Both the granite countertops I had up until 2 months ago and the quartz countertops that replaced the granite have inside rounded corners. Never gave it much thought but perhaps one of the fabricators on this forum can offer an explanation.

Yes I would love to hear one of the fabricators thoughts. Id also like to know if this is something that could be changed on site or not

The rounded inside corners are typical. Usually because the tooling leaves it that way and it's more work to square an inside corner. Many fabricators claim rounded inside corners are necessary because of the reasons previously stated. While true in glass, steel, plastic etc. stone is different. Stone is loaded with natural fissures and fractured "grain" structures that will make rounded corners less effective in preventing stress risers. Because no actual testing has proven rounded inside corners prevent or are non-effective in preventing stress cracking in stone fabricators adhere to rounded corners as a precaution. There are many squared inside corners done in stone with no problems. A proper stone install will not have any stress in the corners. If there is stress in the stone it will crack, rounded corners or not.

You have radiused (is that a word?) corners on the outside, and the inside was done to match.

I have mitered edges with square outside corners, so I also have square inside corners.

I am a fabricator.

In the past 10 years CNC finished edges have come to dominate the industry. They save several hours of labor per kitchen at the cost of a finish quality that is inferior to a hands finished edge.

When the edge is a shaped profile like Ogee or bullnose the radius of the CNC tooling (which is a cylinder that is a mirror image of the edge profile) dictates a rounded inside corner. It takes real craftsmanship to hand grind a shaped edge profile on an inside corner.

A flat edge like in the picture could certainly have been a sharp inside corner as it's far easier to finish out by hand than a more complicated edge shape.

Hi, thank you.guys.

Oldryder, Thank you for your response. If I understand correctly having the inside corner rounded was just easier to do and that is why he did it. Now that the counter is on, is it possible to square off the edge in my house?

Errant, I should have specified that the picture I uploaded was in my house as I am not living there yet and didn't have a picture. I did stop by today and took some pictures. As you can see the outside corners are much less rounded then the inside corner.

Here is the inside corner

And here is an outside corner

This post was edited by jdubs79 on Wed, Apr 9, 14 at 16:24

I have a G-shaped kitchen, so I have three inside corners, none of which are rounded. I'm not sure if that's a good thing or not. :) I think I would have been mildly annoyed if they'd been rounded and would have probably gotten over it.

Linelle, yes I will definitely get over it, it's just not what I was expecting and is something I would like fixed if possible. Definitely not the end of the world though.

I take it you didn't discuss the inside edges at templating time? My fabricator asked before I could tell them that I absolutely did not want a radiused inside corner. I specifically requested the outside corners be very square, just barely rounded, and chose an edge as close to square as they are comfortable doing with marble. An rounded inside corner would have spoiled the clean-edged, straight-line look for me.

On the up-side, your stone is really gorgeous! I can't wait to see more.

It can be squared-off in place, I know this, because our fabricator originally gave us a heavily radiused inside corner which we certainly did not want, and we had them cut/reshape the corner the day the counters were installed. They covered the cabs below with cardboard, and cut back the radius into a "soft" 90-degree corner (which is what we had wanted, and thought we were getting in the first place).

I will warn you, you might not end up with as nice and as straight an edge if they do this onsite/with the granite installed (if you look down the length of our counter, you can see it's not quite straight as it nears the corner). Also, I had to have them come back a few times to "fix" or "finesse" the slight bevel (at the top and bottom of the eased edge) on the section of counter between the corner and the range to match the rest of the counter(s).

It's not perfect, and nobody but us, and a good friend who's an architect would notice it unless looking for it. It would have bugged us even more to have that huge radius, which not only did not provide the look we wanted, also took up more space in the corner than we wanted to give up (that's my prime prep zone--right near the range).

No we didn't discuss the corner, I just assumed it would be straighter.

Thanks for the compliment on the stone, once it is finished I will definitely post pics.

I am happy to report that the fabricator was able to square off the inside corner and it looks wonderful!

Wonderful news!

Pics, please!

This is the only pic I have. You can make out the corner in the back but I don't have a close up yet.

Now I have another question. As you can see from the above picture we have a 12" overhang on two sides of the island. My fabricator said I did not need any supports (corbels, etc) but in reading these forums I am seeing that supports are recommended for anything over 10 inches. Will this be ok without supports? Would it be possible to put supports in when the counter and cabinets are already installed?

*whew*

Glad they were able to redo/correct it for you.

What a wonderful update! So glad they were able to fix that corner for you, it's looking great.

