Many houses, townhouses and mobile homes have a fibreglass tub or shower surround. This guide walks through the three safe ways to mount one, using the makers' own instructions. It is part of my grab bar installation work.
Can a fibreglass tub surround hold a grab bar?
Not by itself. The anchor makers below list fibreglass surrounds at 1/8 to 1/4 inch thick. That is a thin shell, and there is often a gap between its back and the studs. MAAX's install guide for its fibreglass tubs and showers has installers add wood pieces between the back of the walls and the frame for strength.
So a grab bar in fibreglass has to reach the framing, or use an anchor built and rated for that shell. There are three ways to do it.
- Into wood blocking set behind the surround.
- Into a stud, through the fibreglass, with a kit that bridges the gap.
- Into a hollow-wall anchor its maker approves for fibreglass.
One more check before drilling: the surround's warranty. Some makers exclude grab bars they did not approve. MAAX Aker's install guidelines for two of its tub-shower modules list added grab bars not designed for the unit, or not authorized in writing by the maker, among the things the warranty does not cover.
How do you find the studs behind fibreglass?
Moen's grab bar instructions say to find studs with a stud sensor or another locating method, and that studs are usually 16 inches apart. On a surround, I confirm what the sensor says with a small pilot hole.
When you are not using studs, the search still matters. WingIts' install sheet for its GBW40 fastener says to use a stud finder to make sure no stud sits where the fastener goes, because its wings spring open behind the wall.
Can a grab bar go into a stud through the fibreglass?
Yes, when the bar lines up with the framing. Moen says both ends of its grab bars must sit over a wood stud unless its SecureMount anchors are used. The problem is the gap behind the shell. The screw has to cross fibreglass and open air before it reaches wood.
Stud-mount kits exist for this. The Solid Mount is one. Its maker says it is designed for fibreglass tubs and showers, and that it bridges the cavity between the enclosure and the framing so the load goes into the studs. Kits like this only help where a stud lands under the flange.
Can you add blocking behind a fibreglass surround?
Yes, and it is easiest before the surround goes in. MAAX's instruction sheet for its Olio tub-shower says that if you are adding accessories such as a grab bar, extra framing or backing may be needed for support. That step belongs before the unit is set.
Once the surround is in, blocking can only go in from behind. That means opening the wall from the next room or a closet, or waiting until the surround is replaced. It is the most work of the three, so it suits a bathroom that is being redone.
Every job I take gets a written scope before I start, so the price is agreed in advance and the list stays the list.
Want me to take this one on? My page on grab bar installation covers what the visit includes, what I hand off, and how I price it.
What anchors are rated for grab bars in fibreglass?
Several makers sell hollow-wall anchors made for grab bars and approved for fibreglass. Each one comes with limits on wall thickness, space behind the wall and which bars it fits.
- Moen SecureMount Anchor (SMA1000). Moen's spec sheet lists 1/8 or 1/4 inch fibreglass tub surrounds. It needs a 1 1/4 inch hole and 3 1/2 inches of space behind the wall. Moen rates it "for persons no more than 300lbs."
- HealthCraft Easy Mount Hollow Wall Anchor. HealthCraft's product page lists 1/8 to 1/4 inch fibreglass, a 1.25 inch hole, 3 1/2 inches of space behind the wall, and "a weight capacity of 300 pounds" in drywall, drywall with tile and fibreglass. It only fits HealthCraft's own Easy Mount (Generation 2) and Plus Series grab bars.
- WingIts stainless steel grab bar fastener. The WingIts FAQ says only fasteners with stainless steel wings suit fibreglass, and its GBW40 works in surrounds 1/4 inch thick or more that are not deteriorating.
Each anchor is only as good as the wall it sits in. A cracked, soft or flexing surround is no place for any of them. If the shell moves when you press on it, the fix starts there. Caulking tubs and showers covers the seal that keeps water out of that wall, and I seal every hole I drill.
Are suction cup grab bars safe in a fibreglass shower?
Not as support. Drive Medical, which makes one, says on its product page that its suction cup grab bar is a balance assist only and is not meant to support body weight. It recommends a permanently mounted grab bar for anyone who needs to put weight on it.
Where should grab bars go in a tub-shower?
Put them where the body changes position: stepping over the tub edge, sitting down, standing up. That usually means a vertical bar at the entry and a bar along the long wall. Grab bars and bathroom safety for aging in place covers placement in detail. Moen also tells users to consult a healthcare professional about their own needs, so I follow a therapist's notes when there are some.
What does grab bar installation cost?
My only published price is the $200 minimum per job, and several bars can share it. The rest depends on how many bars, which mounting method each spot allows, whether blocking means opening a wall, and who supplies the bars and anchors. If someone in the house has a permanent disability or loss of ability, the BC RAHA rebate may pay back part of it, but only with approval first.
I install grab bars in fibreglass surrounds across the Fraser Valley. See grab bar installation in Langley, grab bar installation in Surrey or grab bar installation in Abbotsford for how the work runs in each town.
