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Can You Install A Grab Bar In A Fiberglass Shower?

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Your senior parent or loved one is still in good enough health that they can live on their own, but they need more help in the shower. You want to install a grab bar in the shower enclosure, but your senior has a fiberglass shower. Can you outfit the shower with a grab bar?

You can install a grab bar in a fiberglass shower using mounting brackets that are compatible with fiberglass. You’ll have to cut a hole into the fiberglass wall and then drill to secure the grab bar in place.

If you’re interested in installing a grab bar in a fiberglass shower stall, we’ll tell you everything you need to know ahead. Keep reading for grab bar installation instructions, screw recommendations, and tips on how to find a solid mount with wall studs.

Let’s begin!

Can Grab Bars Be Installed On Fiberglass?

You might have heard that installing any sort of grab bar or towel bars on fiberglass shower walls is impossible to do.

Admittedly, fiberglass showers may sometimes have space between the frame and the shower unit itself. That makes installing standard grab bars more challenging but by no means impossible.

However, you do need the necessary tools, which we’ll recommend more in the next section and in the one after that, especially.

Using toggle bolts or mounting wings or other such attachments is not going to get the job done. What you need for installing shower grab bars is none other than mounting spacers and brackets.

The difference between toggle bolts and mounting brackets is this: toggle bolts are fine for installing lightweight shower accessories such as a horizontal bar (like a towel rack).

If you have an adult lean on an attachment that’s held together with toggle bolts, however, the attachment could come right off the wall. That’s not at all what you want for your senior loved ones!

Grab bar mounting brackets are designed for heavyweight applications and won’t buckle under the weight of a person.

How Do You Install A Grab Bar In A Fiberglass Shower?

You’re happy to learn that you can indeed install a grab bar in your senior’s fiberglass shower. How exactly do you do it? Here are the steps to follow – based on using a vertical grab bar.

Buy A Grab Bar

If you don’t already have a grab bar, then buying one is first on the list. Look for one with special mounting plates for fiberglass, such as the Solid Mount mounting kit. These are designed to spread the pressure out so the side of the wall doesn’t crack or break if someone grabs it.

Check The Price

Also be sure that the grab bar has a weight limit that works for your senior. The standard amount of weight supported is 300 pounds, although you can sometimes buy safety bars that will hold more weight.

Grab bar sizes vary: an ideal shower bar has an average diameter of at least 11 ½ inches. If you decide to purchase a horizontal grab bar, it should be at least 32 inches long.

Determine Where The Grab Bar Will Go

This next step will involve you coordinating with your senior parent or loved one. Have them step into the shower where they would normally stand and reach out with their arms. Where would the grab bar be most natural and thus the most helpful to them?

Maybe it’s higher up on the shower wall, or slightly lower down if they shower in a seated position, or even in the center.

The positioning of the grab bar is important, so take some time to get it right. The bar shouldn’t be closer than 1 ½ inches from the wall.

A vertical grab bar should be closest to the faucet handles and the faucet end wall in the bathroom. Horizontal grab bars must be at least 34 inches over the floor and no more than 36 inches.

Feel free to mark that spot on the wall surface with a pencil, as you’re going to have to drill some screw holes anyway.

Find The Stud

Now that you know roughly where on the wall the grab bar will go, you need to locate the closest stud in the wall frame behind the shower (TIP: we’ll go more in depth into how to locate a stud in a fiberglass wall a little later on in this article).

Then, use a nail to poke through the fiberglass to be sure you are in the center of the stud. If you aren’t, move a little to the right or left and try again with the nail.

Once you have located the exact middle, hold the bar against the wall and trace a circle around the top and bottom of the bar to denote where you’ll mount the grab bar.

Measure Between The Shower Wall And The Stud

Next, you want to determine how much space is between the shower wall’s top surface and the edges of the stud that will hold the vertical bar.

Having this measurement will allow you to size the mounting flanges (spacers) appropriately. Feel free to cut the flanges down if they’re too large initially.

Drill A Pilot Hole Into The Studs

Drill a 1/8 inch hole into the wooden stud where the top and bottom of the bar will go.

Adjust the position of the bar slightly to the right or left if you miss the stud, then try again. Usually the mounting plate will cover the incorrect hole.

Install The Grab Bar

Mount the bar with the hardware provided in the Solid Mount mounting kit.

Conduct A Grab Test

You’ll want to be sure the bar will hold if your senior grabs it while falling. The easiest way to do this is to yank on it as hard as you can.

We recommend that you have someone standing next to you, who can help keep you from falling if the bar gives way.

What Screws To Use For A Fiberglass Shower

When you drill the mounting bracket into a fiberglass shower, you have to use screws to do it. The question becomes, which screws are best?

