Quck answer
If your bathtub spout does not sit flush with the fiberglass, there are a few potential solutions.
1. Tighten the spout: Use a wrench to tighten the spout onto the pipe.
2. Replace the spout: If tightening doesn’t work, you may need to replace the spout entirely.
3. Use plumber’s putty: Apply plumber’s putty around the base of the spout before tightening to create a watertight seal.
4. Consult a professional: If the issue persists, it is best to consult a professional plumber who can assess the problem and provide appropriate solutions.
If your bathtub spout does not touch the back wall of the tub, it is likely that you have chosen the wrong type of spout. However, even if that is not the case, the solution is relatively simple. The most common spout has screw threads for the pipe nipple that extends from the front wall, where the water comes out.
However, some spouts have these threads near the back, and such spouts will not fit on a nipple intended for the former type. If your spout has threads near the front or is a slip-on spout, and it does not sit against the wall, it means that the nipple is too long and needs to be either cut or replaced.
Three Categories of Bathtub Spouts
A bathtub spout is hollow inside, except for a connector that is welded to the sides. This connector typically has 1/2-inch female pipe threads, which means that the pipe protruding from the wall, called a nipple, must have 1/2-inch male threads. Some spout connectors are slip-on and connect to a smooth 1/2-inch copper pipe. They have a set screw that you tighten with a Phillips screwdriver or an Allen wrench to secure the spout in place.
The most common spout has threads near the front of the spout, and if the spout has a diverter, it is also near the spout outlet. Less common are spouts with connectors set near the back, and you can identify these by the fact that the diverter is also located near the back.
The third type of spout, known as the slip-on, has an internal water passage into which the copper nipple fits. If it has a diverter, it is near the front. You can easily identify a slip-on spout by looking for the set screw on the underside near the wall, which is absent in a screw-on spout.
Long Threaded Nipple
The galvanized steel or brass nipple for a spout with a threaded connector near the front should ideally be around 2 to 3 inches long. If it is slightly longer, the spout will not sit flush. You can try tightening the spout a bit more, but this is difficult and risky. It may damage the threads of the spout or nipple.
A better solution is to unscrew the nipple, which is connected to an elbow just behind the wall, and replace it with a shorter one. According to EMI Supply, pipe nipple lengths vary by 1/2 inch. So, if you have a 3-inch nipple that is too long, replace it with a 2 1/2-inch one. To do this, unscrew the nipple with a nipple extractor and screw in the new one. Don’t forget to wrap plumbing tape around the nipple threads before screwing it in.
Some spouts come with plastic extension nipples, as described by Danco. If you replace a conventional spout with one of these, you may also need to replace your existing 2- or 3-inch nipple with a 1-inch one to ensure that the spout fits flush against the wall.
Extending the Length of a Slip-On Spout
Typically, a slip-on spout is attached to an unthreaded copper pipe, which is soldered to the elbow behind the wall. Replacing this connection can be difficult. However, if the pipe is too long, there is no need to replace it; you can simply cut it. To achieve a smooth edge that easily fits into the slip connector, it is recommended to use a tubing cutter instead of a hacksaw.
