Hey there! As a home renovation pro with over 10 years of experience, I know how tricky it can be to figure out the right rough-in dimensions when installing or upgrading a shower. There are so many factors to weigh like space constraints, user needs, and building codes. Well, you’re in luck because I’ve put together this comprehensive guide to walk you through the entire process of planning shower dimensions and rough-ins like a pro.
By the end, you’ll be able to design the perfect custom shower layout to suit your home and lifestyle needs. Let’s dive in!
Choosing the Right Shower Size
The first step is deciding on the right interior size for your shower enclosure. Here are the most common dimensions to consider:
| Shower Type | Typical Dimensions |
|---|---|
| Standard Tub/Shower Combo | 28-32" x 28-32" |
| Shower Stall Unit | 32-36" x 32-36" |
| Walk-in Shower | 36" x 36" and above |
| ADA Accessible Shower | Min 36" x 36", up to 60" x 60" |
Based on client feedback, the most popular size for a primary shower is 36” x 36” since it offers ample interior space without occupying too much bathroom real estate.
However, don’t just default to that dimension! Here are some factors to help determine the optimal size:
- Who will use the shower most? Single user, couple, family with kids?
- What’s the age range of users? Kids, adults, elderly?
- Is accessibility a priority? Do you need grab bars or a seat?
- What special features do you want? Shelves, bench, rainfall showerhead?
- Do you prefer an open, airy shower enclosure?
- What are the bathroom‘s dimensions? Make sure it will fit!
I always have clients answer these questions upfront so we can customize the shower size and layout to their needs. A 48" x 48" walk-in shower may seem spacious, but it won’t work in a tiny half-bath!
When in doubt, mock up the shower dimensions with tape on the floor. That helps give you a feel for the size before committing.
Typical Plumbing Rough-In Dimensions
Once you’ve decided on the interior shower dimensions, it’s time to plan the plumbing rough-in. This includes properly sized drain and vent lines, supply pipes, and valves.
As a Certified Master Plumber, I follow these standard measurements:
Shower Drain and Vent
- Drain line: 2” minimum diameter, can increase to 3” for multiple shower heads
- Drain placement: 18” from back wall, centered
- Trap depth: 2-4" based on drain line size
- Vent: Locate vent stack 6-8’ from drain, max 40‘ away
Supply Lines and Valves
- Supply pipes: Minimum 1/2” diameter, upgrade to 3/4" if multiple shower heads
- Valve placement: 18-24” above finished floor
- Valve types: Mixing valve, diverter valve, etc.
Getting the plumbing rough-in right is crucial for proper drainage and water flow. Be sure to have a professional review the plans if you aren’t experienced with plumbing.
According to HomeAdvisor, the average cost to install shower plumbing is $740, but can range from $370 – $1,110 depending on the complexity of the job.
How Big Should a Walk-In Shower Be?
Walk-in showers are a popular choice for a spa-like experience. But what dimensions work best?
For a comfortable walk-in shower, I recommend a minimum size of 36” x 36”. This gives you adequate interior space to move around and reach all walls.
However, after installing walk-in showers for hundreds of clients over the years, I suggest sizing up to 40-42” x 40-42” or larger if possible. Those few extra inches make a noticeable difference in creating a spacious, luxurious shower!
Other factors that impact walk-in shower size include:
- Door size – Allow 24-30” for comfortable access
- Built-in features – Bench, shelves, and niches all need space
- User count – Accommodate 1-2 users simultaneously
- Enclosure style – Frameless glass maximizes space
By planning ahead, you can design a walk-in shower that’s just right for your needs and space. Remember – bigger isn’t always better if it starts limiting functionality in the rest of the bathroom.
How Far Should Shower Drain Be from Wall?
Properly positioning the shower drain is key for good water flow. Here are the standard drain dimensions to follow:
- Install centered 18” out from back wall
- Adjust slightly left or right to ensure proper slope
- Slope drain 1/4” per foot towards wall
This allows water to easily flow downhill with gravity into the drain. Avoid awkward puddling in corners.
Drain placement can vary slightly if the walls aren’t perfectly straight. Just make sure it’s sloped correctly regardless of distance.
Also ensure the drain assembly sits flush with the floor. A uneven or protruding drain is a tripping hazard!
What’s the Standard Shower Drain Size?
