Fiberglass shower pan has small crack; leaks

[Mike from Brier]

I installed a Lasco Fiberglass Shower Pan per the manufacturers directions about three years ago. I used four mounds of mortar for supporting the bottom as described in the instructions, surrounding but not contacting the drain area.

This morning I was in our unfinished downstairs bathroom which is directly beneath the bathroom this shower is in. I noticed a small puddle of water on the floor, and traced it to the area underneath this shower. I could see where water was coming through the car decking (the subfloor for the upstairs bathroom). When inspecting the shower pan I found a crack in top layer of the base, about five inches from the drain. When I press on the pan the crack opens just slightly, so it appears this is where the problem is stemming from. I'm guessing this crack is about 3-4 inches from the nearest supporting mound under the pan.

Obviously the permanent fix would be to tear out the whole thing and start fresh, but is there a temporary fix to repair the crack so I don't end up with a rotten floor under the pan? This crack wasn't there a couple days ago, so I know it hasn't been leaking for very long.

By the way, my neighbor (he makes garden art) makes fiberglass molds for creating his statues. Would it be possible to overlay a few pieces of fiberglass over the cracked area as a temp fix? Any other suggestions?

 

[Dunbar Plumbing]

Yes. You will have to prepare the surface like any other fiberglass repair, make sure it is dry and apply the material to make the repair. There are those who do this for a living that can replicate the finish of the original without having much of a different look. The problem is that there must be voids under the pan where the mortar didn't cover the base evenly. Did you mix up the mortar fairly loose, like the consistency of a thick milk shake? That allows you to build the mortar up fairly high, then slowly bring down the pan while the material oozes out the sides. This excess can then be banked/packed in around the open sides so that the product completely is surrounding the pan. Always put down plastic when putting mortar on a wood subfloor.

 

[Sponsor]

 

[Mike from Brier]

Thanks for the reply. Actually, I know there are voids under the pan, but this is due to the instructions that came with it. Here is a copy and paste from those instructions:

In a bucket, mix foundation material. Place three or four mounds of plaster on the subfloor around but away from drain hole. The mounds should be placed high enough so that when the pan is set, it will cause the plaster to displace and spread. [See Diagram 2]

Place pan into alcove with front skirt firmly on floor and depress plaster mounds. Make certain that unit is level [See Diagram 2]. The pan should be set level.

Diagram 2 just shows the four mounds evenly spaced under the pan, never in contact with each other. The instructions then go on to explain how to fasten the pan to the studs.

Nowhere in the instructions does it indicate that the entire bottom of the pan is to be supported. It made it sound as though the mounds were all the support needed. With that in mind, I called the field service rep for Lasco and explained my issue. He agreed that the instructions are "broadly written", but indeed the entire bottom was supposed to be supported, even though it doesn't specifically say so. So a DIY'er is supposed to get this by osmosis? Needless to say, I'm a little irritated.

Since the pan is out of warranty, he suggested getting a repair kit from GelCoat with everything I'll need to do the fix. He also said that if his repair techs found the pan wasn't totally supported they would drill a 1/4" hole in it and inject high density foam in the area for added support, then proceed with the cosmetic fix. Since a DIY'er probably can't get the foam, he suggested I use Plaster of Paris instead.

Live and learn!!

 

[Dunbar Plumbing]

That's a really good idea with the drilling of holes and filling the voids. That would guarantee the repair from happening again. I have a unit in a property that I did not use mortar at all, and yes, spider cracks all over the bottom. Since I do not use this unit I stay out of it and will not until I support the bottom of the unit. At least you can fix the pan without major reworking of the shower.