You can choose between two options, decking screws, or fiberglass screws. Let’s take a closer look at each one.

Decking Screws

Although they’re named after their primary purpose – installing deck flooring – decking screws are more versatile than they may initially seem.

A decking screw has a smoother upper shank and coarser threads. This design prevents premature corrosion and/or rust.

Most decking screws are compatible with star-drive or Philips screwdrivers, and they may be self-tapping as well.

For the purposes of installing a grab bar in a fiberglass shower, the decking screws should be at least 1 ¼ inches.

Stainless Steel Screws

Your other option is to use stainless steel screws or fasteners.

Comprised of Inox steel at a rate of at least 10.5 percent, the rest of the screw is a steel alloy. You can select from more than 150 grades to find a durable stainless steel screw that’s right for any home improvement project.

How Do You Find A Stud In A Fiberglass Shower?

As we’ve made clear, you should anticipate locating at least a couple of studs in your senior’s fiberglass shower as you install their grab bar. How will you know how many studs the shower has when you can’t see any of them?

You might not be able to look through walls, but a stud finder can.

Also known as a stud sensor or stud detector, a stud finder is a tool that can determine where studs may be hidden.

As you hold a stud finder up to a fiberglass shower wall, the resins and fibers in the fiberglass can unfortunately make a stud finder less effective, but the fiberglass won’t make the stud finder completely ineffectual.

Ideally, you want to focus on drywalled areas, as there are fewer disruptions, so the stud finder can work more efficiently.

To use a stud finder, turn it on, raise it to the wall, and move it very gradually. When you hear the device beep, then it’s located a stud edge. Be sure to mark the location of the stud edge.

Where one stud edge is, another is usually not too far behind!

Once you have several adjacent marks, use a measuring tape to determine how much space is between them. Usually, it will be 16 to 24 inches.

Now that you know that, if you are installing a horizontal grab bar, finding subsequent studs across the rest of the fiberglass shower shouldn’t prove as challenging.

How Do You Remove A Grab Bar From A Fiberglass Shower?

Perhaps your senior didn’t like showering with a grab bar after all. Maybe they’re moving, and you know that the presence of the grab bar can reduce the home’s curb appeal.

Either way, you want to get rid of the grab bar that you installed not too long ago. How do you detach it from a fiberglass shower wall without damaging the wall itself?

Here are the steps to follow.

Unscrew All Screws And Remove The Grab Bar

Go one by one and, using a screwdriver, loosen every screw and nut that’s holding up the grab bar. You should be able to loosen the bar and potentially remove it entirely.

You can loosen nuts by turning the screwdriver counterclockwise.

Patch Up The Wall

You’re going to see screw marks and drill holes where the grab bar was. These both detract from the appearance of the fiberglass shower wall considerably.

You can try using an acrylic-silicone caulk or an epoxy resin to remove traces of the drill holes. Follow the product instructions so the caulk or epoxy is allowed the proper time to fully dry.

When you’re done, sand over any remaining residue until the area looks smooth. You may want to further treat the area with a layer or two of epoxy paint.

Do Suction Grab Bars Work On Fiberglass?

You may be wondering if you can skip all the fuss of installation and just put up a suction shower grab bar. But, do suction grab bars even work on fiberglass?

The short answer is: it depends.

Suction grab bars rely on suction cups to create a strong hold on a smooth, non-porous, flat surface like tile walls or fiberglass.

In order for this type of grab bar to work properly on fiberglass, the suction cups must have a good seal. If they don’t, the grab bar may come loose and cause you to lose your balance and fall.

To help ensure a good seal, make sure the suction cups are clean and dry before attaching them to the fiberglass surface.

Well, there are certainly some potential benefits to suction grab bars, as they offer a firm grip that is suitable for old people with weak or aging hands (make sure to get one with extra strong suction).

These suction cup grab bars can also be easily installed and moved around as needed, making them an excellent option for seniors who should take some safety measures in the home.

However, there are also some potential drawbacks to suction grab bars. One of the main concerns is safety, as suction cups won’t bear much weight and may not be strong enough to support an individual’s movement.

Additionally, suction grabs can sometimes detach from the wall before they are meant to come off, which could result in injury or further loss of balance.

So, while suction grab bars may seem like a good option for seniors, it is important to carefully consider all the risks associated with these devices before choosing whether or not they are right for your particular situation (check out our grab bar recommendations here).


Installing a grab bar in a fiberglass shower is suitable for seniors who can’t stand steadily for long periods anymore. Although fiberglass is challenging to work with, by following the advice in this article, you can install a grab bar in a fiberglass shower!

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