Sink needs sealing

[Flatfive]

We have a 2019 Thor 24’ Class C motorhome that we just bought. It had previously been a rental from El Monte RV.. All is good mostly. The kitchen sink, however needs some work. It is stainless steel and an under counter type. There is a gap all around the sink where it meets the particle board counter top. There has been water getting in there and now the particle board is swelling up and making a bigger gap. I could just scrape it out a bit and cover the gap with silicone caulk. A better fix would be to remove the sink and abrade away the swollen particle board, replace the sink and then seal the gap. Has anyone had this issue and fixed it?

[Flatfive]

Okay. Here it is two years later. The countertop is continuing to swell. The thin skin is even coming away around the sink. I want to replace the sink with a top Mount sink. Looking on Amazon, I found the very sink I have and it looks like it was meant to be a top Mount and Thor put it underneath the countertop. I wonder, do any of you have a Thor with a top-mount sink? Maybe the installer just put it in wrong!

[StirCrazy]

no, they didn't put it in wrong, you just waited two years to do anything after you noticed a problem.  with moisture you can't wait that long.  

at this point you can take the whole top off as your not going to stop it now, get a sink of your choice and reinstall anything.  

If you decide yo go with a top mount then make sure you seal the edges very well, even the exposed edges where you cut out the sink so they don't adsorb moisture.

  if it were me I would take that counter offand take it to a place that does countertops,  and see if they have a synthetic stone cutoff that works for cheep then you never have to worry about swelling again.  if you use the same sink as a undermount the part they cut out for it can be placed inside as a cutting board/work space expander, but make sure you tell them that.  doing this will make it so you never have to worry about moisture again at that sink.   I don't know why anyone uses particle board anymore, thats the cheep part, not how the sink is mounted.

[jeromep]

I think a better project would be to remove the entire countertop and replace with something that is solid surface. You'll use the existing countertop as a template for the solid surface replacement. When you are done you'll have something that looks great, is impervious to water and you can remount the undermount sink and use this as an occasion to replace what is probably a less than stellar kitchen faucet with something nicer looking and with better utility. It will be a bit of work, but you probably won't deal with this again.

[Lantley]

Before I replace the counter I would repair the area as much as possible and install the sink with some sort of bracing or pressure applied from beneath the sink to support the sink from below

[Gjac]

When I bought my MH in 2004 the counter top was swollen due to water getting in and the partial board swelling. What I did is to remove the Formica trim make some saw cuts in the swollen area to remove some partial board put some wood glue into the cuts then clamp the board to bring it back to its original thickness. The next day I added wood trim instead of the Formica trim. I would do a localized fix first rather than replace the whole counter top unless the whole area is swollen.

[bobndot]

Yes. I would also replace the countertop. There is a thread on someone doing it and it seemed easy enough to do.
You could try to do a fix like you said, see if you’re happy enough doing that.

Here is the real nice job that one member did.

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29816262/print/true.cfm

[way2roll]

Depending on the level of experience you have, the correct way would be to replace the countertop altogether. The particle board is already compromised. This will allow a fresh, smooth surface to re-mount the sink. Countertops are pretty cheap at Lowes and there's not much of it in an RV. Also a thought to consider, does the sink have to be an under mount? While it might require swapping out the drain line, you could mount it conventionally on top and eliminate having to deal with it again. Rv's bounce around a lot and and undermounted sink just seems like it's asking to pull apart again.

[MFL]

I have not had this issue, but sounds like you are answering your own question.:)

I would remove the sink, repair the damage, so counter is level. Without seeing the damage, I'd suggest using a thin layer of plumbers putty tape on the edge that the sink will sit on. After installing the sink, the putty may ooze from compression. This makes a good seal, just needs trimming, and no more water should get back under.

Jerry