sinks are all independent fixtures where they all individually need air in order to flow properly. Any of these fixtures will not take air from the same vent you have at the basin.
You need either a new O ring in the shower or tap anew washer in the tap, or you should go to the toilet before showering.
Yes, you can fix a toilet and shower clogged at the same time by using a plunger or a drain snake to clear the blockage. If the clog is severe, you may need to call a professional plumber for assistance.
One drain outlet is sufficent provided the drain outlet to the sewer line or to the gully outside has the correct gradient fall.
Yes, humidity created by the shower can cause mold. they dont call it a fart fan for nothing. You mention a shower but say nothing about a toilet. I assume the "powder room" has a toilet. In most cases, a toilet exhaust fan is required by building code unless there is an operable window in the space. Check with your local building code officials but, in the mean time, assume it will be required.
we need storm drains because it helps the city not over flood