I'm not sure if supports are needed or not for your island, we have a similar sized island and have 4 supports on our 12" overhang. I hope someone who knows posts soon for you. :)

The industry trade group MIA (Marble Institute of America) allows an unsupported overhang up to 12" so technically you are OK. In my experience, on many stones, this is too much because of fissures in the stone. In some instances we will rod the overhang which doesn't improve the strength significantly but it does prevent a broken piece from crashing to the floor on to a foot or a kid,

I'd do 12" overhangs on quartz all day long. On granite we usually encourage the customer to provide some support out to 6 or 8 inches. If the supports are low or zero profile they won't be knee knockers. "Zero profile" supports are actually embedded in the stone and are invisible unless you lay on the floor and look up at the underside of the stone.

Corbels must have structural support in the cabinet to be worthwhile. Often they can't be added after the fact because there isn't any robust structure in the cabinet to anchor the corbels.

Love the kitchen and counters!!! Of course I'm biased in regards to the stone :-). We also said that we wanted squared corners, but to have them soften them up just a tad.

They are like that all around our kitchen with the exception of the stone bump outs around our range. Kind of a funny story, but we actually used one of my sons legos as the guide for that!

Looking forward to more pics of your kitchen!

The bigger the radius, the stronger the corner. Estone and solid surface manufacturers have fabrication instructions that include minimum inside radii.

The pictured corners look good to me.

Thanks for all the help guys! I can;t believe how amazing and helpful everyone has been so far. Hopefully I can contribute soon.

Thanks SO much for this post! I just chose my marble slab today and happened to ask them about inside corners. Like previous posters, I had no idea that I needed to specify that I wanted square inside corners. I was told by our stone people that it's standard to match outer and inner corners, so if you have a soft/rounded outside corner, they match the inside corner to the outside unless you specify that you want a sharp inside corner. These pictures were very helpful, thanks!

I never thought to ask about most of my corners. I did ask for a small radius on my overhang. My family is clumsy and I figured it'd be more forgiving when walked into! My other outside corners are all just barely rounded and my insides are square.

This just happened to me today. they put in my granite and the inside corner is round! I hate it! I have straight edges and square corners, I have shaker style cabinets and wanted a clean crisp look and I got this ugly curved corner. I called them and said no way I need the corner like the edges "square" So I am waiting for a call back but they sounded like they are going to give me a hard time because they said I had to specify that ? Oh boy!

It just happened to me as well! I absolutely hate it! They told me they cannot fix it, they don't have the technology to cut it square...The other way around this would have been "seams" instead. I'm super bummed i'll share pictures soon so that everyone sees why!

Mee-len Dickie:

Yours is a sales expectation problem, not a technical one.

What an interesting thread. My quartz counter has one inside edge, and it is rounded. I really had no expectations as to how such corners are generally treated, had not even thought about it. But when I saw mine, I loved it. I think it looks much nicer than squared off.

I will have to live with it, the sink is sealed in place etc. They can't fix it. They tell me it's the only way, even if it was not shown in the plans. Be aware people, that it could be your reality :( :(

I am a fabricator. If you had a sharp inside corner you would have to accept the risk of a crack developing there. Sharp inside corners create a "stress riser" that makes it much easier for a crack to start. This is why the various Quartz manufacturers have a minimum radius specification. It is something a salesperson should have covered with you. If you were to insist on sharp corners it can be done for the countertops by adding a seam. In your drawing the large "L" pieces could have had a sharp inside corner by seaming it differently. However, to match it on the smaller "L" would require a 2nd seam. For the sink there is not a similar option.

Oldryder, are you talking about a seam like these one?

"Be aware people, that it could be your reality"

LOL.

Mee-len:

Your picture is what oldryder is speaking of and is a method for a sharp corners approved by engineered stone manufacturers.

oldryder Agree

Hello! I realize this thread is old, but we just had new quartz countertops installed in our U-shaped kitchen. Contrary to many on this thread, we actually love slightly curved corners and had requested a 1/2" radius on all corners. Unfortunately, when it was installed, we saw that one inside corner has a slight curve (which is beautiful), but the other inside corner has a seam and is a 90-degree angle. We are very disappointed that the corners don't match, as they mirror each other with a U-shaped kitchen. Can you have a radius inside corner at a seam? Would appreciate any advice. Thank you!

" Can you have a radius inside corner at a seam?"

Yes:

Thank you!

Our fabricator is now claiming that the saws in their warehouse are unable to cut a rounded radius inside corner at a seam. Does this require specialized equipment? Just curious if anyone has heard of this. Thank you!

SM:

Saws do not cut radius inside corners at seams, however, that's no problem for a water jet or a CNC machine. Those machines start a 250K, so I guess that makes them specialized.

Thank you, Joseph! I appreciate the information.