If you’re sealing a bathtub drain, is it better to use plumber’s putty or silicone? The answer depends on the drainage pipe.

You need to know exactly where you’re sealing to determine which material works better.

As a general rule, plumber’s putty is ideal for simple drain projects. It molds more easily than silicone and creates a watertight seal with ease.

But if you’re going to be sealing any piping, you should definitely be using silicone instead of putty.

When To Use Plumber’s Putty or Silicone

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To figure out which material you need, you’ll need to find the access panel of your bathtub. It’s typically below or beside the tub.

When you open the panel, you can get to the pipe underneath the bathtub drain.

For the drain itself, plumber’s putty is the best solution. The material makes waterproof seals with wet surfaces.

If you need to seal the drain pipe, though, you’ll want to use silicone. Caulk is important to sealing pipes because it creates watertight seals that don’t wash away.

Using Plumber’s Putty

Anyone who’s done DIY home improvement projects is probably familiar with the concept of plumber’s putty. This putty is thick and easily molded, somewhat like clay.

You can use it to create a waterproof seal over the drain of your bathtub.

You’ll need to do some disassembly and reassembly to make the putty work properly, though.

Plumber’s putty is a popular choice for basic drain sealing operations because of how easy it is to work with. You can simply mold it to whatever shape you need in order to get the correct seal.

Keep in mind, though, that you absolutely cannot use plumber’s putty to stopper leaky pipes. You can stretch it over the wide mouth of a drain, but if you use it for a pressurized water pipe, that’s a recipe for disaster.

Pros and Cons

Pros:

  •    Easy to mold to unique shapes, so it fits the drain well
        
  •    Dense enough to stretch across wide gaps
        
  •    Great for use on the drain itself

Cons:    

  •    Using it for pressurized pipe sealing is dangerous

How To Apply Plumber’s Putty

Below the drain, you should find a nut that’s been used as part of the installation. Take this out.

This will loosen the drain lip.

You can typically find the nut on the part of the drainpipe directly below the bathtub.

After you’ve unscrewed the nut and loosened the drain, follow these steps:

  •    Squeeze out putty and roll it very thinly.
        
  •    When the diameter is about 1/4th of an inch, roll this around the drain lip.
        
  •    It will create a watertight seal to prevent leaks in the future.
        
  •    Put the nut back in and tighten it.
        
  •    This will tighten the lip of the drain around the putty so you get a tight seal.
        
  •    Wipe away any excess putty around the drain.
        
  •    Allow the putty to dry for maximum effectiveness.

Using Silicone

Silicone caulk is a material with a variety of uses around the house. Unlike plumber’s putty, it can be used to stopper leaks in pipes.

So if you’re going to seal a leaky pipe below your tub, make sure you get out the caulk gun.

Some people might use a combination of caulk for the piping and putty for the drain. It just depends on your personal setup.

Silicone caulk seems similar to rubber when it hardens. It will retain its shape against a pipe and will not wash away with water pressure.

This material is superior to acrylic caulk because it retains its waterproof barrier and doesn’t distort for the majority of its lifespan.

Like plumber’s putty, silicone caulk is often used in wet areas of the bathroom or kitchen. Some people also use it for outdoor protection.

The biggest drawback of silicone is that it’s flexible and not very moldable. Putty can be squished thickly into a drain, but silicone is more likely to flatten and break in the same area.

It works better for smaller cracks than large gaps.

Pros and Cons

Pros: 

  •    Can be used with bathtub drain piping to seal leaks
        
  •    Creates a watertight surface that doesn’t wash away

Cons:

  •    Not as flexible or maneuverable as plumber’s putty
        
  •    Difficult to fit into wide gaps or irregular spaces like open drains

How To Apply Silicone

Silicone is typically used when you can’t put putty around the drain lip, so you need to caulk the drain pipe instead. Follow these basic steps for setup:

  •    Remove the drain cover by loosening the screws and lifting it up.
        
  •    Unscrew the drain pipe and remove it.
        
  •    Inspect the pipe for damage, then scrape away any buildup and caulk.
        
  •    Make sure the drain threads are undamaged, as this is necessary for a proper seal.

Now that it’s time to actually caulk the pipe:

  •    Use a utility knife to cut off the tip of a tube of silicone.
        
  •    Insert the tube into a caulk gun and then snap it into place.
        
  •    Squeeze a small amount of caulk around the drain pipe.
        
  •    Screw the drain back together and tighten it as much as possible to make a waterproof seal.
        
  •    Once this is done, wipe away any excess caulk that oozed out.
        
  •    Use a hammer and screwdriver to tape the drain clockwise until it’s completely tight over the pipe.
        
  •    Put the drain cover back on.
        
  •    Wait for the caulk to dry before using the tub.

Conclusion

Plumber’s putty and silicone can both be used to seal a bathtub drain. Neither is inherently better than the other.

Instead, each has specific advantages and disadvantages.

If you’re sealing a large gap around the mouth of the drain, putty works best. It can be molded into a thick shape that stretches around the entire hole.

Manipulating silicone in this way is more difficult.

If you’re sealing part of the drain pipe itself, plumber’s putty is useless. In fact, using it with pressurized water pipes can actually be dangerous.

You definitely want caulk in this case, since caulk works well for smaller cracks and crevices.

Both materials create smooth, waterproof seals. Both are favored by plumbers for use in bathrooms and kitchens, since they don’t wear down when exposed to moisture.

If you want to know which to keep on hand in your DIY bag, the answer is that it’s better to have both. That makes you a lot more versatile.