My wife an I had a new quartz counter top installed in July. In autumn the seam between two pieces expanded and if there was a sealant between the two pieces to also separated. With further weather change its now moved closer together. I need to glue/seal this with something but I don't know what to use. The gap seems to small for silicone calk. Any ideas on how I fill/seal this?

Countertop Seam / back sink Countertop Seam / front sink

Thanks, Craig

  • 4
    I would call the installers. They should have put an epoxy essentially gluing the pieces together. There shouldn't have ever been a gap. – DMoore Dec 10 '14 at 19:44
  • They did use an expoy at installation. Obviously it wasn't strong enough to hold. I'd love for him to come back but he's not been responsive so I'm hoping to rectify myself. – CraigPDX Dec 11 '14 at 21:02
  • Do you have a picture at both times or at least now? – DMoore Dec 11 '14 at 21:22
  • Pictures added to the original post. – CraigPDX Dec 15 '14 at 17:54
  • 2
    If the installer is really not responsive, might be worth getting your local Better Business Bureau or other consumer protection organization involved. – gregmac Jan 14 '15 at 19:19

This looks to be a bad install. The gap seem too large and that is with the epoxy filling it. When a good installer deals with seams there is a process where they will clamp each side (suction cups or other methods) to push the pieces together. They will add the epoxy in before sandwiching and then scrape off and level the pieces. For different types of countertops they might leave this like this for a day.

I see a wide epoxy seam, which means they did use epoxy but they didn't jam the pieces together. So what happened is epoxy was put in (all the way through I am not sure about), then they fit the two pieces, pushed them together, then the epoxy pushed them apart... very little but enough for it to crack later.

The next issue is that these pieces should have been secured under the slabs to the cabinets in multiple places as close to the seam as possible and as close to the seam as possible. I don't buy that this is normal, because I have seen it done right and have moved two pieces that were seamed together in my house to install new lower cabinets (the seam never broke).

What should you do now? Call the installers. If this isn't an option you need to buy a knife grade epoxy kit. You can match your color or go clear. If you have trouble finding these please let me know and I can look online. (Probably won't be at big boxes) Also if you are just going to lay some epoxy on here it can look nice but probably won't be permanent but is literally a 10 minute job.


Assuming this is a gap that was only closed when the parts were installed, silicone would be the way to go. However, it did not separate on its own. There must be something else moving, such as a (possibly wooden) base it sits on. You might want to check what has caused the crack to open, otherwise it might be a returning problem.

Now for the fixing the gap: there exists a type of construction silicone that you can actually use to hang pieces of stone with. (15mm wide plane for silicone, suspending at least 50cm of stone). This type would definitely be strong enough. Try to contact the installer for any color he uses, or try some samples to find the right color. Wait for the silicone to harden, as the color might change while hardening.

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