How to remove old & apply new sillicone to 2cm gap edges of a shower tub, with no backing rod?

inkadinkatren · 05-03-2026 01:07PM #1

Hi there,

It's been a while since our tub was installed and we only recently began using it, so the warranty is a no no. I noticed that there's some water leak below so I ended up removing the cover (it's the squared floor type of tub for stading, not surrounded by cement either) and noticed that theres water on the tiles underneath two edges, leading me to realize that the sillicone on those two edges/pvc boards doesn't hold properly.

I asked a few shops near me if they sell backing rod (poliethylene foam), but none of them have it and I'd really like to avoid ordering it online.

I want to know what I can use as an alternative, something that can be easily found, potentially even in grocery stores. I thought about PU foam spray but idk if that would work and in my head I'm still hoping if there's something of a better substitute that can just be placed inside.

Secondly, how do I remove the old sillicone without searching for various chemicals, I have only just a bit of residue left, but I'd like to avoid scrubbing with hard things, soft ones don't help, nor did wd40.

Thank you.

kirving · 05-03-2026 06:10PM

If you can upload a photo, either to here or the likes of imgur.com (and add the link), you'll get better advice I think. I think 2cm is a big gap to fill in a shower, even with a foam packing behind it.

smuggler.ie · 05-03-2026 08:07PM

Wonder if pipe lagging would work for you. 2m lengths and can be easy cut
I seen something in b&q flooring section, sort of similar as pipe lagging, but without hole, ~16mm in diameter. Potentially to fill gap at the floor/wall meetpoint
2cm is huge for silicone bead

inkadinkatren · 07-03-2026 02:47AM

https://www.boards.ie/discussion/comment/124288271#Comment_124288271

https://www.boards.ie/discussion/comment/124288550#Comment_124288550

Sure, here are some pictures. Please don't judge the messy look, I'll clean it all properly once it's solved.

As you can see on the first picture, the water is somehow leaking underneath the sillicone and pvc boards.

On the 2nd picture you can see how much I managed to remove with a razor, the gap and the look of the pvc board. I'm not sure if this is exactly 2cm since I didn't measure it, but it's more than 1 and less than 3. Thing is, I don't see a backer rod underneath, so I'm a bit unsure how the workers did this. My guess is that they applied sillicone to the boards (sorry, idk the exact term), and then quickly placed the boards down - which, if so, doesn't really sound ideal, but I'm just guessing. Additionally you can notice on the third picture that some sillicone appears to be coming out from underneath as a thin strip. Now sure, you probably have to push the board onto the sillicone so it'll always come out, but... should it be this thin? Logically if it's thin and dries it might not hold properly and having to rely purely on the sillicone under the board instead of under and a bit above (a thicker strip?) doesn't seem right. Visually it might be correct but, you know...

These days I'll try to check some stores if they have those cylindrical long foams for swimming. Usually they're from polyethelene so it should work. But if they don't have it, then I don't know what to do.

Pipe logging doesn't seem much different from backer rods and tbh looks like something for more complicated situations. I'm really trying to avoid ordering things online, if there are valid alternatives to be found.

The other problem about getting rid of the old sillicone still presists too.

@kirving

@smuggler.ie

How to remove old & apply new sillicone to 2cm gap edges of a shower tub, with no backing rod?

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