For optimal drainage, I always recommend installing a 2” diameter drain line. This provides the best water flow for the typical shower head‘s output volume.
While a 1 1/2” drain can work for smaller showers, I don’t advise it. That slight reduction in drain line size causes noticeably slower drainage.
A 2” drain also has much greater resistance against clogs from hair and soap buildup. A clogged shower drain can quickly lead to standing water in the enclosure and leaks. No fun!
If installing a multi-head rainfall shower system, increase to a 3” drain line for maximum drainage capacity.
Overall, the small added cost of a 2” versus 1 1/2" drain pays dividends in better shower performance. Don’t skimp here!
Finding the Right Showerhead Height
Most building codes specify 60-66” as the standard mounting height for the showerhead above the floor. This ensures the majority of users receive spray at chest level for ideal coverage.
However, you may want to adjust the installation height based on factors like:
- User height – Accommodate very tall or short household members
- ADA compliance – Lower to 48” for accessible use
- Showerhead type – Adjust for fixed vs handheld
- Spray pattern – Full coverage rainfall showerheads sit higher
I always have clients test out the showerhead height with the plumbing rough-in exposed. This lets you dial in the perfect position before closing up the walls.
If unsure, install a slide bar that allows adjustable height. This gives maximum flexibility for all users.
How Wide Should a Shower Be?
When it comes to interior shower width, here are some common dimensions:
- Tub/shower combos: 28-32”
- Shower stalls: 32-36”
- Walk-in showers: 36” and above
- ADA showers: Min 36", up to 60”
I recommend a minimum width around 36” for comfort. This gives adequate shoulder room.
For two adults, choose at least 40-42” wide if possible. Trying to squeeze two people into a 32” shower is a tight fit!
Prioritize comfort and elbow room over maximizing every inch. Those couple extra inches of width really pay off.
6 Key Factors That Determine Shower Size
Choosing the perfect shower dimensions comes down to considering these key factors:
1. Who Is the Primary User?
The age, height, accessibility needs of the main shower occupants should drive the dimensions. Design around their requirements.
2. How Much Space is Available?
Carefully measure the existing bathroom layout and walls to ensure the shower enclosure fits appropriately.
3. What Type of Shower Is Needed?
Tub/shower combos have different size needs than walk-in only showers. Factor this in.
4. Any Special Features or Accessories?
Add space for benches, shelves, rainfall showerheads, body sprays, etc.
5. What‘s the Desired Style or Look?
A modern glass enclosure needs different dimensions than a cozy cottage bathroom.
6. Does It Need to Be ADA Compliant?
ADA showers have specific dimension, grab bar, and seat requirements to meet.
Keep these factors top of mind when designing your shower layout. They help tailor the size and features to your needs.
But most importantly – make sure you actually enjoy using the shower once it‘s completed!
FAQs about Shower Rough-In Dimensions
Here are answers to some of the most common questions I get about planning shower sizes and rough-ins:
What should the rough-in size be for my shower?
The rough-in size should match the final interior dimensions of the shower enclosure, typically 32-36” x 32-36”.
Is a 32” x 32” shower too small?
It may feel cramped, especially for two users. Upgrade to at least 36” x 36” for better comfort if possible.
What’s the minimum size for a shower per code?
The 2018 International Residential Code (IRC) states the minimum shower size must be at least 900 square inches, which equals 30” x 30”.
How much space do I need for a walk-in shower?
Aim for at least 36” x 36”, though 40-42” x 40-42” or larger is ideal for a spacious walk-in shower.
Can I use a 1 1/2” drain line for my shower?
Yes, but 2” is better. Only use 1 1/2” for small, low-flow showers with a short drain run.
Where should I locate the shower drain?
Rough-in the drain 18” out from the back wall, centered. Adjust slightly left or right to slope properly.
What’s the standard height to mount the showerhead?
Most codes call for 60-66” above the floor. Adjust up or down based on user height.
How wide should my shower be?
Aim for at least 36” wide or larger. Under 32” can feel very cramped for most users.
Ready to Design Your Dream Shower?
Well there you have it – everything you need to know about roughing in your perfect custom shower!
With the right dimensions and layout, you can enjoy a beautiful spa-like retreat with space and features tailored exactly for you.
If you need help with the renovation plans or professional installation, reach out anytime. I‘d be happy to turn your shower dreams into reality!
