Granite bathroom countertop.

How To Install Granite Countertops

Originally contributed by • last updated 5/28/2021

20 minsPrep Time
30 minsActive Time
EasyDifficulty
Zac Gudakov
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20 minsPrep Time
30 minsActive Time
EasyDifficulty

Have you always wanted granite countertops but have been deterred because of how much installation costs?

Well, no more. We’ll teach you the ins and outs of granite countertop installation so that you can replace a bathroom vanity. 

These skills are transferable if you plan to tackle a more ambitious project, say, a kitchen remodel.

Learn how to measure, install, and attach granite countertops like a professional!

Let's Make It

Equipment

  • Measuring tape
  • Pencil
  • Caulking gun

Materials

  • Granite slab
  • Silicone

How To Measure For Granite Countertops

01/8

Measure The Base

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Start by measuring the length and width of the surface that the granite slabs will cover. In our example, we’re replacing a bathroom vanity countertop.

When measuring for granite countertops, keep in mind that the walls may be slightly out of square. Be sure to measure the front, back, left, and right of the surface for the granite bathroom vanity.

Make sure your measurements are as accurate as possible. For the best results, the cut granite countertop should be perfectly tight against the wall, and taking multiple measurements helps compensate for any irregularities.

Once the measurements are taken, record them on a sketch or diagram.

02/8

Sink Placement

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When sending cut measurements to granite fabricators, you need to include the centerline for the sink.

Info: The sink centerline is the distance from the wall to the center of the sink. To find this measurement, you will need to determine where the sink will be located.

Tip: When creating a granite bathroom vanity, the centerline for the sink looks best if it is aligned with the centerline of cabinet doors. Measure the centerline from the wall to the opening between the cabinet doors.

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Now measure the dimensions of the sink.

Tip: When installing an undermount sink, determine the length and width of the sink from the exposed, finished areas. Don’t record the measurements for the entire sink top, as the rim will secure the sink to the granite countertop. You don’t want that section of granite to be cut away, or it will make countertop sink installation impossible!

03/8

Countertop Overhang

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Determine how much of an overhang you want your countertop to have.

We recommend an overhang of 1¼”.

Once you have decided how much of an overhang you want, add that number to your previously recorded measurements.

04/8

Send Cut Measurements To Granite Fabricator

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With your diagram made and all measurements recorded, send it off to the granite fabricator so the granite can be cut to size for your DIY countertop project.

You can take a picture of the diagram and email it to the manufacturer. 

Decide how thick you want the granite countertop to be, and provide this information, as well.

Tip: It doesn’t hurt to include a legend on the diagram, spend time labelling, and provide the granite manufacture with as much detail and information as you can. Granite slabs can be expensive, so it’s better to ensure all measurements are not only correct but fully understood by the people who will be cutting them.

How To Install Granite Countertops

05/8

Transporting Granite Slabs

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When transporting a granite countertop for installation, make sure you move it vertically on its edge.

Granite countertops are heavy, and if they’re transported horizontally, they can snap as a result of the weight.

They are especially vulnerable near cutouts for sinks.

To avoid damaging granite countertops during your DIY project, life the pieces on their edge.

06/8

Granite Countertop Installation

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Granite countertop installation is a surprisingly easy process. The weight of the granite bathroom vanity is mainly what will hold it in place. 

To start, bring the granite slab to the bathroom countertop. Stand the piece on its edge on top of the vanity.

Slowly bring the countertop down while placing your hand underneath the granite in the middle to give it support. 

Supporting the slab from underneath prevents it from breaking will it’s moved from a vertical to a horizontal position.

Once the granite countertop is on top of the bathroom vanity, slide it into place, so it’s tight against the wall(s). Make sure the wall joints are tight.

How Are Granite Countertops Attached?

07/8

Silicone Inside Granite Bathroom Vanity

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While it’s mostly the weight that will keep the granite countertop in place, silicone prevents movement, as well.

Use a caulking gun and apply a bead of silicone to all the inside seams where the cabinetry is in contact with the DIY granite countertop.

For in-depth information on how to apply silicone caulk, check out our comprehensive silicone lesson.

08/8

Silicone Outside Granite Countertop

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Once all the inside joints have silicone, repeat the process on the outside joints.

We hope this lesson provides you with the confidence for your own DIY granite countertop installation. 

Knowing how to measure and install granite countertops and how they are attached provides you with a cost-effective solution to creating a stunning vanity!