[rbyham]

I have about a 12" long crack in the middle of the floor of our head/shower area. It is a fiberglass pan that evidently had a void under it in the center which over the years opened up and has grown to this fairly large crack. The floor being about 3x2' I thought I would one large piece of cloth and just fiberglass the whole floor so as not to show a patch. My questions are:

1. Should I open the crack first and pump something underneath to fill the void first? If so what should I use?

2. Is this a job for fiberglass or is there some better appraoch that would work on the crack?

3. I know almost nothing about fiberglass cloth or resins. If that is the way to go, what would folks here recommend?

Thanks...

 

[mike dryver]

I would think you would have to grind it out! But 1st I would try to get a peek under it somehow! IE through where the head sat! Use your cell phone camera to take pics or just look with the lens! You will definitely have to reinforce under the crack before you tackle the top. The other option is to peel the top layer of the pan and re-core, and then put a new top layer! You could probably use the old skin after you repair it from under, but it would be a lot easier to just lay in new.

 

[rbyham]

I have pressed around the crack and the void is only about 1/4" deep and left and right of crack about 1" in either direction. So basically the floor is well supported except right at the point of the crack. I was thinking either to pry the crack open and squirt some of that Great Stuff foam insulation inside or grin it out to much wider gap and starts with smaller building up to larger layers of cloth... is GS the right thing to inject or is there something else that could fill the void below?

 

[SHNOOL]

I'd cut out a section, figure out what's below it, level it proper, then reglass it... fiberglassing is easy.. its the gelcoat that's the pisser.

 

[ftldiver]

I would not use great stuff , its open cell foam and will smell.

six10 epoxy - calking tube, or open it up.

fwiw, HomeDepot FRP are smooth on one side and crushed ice on the other, makes nice covers for rough bulkheads/bilges or showers.etc

4 ft. x 8 ft. White .090 FRP Wall Board-MFTF12IXA480009600 - The Home Depot

 

[rbyham]

I do have half a tube of six 10 left. Will look again at crack tomorrow to see If I can inject somehow... I agree the void needs to be filled...

 

[Faster]

I do have half a tube of six 10 left. Will look again at crack tomorrow to see If I can inject somehow... I agree the void needs to be filled...

Try to make sure you're not going to block a drainage channel (to the bilge from forward) by filling that 'void'....

 

[rbyham]

Good question but that will not be an issue...

 

[seaner97]

I'd grind it out so you can get your hands in, cross support it with some marine ply strips, then level and glass the whole thing over. It'll be stronger than it started and you will never have to do it again. If you don't properly support it, the crack may reopen as you haven't really fixed the issue- which was the lack of support in that area.

 

[Omatako]

From the lines both left and right as well as the shape of the small bulkhead on the right, I'm confident in saying that the floor changes plane and that the crack is on the line where that change happens.

If I were doing that repair I would roughen an area 6 inches either side of the crack, the whole width of the panel and using some chopped mat and epoxy, lay a patch over the crack. The repair can then be faired and the whole area repainted in the same epoxy. The only load the floor is going to support is a human's body weight which when faced up to the strength of such a repair is paltry.

What is underneath is always going to be underneath. If you're worried about something important rotting down there, that's different. But if you're reasonably indifferent to the "underworld" other than support for the repair, fix it from the top and move on.

Just my opinion but that's what I'd do on my own boat.

 

[rbyham]

True... the crack marks the point at which the floor begins to turn upward following the curve of the hull. From the doorway to the crack the floor is basically flat. I think the idea of patching 6" either side and over coating whole floor with matching paint is a good one but I am goign to add to that by injecting a solid dose of six 10 beneath the crack to see if I can get a bit more support and strength... hope to post pics soon... just got drain rebuilt today.

 

[krisscross]

I would consider patching up the crack with cloth and resin, and then laying a thin (flexible) sheet of plywood set in more resin (on top and bottom) for added support. I would not fill the void under the crack as it may be needed for a proper drainage of that area into the bilge. Water from condensation or leaks has to have a way of draining away.