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.
What Causes Granite to Crack
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.
Granite can crack from the following reasons
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 with 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. 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 ever 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.
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.