Yes, there are guidelines, and there are building codes.

Do you know how to use google?

Do you have a local showroom, where you can stand in a 36” and a 30”.

If not, out some tape on a floor.

Is there a reason why you are not working with your designer?

I question the designer advice about size of shower. I can use google but i am not sure if there is a showroom I can visit. Thank you for the advise,

I can not help you with your designer‘s advice.

Building code maybe 30x30, recommendations are 36x36.

Can you put some tape on the floor, maybe some cardboard for walls.

Larger people like larger showers. What is your age and weight?

Is this a designer or a sales person?

google will provide the tables,

If you are converting the tub to a shower why is there a size question. I replaced my tub shower combination with a walk in shower that followed the footprint of the tub. The toilet remained where it was and the shower is a very comfortable size even with the built in bench I had installed.

Designer would I believe get a commission. Thank you, you have answered my questions.

Helen,

I read the OP would have to move a toilet.

We replaced a tub/shower combo with just a shower, and it was 30 x 60 because that’s what the tub was. No need to move toilet. If you post a drawing of your space people on here can be more specific which their advice.

I am questioning why the toilet needs to be moved - just seeking clarification. If you are replacing a tub with a shower, it is generally large enough just following the footprint of the original shower.

Showering in a tub/shower set up is a completely different showering experience than showering in a stall shower because you have the length of the shower which makes it comfortable. Even a 36" x 36" shower is very confining in terms of hitting your arms if you raise them precipitously to wash your hair or bending down to attend to feet or shave or whatever on lower portions of body is confining.

So when you replace the tub/shower with just a shower it feels more expansive. Also there is generally more room for feet in the shower because many tubs have a curved bottom so the actual flat area is less than it is in a walk in shower with a floor that is gently sloped towards the drain.

AJCN. Posting picture. (not exactly to scale).

Proposal. Replace tub with 36 inch shower, move toilet to right, reorient vanity sink to wall on right. Way over my budget. Thank you for ideas.

A toilet requires 30" space .i.e. 15" minimum from its center (drain). It seems that you have a lot of space to widen your shower without moving the toilet. Placing the vanity along the angle wall is worth it imo.

I redid layout with bottom wall 6'3"" and you could still do a longer vanity on that wall. Use the a wall hung toilet or a round bowl toilet to keep the toilet from taking up too much room.

If you tub is in good shape and space is at a premium, you could keep the tub and add a curved shower curtain rod to give the shower more elbow room.

I think the issue is that the tub is 29"x54" and the designer is saying the shower width needs to be 36"x54" which means move the toilet over.

I think a 29"x54" shower would be fine. You don't have to widen it, because you can turn your body sideways to get elbow space as needed.

Kohler makes its Model K-9165 60" x 32" shower base with a left offset drain and Model K-9166 60" x 32" shower base with a right offset drain. Per Kohler these shower bases and their offset drains are specifically designed for easy replacement of a 60" x 30" bathtub. Why someone would claim a shower must have a minimum 36" dimension is unclear.

I agree, you don't need to widen it if you don't want to. Your shower will have more floor space than the current tub you have but if you like to widen it, I believe you could go up to 38". According to your drawing you have 9" followed by a full 30" you have allocated for the toilet (that is if each each vertical line are at 6" apart).

How much space between the shower side and the toilet tank is normal? There is currently 9 inches.....I am thinking that 7 inches would be adequate.

If your measurements are from the shower to the left side of the tank, I believe 7" from each side of the tank would give you about 32" space for the toilet. That calculation is based on the size of the tank of my toilet which is 17" wide.

"How much space between the shower side and the toilet tank is normal?"

Don't measure from the tank. Measure from the centerline of the toilet to the adjacent surfaces. It should be at least 15" on each side.

Is the plumbing of your tub on the same wall as the toilet?

Yes

Your designer is suggesting what's hip, what's new, what some would consider the optimum. As stated by a few above, using the same foot pint the tub takes up now means you do not have to move the toilet, it will function with plenty of room (do you shower there now? ) and will be much cheaper. Find a new designer.

It may be apples and oranges to some, but showers in RVs are often 24" wide.

JM$.02W

I changed tub to shower in tub footprint and was worried about width but my 6’1” son says it’s fine!

Thank you one of the reasons we are considering changing to a shower is our 6'7" grandson.

I am 5'2" and I have to keep the shower door opened in a 30"x30" shower because I can't bend to wash my feet. Your grandson would definitively not fit in a RV shower.

A 30"x54" is working because of its length.

You can get shower pans from Swanstone that are only 30” wide. A 30” wide shower is fine for most, as long as the length of the shower is at least 48”. A length of 36” would feel tight to many. But you have 54”, which should be fine.

Now, be sure that whatever method you use for the shower uses the proper materials, including waterproofing. No drywall. Cement board is not waterproof and needs either plastic sheeting behind it, or waterproofing on top. There are lots of waterproofing methods available, but make sure that whoever makes your shower uses manufacturer’s instructions for installation. Oh, and tile and grout is not waterproof, which is why you need waterproofing under it. If you go fiberglass or acrylic or solid surface like Swanstone, make sure you follow the installation specifications of the manufacturer!