Foam inside shower valve escutcheon

[DannyDan]

Our shower was recently remodeled and I purchased a new trim kit to match the existing valve (K-403K). It appears the escutcheon has a foam ring inside which unfortunately is peeling away (see photo).
I already contacted Kohler for a replacement, but I'm also curious - what exactly is the purpose of this foam? If it's meant to prevent water seeping through, it seems pretty unreliable...
Also, interestingly enough, the installation instructions do not call for siliconing or caulk around it...

Edit: here's the image:

 

[Terry]

I don't see the foam behind the wall plate as doing much of anything at all. I caulk with clear after installation anyway to prevent water from sliding down the wall and behind the plate. I leave out a bit on the bottom, so that if any water does get by, it has a place to drain out.

In the picture above, you can see the notch in the plate at the bottom, and the gap in the foam.
That lets any trapped water out.

In the picture below, maybe that's glowing white is the caulking. I sometimes take pictures before caulking and sometimes after.

 

[Sponsor]

 

[John Gayewski]

Its meant to keep water out. The amount of water, that hits the wall in that area is generally so small most is diverted around the foam and drips from the bottom. That foam should be compressed against the wall when your done.

 

[DannyDan]

Thanks both. So would you say it's worth waiting on the replacement from Kohler or just go ahead and install it as is?

 

[Terry]

When pressed flat against the wall, the foam is going to snug up.