Seam Question

[dixie_flyer]

I just had a granite countertop installed, and at the seam one side is slightly higher than the other in the middle part of the countertop. It looks like one of the pieces of granite is slightly bowed and the adjoining piece is not. You can set glass on the countertop right at the seam, and it will rock a bit from side-to-side. The height difference between the 2 pieces of granite is the width of a baseball card, which I believe is a hair less than 1/32 of an inch.

I was wondering how common this is? The installer says that if I want he can level it by surface polishing it, but I wonder how successful that will be.

Any comments will be appreciated.

Thanks,
Wade

[Matt Lansing]

Hello Wade and welcome to our forum!

Unfortunately is can happen with granite. It can be that one top is bowed up or the other is bowed down or the combination of the two working against each other to creat the out of level seam.

When slabs are cut out of the block of stone, the large saw blade tends to follow the path of least resistance. If there was a maginally softer area next to a harder area in the block then the blade will deflect slightly toward the softer area creating a bow in the slab. When the slabs are then polished, the polishing heads at the quarry polish based on pressure so the polishing heads will just follow the contours that are already present in the slab.

This is the condition that the slabs show up to us fabricators in. The bow in the slabs will be so slight most of the time that it is not detectable in the shop. It is once the tops are taken and installed that the bow shows itself when butted up to another piece.

If your fabricator is experienced enough in surface polishing and has been extremely sucessful before then he can attempt it but in most cases you would actually be better off and it will be less noticeable to leave the seam as is.

Otherwise it may be possible to reset the seam so that the front of the seam at the polished edge and the middle of the seam are flush and to let the back of the seam where the counter rarely gets used is left to run wild.

[Andy Ross]

Totally normal with natural stone. it can be top polished out, but I would check up on your fabricator to see if that is in his skill set. It takes practice to top polish well and a poor top polish will be far worse than the slight lippage at the seam.

[CustomMarbleGranite]

What are you using to set your seams? We use gorilla grips and find the cams useful in taking out lippage like this. Top polishing is definitely an option as long as the person doing it is extremely qualified. If its not done properly it can definitely makes matters worse

[Andy Ross]

Even with Omni Stealth or Gorilla Grips, there is some lippage. There is always lippage unless you top polish. The lippage is usually insignificant to most people.

[dixie_flyer]

Hi all,

Thank-you for your responses and for the welcome to the board.

After reading your posts and after thinking about it some more, I'm now leaning toward not doing a surface polish. The installer told me that there would be a slight chance that the surface polish could result in the finish being "hazy" or "cloudy", although he did not think that would be the case.

The lippage isn't really noticable when you look at the countertop (see photo below), but you can feel it with your hand and you feel it if you slide a glass across it.

[Dan R.]

Have your fabricator look us up, we can offer assistance, so that there will be no cloudiness.

[Andy Ross]

I'm happy to help your fabricator as well, but I don't think a top polish is worth it.

[ash20ash]

Have your fabricator look us up, we can offer assistance, so that there will be no cloudiness.

x2 Best for you and him.

Where are you located? Could be a helpfull hand very close by

[dixie_flyer]

Hi Chris -- I'm in St. Louis, MO

[BellaTerra]

That seams to look pretty good especially with the camera angle looking right down at it. In the moment it can certainly seem like a big issue but give it a few days I would bet that the overall beauty of your kitchen granite will cover over any minor flaws. Enjoy your new kitchen!

[dixie_flyer]

That seams to look pretty good especially with the camera angle looking right down at it. In the moment it can certainly seem like a big issue but give it a few days I would bet that the overall beauty of your kitchen granite will cover over any minor flaws. Enjoy your new kitchen!

The seam looks fine, so I have no problem there...I now think that I'd be better off to leave well enough alone and not do the surface polish...I'm happy with the way the kitchen looks, although I'd be even happier if the top didn't have the lippage at the seam...anyway, thanks for your input!

[Dan R.]

Lippage is a relative thing. Consider that the fact you can discern a strand of human hair on a piece of glass, with the touch of your finger. That is quite a high standard for one of the world's hardest materials. Enjoy your beautiful kitchen!

[pkomorowski]

Marble Institute of America manual has a good definition of what is considered acceptable and typical on a granite countertop install.

10.3 Lippage. The term “lippage,” as used
in the stone industry, is the planar offset of the
finished surfaces of two adjacent stone units.
Due to the relatively tight seams used in
countertop installations, even minor amounts
of lippage are noticeable. Lippage may be
unavoidable due to permanent warp in the
slab stock. There should be no detectable
lippage at the front or rear edge of the
countertop. Maximum allowable lippage at
the center of the countertop is 1/32" (0.8
mm).

Based on the MIA manual, it sounds like your seam is within those standards.

As Matt Lansing stated, lippage is sometimes unavoidable. Surface polishing the seam area can be tricky and can't be done by everyone, so if your fabricator isn't confident that he can do it on this stone then I think you're better off not having it done. If it really bothers you then you can alternatively contract a professional that will guarantee that he can match the gloss level on the polished area.