Finding the distance between a tub spout and a valve is easy. With reliable industry standards and detailed instructions, most manufacturers streamline the process.
You can use a standard measurement of six inches between the tub spout and the valve. For precision, every kit from a trusted manufacturer should have recommended distances.
How to Set Up the Tub Spout and Valve
I recommend checking the instructions. The directions should recommend standard distance ranges of 6 to 18 inches. Next, set the spout at least six inches above the top of the tub. These six inches give you room to get in with a tool if needed.
Establish the Spout Height
When installing a tub spout and valve, most people like to decide where to put the spout first. When you measure how high above the tub to put the spout both practicality and aesthetics apply.
Start by looking at the underside of your spout and seeing if there is a slot for Allen Key adjustments. Many manufacturers put a place for an Allen Key but not all.
Imagine the finished installation in the future, and you need to go use an Allen Key on the spout. If the spout is too close to the tub, you will find getting the key in and working difficult.
Most people, including myself, like to set the spout about six inches above the tub. Half a foot looks good, and getting in with an Allen Key later will not be too difficult.
The other factor to consider is how far the water falls into the tub and splashing. Most of the time, splashing will stay in the tub without an issue. I recommend keeping this factor in mind.
Some tubs are deep, and some are shallow. Having the spout about six inches above the top of the tub usually works.
Determine the Distance Between the Tub Spout and Valve
The first step is to refer to the manufacturer’s instructions which advises the distance. The kit you purchased should have the spout and everything you need to assemble the valve. You only have to supply the pipes and some tools.
The manufacturer designed a distance from the spout to the valve, usually about 6 to 11 inches. Sometimes the distance is 8 to 18 inches.
In the average home, you will find that most systems leave about 6 to 10 inches between the spout and valve.
The reason for the specific distance range is the water has to flow through the spout or up to the shower head. The manufacturer has determined how well their products perform. Sticking with the recommended distance range is a good idea.
Now you know how your bathtub external plumbing will look. You have the tub, the distance the spout is above the tub, and the distance the valve is above the spout.
The distance the shower head is above the valve can be wherever you will be able to shower comfortably. The distance between the tub spout and valve is the only one that has to fall within a specific range.
The materials you use to install the plumbing for a bathtub are fairly robust. You do not need extensive tools to work with the materials. Most of the parts screw together, so you can get pretty far with only Teflon tape and an adjustable wrench.
You should have either 2×4 or 2×6 supports to hold the faucet and valve lines in place. Your valve might have several threaded holes for connections. You need to mount the valve to the boards, so only use the holes at the back of the valve.
Use a pencil and ruler to draw guidelines on the board. You want the valve to be straight and in line with the center of the tub. When you are ready to screw the valve in, you will need a couple of wood or deck screws and an electric drill to make the job easier.
Screws stabilize the valve, so you avoid having the system sway around on Pex pipes.
Speaking of pipes, if you have to make adjustments to get them to fit in the valve, you will need a suitable cutting tool.
You should also have a set of Allen Keys and some different screwdrivers handy in case the kit has screws of different types for various purposes.
Not many problems can arise getting the measurements right between the tub spout and valve. You are more likely to have plumbing or construction-related issues.
Why does the distance between the tub spout and valve matter?
The main reason is because of back pressure. When you use the spout to run a bath, there are two reasons water might come out of the showerhead and the spout. The distance between the spout and valve might be wrong, so pressure builds and forces some water out of the shower (if there’s no water pressure in your shower, but plenty everywhere else, check out our guide here).
If you do not have a back pressure issue, but water comes out of the shower, the valve is probably leaking. The way you can tell what is going on is to look at the way the water comes out of the shower.
Consistent flow means the valve is letting water pass to the shower head. If the water slows to a trickle and begins to drip, there was probably some excess water in the pipe. The valve is probably working correctly.
Why can’t I attach the valve to the shower wall instead of the boards?
You could, but having free-standing plumbing on flexible Pex pipes is a sign of poor workmanship that invites plumbing issues. Sometimes when people have to remove a shower wall, they discover that the valve did not get secured into anything.
Take the time to go through the instructions with your kit and use the recommended measurements. If the measurements are wrong, you probably have to re-install pipes of different lengths or live with the problem.
A few extra minutes of reading the instructions and marking some measurements can save you a big headache down the road.