I have been receiving a ton of emails asking me what causes granite to crack. It seems that a lot of my readers are experiencing this problem so I plan to address it. First of all, do you really have granite? You are welcome to send me a picture via email by using the contact form on this website. I will let you know which type of countertop you have and help you with your cracking problem.
Natural fissures, weight, unsupported overhangs, hard hits, hot pots, shims not placed properly, and bad quality stone can cause granite to crack.
Let's break this down even further and understand a few of the most common reasons for granite to crack.
This is probably the most sensitive area of your countertops. The stone has 4 and a half inches of surface in this area along with your cabinets. If a shim is used to support and done improperly it will cause the granite to crack in your sink area.
Be sure to check and make sure that it is properly shimmed and if you have to email me with a picture and I can let you know if it is or not.
Sometimes mother nature gives us an imperfect slab of granite. Other times the slab was mishandled and has resulted in hairline cracks in your granite countertops. It is best to prevent this by inspecting your slab before you purchase.
To do this run your hand and fingers on every square inch of the slab and try to find a crack. Also, use a light so you can visually inspect the slab.
By doing this you are sure there are no cracks or natural fissures and if there are when installed you can have them replace it with new material.
Granite is a rock that has been cut down into flat sheets also known as slabs which allow it to be cut and fabricated to what we all know as granite countertops. Most of the time a crack in your granite is not really something to worry about but can pose a problem.
Granite countertops can crack and will crack under pressure or if hit by something heavy. Most of the time your crack is actually a small granite fissure which you should not worry about unless it is located on any area of overhang such as an island or bar area where if it cracks all the way through could fall and hurt someone.
In this case, it is best to prevent the area from being used and call your local granite shop come to check out the affected area. Most likely you will need to replace this entire section of granite or have someone cut down the overhang to remove the crack.
A fissure is a very light line in the granite that can be visible. The best way to know if it is a fissure is to place pressure on one side of the crack and check to see if the fissure or crack can be felt or if it has expanded.
Sometimes fissures can cause a crack to form in this area but that is not always a reason to be concerned. If you choose the right granite provider they will cut around fissures.
Cracks on the other hand are more severe and should be worked around when cutting the slab. If you are limited on the number of slabs then it is best to find another color or ask that these slabs be avoided.
Cracks are usually very noticeable and you should be able to identify them with your own eyes and they feel a bit more like a crack than a fissure would.
Natural Granite Fissures - Granite is known to have natural fissure cracks which can eventually turn into actual cracks in your granite that you don't really have to worry about unless it is in an affected area as mentioned above. Natural fissures give granite character and normally you do not have to worry about these natural cracks. Your fabricator should have already noticed them and made sure they are not in any sensitive areas such as sink cut out, cooktop cut out, or seams.
Hard Hit - If you drop something hard and heavy on your granite countertops you may end up with a chip or a crack. This is caused by the blow of the heavy object. Granite is a rock so it is not indestructible.
Carried Flat - Granite should never be carried flat for any reason. This can cause injury to anyone carrying or damage to floors or furniture. This can also cause a hairline granite crack that can later pose a problem.
Excess Weight - We love to have a 12-inch overhang on our bars and islands to sit and eat or entertain but this area needs to be protected with ibraces or L-shaped brackets called corbels. This will allow extra weight if installed properly but should not make you think the extra weight on any overhang is ok because it is not. People tend to sit or lean on these areas. This is a very bad idea because the extra weight in a vulnerable area could cause a crack or worse the entire slab to break and fall on someone. I have actually heard of someone sitting on the bar overhang and causing the entire granite piece to flip over onto that person. It is best to avoid this.
Not Shimmed Properly - I see it often, installers are supposed to shim areas that are not touching your cabinets when attaching the countertop to the cabinet. Unfortunately, walls, floors, and homes, in general, are not perfectly level. This can cause a number of issues during the install. Areas like a sink cut out, seam or joints, and cooktop cutouts should be shimmed to ensure that they are not going to be cracked due to any weight in that area.
Be sure to look eye-level with your countertops so that you can see underneath and notice any areas that are not touching the cabinet. This area should have a shim every 1 foot and silicone to hold the shims. I will try to take a picture the next time I go install a countertop job to show you exactly how this should look when done the correct way.
It is always best to consult with your local granite fabricator to discuss any problems you have with your countertops including any worrying cracks you have. You may also contact us with any concerns you have about your countertops. We are here to help people so feel free to ask us anything about countertops. That is what we are here for.
If your granite cracked during installation then you need to have the installers stop what they are doing and call their supervisor. You need to also call the sales rep to explain the situation.
They are required to replace your countertops and it is best that you have the installers remove all of the countertops to take with them when they leave.
PRO TIP: Be sure to secretly record the call and interaction with your installers at this point. You need to be able to reference interactions and calls if there is ever a disagreement and this will ensure that everything is 100% transparent. Don't just announce you are recording and follow the laws of your area to decide on recording or not. (this is not legal advice)
Now that you know what causes granite to crack you should know also It is best to never stand or sit on your countertops where there is any significant overhang of over 4 inches. It is also advised that you check any slab you are having fabricated for your kitchen or bathroom countertops. Rub your hands and fingers across your slab to ensure you feel nothing like a crack that could pose a problem in the future.