Fiberglass Bathtub Repair

December 11th, 2011  Posted at   Articles

Fiberglass Bathtub Repair

Accidents will happen and with a thickness of about a 1/4″, even a child can slip and poke a hole in the sides of a fiberglass bathtub with an elbow or knee.  When that happens, its comforting to know that you don’t have to pay to replace the bathtub and that the damage can be repaired.  Here’s what’s involved in the fiberglass bathtub repair process.

This particular fiberglass bathtub/wall unit was in a local motel and had a big hole on one of the side walls of the unit.

First Choice Refinishers - before repair

The repair process includes a double-layer of fiberglass cloth.  The first layer extends beyond the break by about 1-2″, the second layer then extends 1-2″ beyond that.


First Choice Refinishers - fiberglass patch

Fiberglass Double-Layer Patch

Once the fiberglass resin-soaked cloth has dried, which takes about 2 hours, the rough edges are sanded down and then the whole area is filled in with fill (similar to bondo) and then sanded smooth.  This usually requires multiple layers because its better to have 2 or 3 thin layers, rather than one thick layer.

First Choice Refinishers - filled and sanded

Filled and Sanded

Once it has been filled and sanded smooth, the final step is to paint it to match.

First Choice Refinishers - Completed Repair

Completed Bathtub Repair

This is a two-step process, the same used in reglazing a bathtub; (a) 2-coats of primer, followed by (b) 2-coats of the glaze, which is where the color is.  The trickiest part of the whole fiberglass bathtub repair process is the “matching”, especially if it happens to be a white tub.  There is no such thing as “just white” on any color chart!

Tub bottom

If the damage is in the bathtub floor, and especially if you have a heavy-set build, you can take a can of expanding foam (i.e. Great Stuff^) and **fill the area underneath before putting the patch down.  When using expanding foam, keep in mind that it is “expanding” and not over-fill the space.  You can also take a drill and drill extra holes to more easily distribute the foam to a greater area.  (These expanding foams are really designed and marketed as insulation sealants, but cure to a hard surface that works well to reinforce bathtub bottoms.)

Then, the bathtub repair process is pretty much the same.  If the break is large, I will usually use a triple layer of fiberglass cloth, rather than the double used on wall repairs.  You don’t want to use too many layers because you will have a bulge in the area because of the thickness, but the bottom has more stress that must be handled than the walls.

In some cases, a fiberglass in-lay can be glued to the tub bottom to reinforce the entire area.  Its kind of like adding a bottom to the bottom.  The sheet I use is about 1/16″ in thickness and glued to the flat area (the sheet is too stiff to bend into the curved areas) with an epoxy adhesive.  In all the years that I have been installing these in-lays, I’ve only had one occasion where it later cracked.  And, in no instance has the glue failed to hold.


*Great Stuff is a registered trademark of the Dow Chemical Company.

**In reality, the space between the house flooring and tub bottom should have been filled with cement or foam during the installation process, but unfortunately, this is not done in the majority of cases.  If you have questions about a fiberglass bathtub repair, feel free to give me a call, Randy at (919)731-2552, or send me a message.

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