A shower drain is 1 1/2 or 2 inch and a toilet needs to be either 3 or 4 inch.
You need at least a 3 in. pipe -- shower is 2 in. pipe
If you reduce the soil connection to 2" and install a trap
Take a shower, use the toilet
Are the shower and toilet blocked in your bathroom?
No, flushing the toilet does not affect the temperature of the shower water.
A down line clog would cause this. The shower drain is lower than any other drain in the bathroom so it is the first to tell you of a clog in the line. Time to Roto Rooter! Y-THINK-Y The toilet and shower must have the same drain. There is a blockage somewhere after the toilet and shower drains meet. The backup takes the easiest route back which must be the shower drain. Try snaking out both drains. Start with the toilet. To do the best job, remove the toilet and start from floor level.
It might mean that there is air in the line. Maybe install a water hammer.
This can be a complicated job as the toilet drain ranges from 3" -4" and a variety of materials from Plastic to cast iron to galvanized. Then there is the venting to consider and NO a shower drain CANNOT be used for a toilet discharge as the shower drain is normally 2" diameter
Flushing the toilet can affect the water temperature in the shower because both the toilet and the shower are connected to the same water supply system. When the toilet is flushed, it temporarily reduces the amount of water available for the shower, causing a drop in water pressure and potentially affecting the temperature of the water coming out of the shower.
Toilet bubbles appear when you shower because the water pressure from the shower can create air bubbles in the plumbing system, causing air to be pushed through the pipes and into the toilet bowl.
what is the cost to install a fiberglass shower
This indicates that it has a toilet, sink and a shower but no bathtub. A 1.50 indicates that it has a toilet, sink but no shower or bathtub.