If you’re the do-it-yourself type, then you may have thought at some point or another, “Hey, what if I get a granite countertop and install it with the sink myself? Wouldn’t that cut down on the price?” The answer to that is yes — usually. If you are looking at our granite remnant sale, templating and installation are not included in the special prices you can get through that. So, for the sake of this semi-tutorial, let’s pretend you have purchased a 3cm granite vanity from us, and you have your own undermount sink. The counter is completely fabricated and edged, with a finished sink hole. Now what?
Required materials:
- six to eight 1 1/4″ or 1 1/2″ screws
- two strips of 1″ by 1″ wood about three feet long each
- one piece of 5/8″ plywood, cut to fit inside your cabinet’s top; a little smaller than 3′ by 3′
- one undermount sink with provided clips and screws
- measuring tape
- tracing pencil or marker that will show on plywood
- four 3/4″ buttonhead screws
- Liquid Nails
- one tube appropriately colored silicon caulk
- hand-held jigsaw
The typical cabinet set will have two interior walls between which the bowl of the sink should fit. Doors will be in front of that area, and more doors or perhaps drawers to each side. Inside your cabinet, about 5/8″ of an inch from the top edges of the cabinet, you will need to install a 1″ x 1″ strip along the inside of these two interior walls. You can use one-and-a-quarter inch or one-and-a-half inch screws, depending on the thickness of your cabinet walls. Use two or three screws for each side.
Inside the cabinet top, resting on these two strips, install a piece of 5/8″ plywood that reaches from the front to the back of the cabinet. If necessary, you can put more pieces of 1″ x 1″ stripping in the back corners for more support. Now, you need to measure your sink. The hole in the granite is already the correct size, because you will have provided us with your sink or sink template during fabrication.
You might be able to lay the granite on top of your cabinet to trace the hole directly onto your plywood, but it’s generally a good idea to double check it with the following measurements:
Find the sink’s center line from front to back on your plywood. The location of your sink will depend greatly on this line. Measure the diameter of the sink, both right to left and front to back. Divide the right and left diameter of the sink in half. Make a mark that distance away from the centerline on the plywood on each side. Taking into account the pre-finished hole in the granite, the overhang of how far the granite extends over the front edge of the cabinet, and remembering to include the rim of the sink in your calculations, determine where the front and back edges of the sink will hit the centerline on your piece of plywood. This is the tricky part, so double check your measurements.
Lay the sink face down on top of the plywood, with the back facing the wall and the front towards you. The sink should fit just inside the four marks you have made in each direction on the plywood. When you have it correctly positioned, trace around the sink, adding about 1/8″ to 1/4″ to your circle — no more than that.
Now, remove the sink and cut out the circle on your plywood, including the tracing line, with a jigsaw. Before you put the jigsaw away, you need to use it to cut away the plywood from between the sinkhole and the back of your cabinets, and discard that extra piece. This is where your faucets or valve will be inserted through the holes in your vanity. Be sure to cut away enough plywood for them to fit comfortably inside the hole. The reason for this is that many faucet components are not long enough to screw together properly when the extra 5/8″ thickness of the plywood is added to the three centimeters of the granite. Most faucets will require that you cut away about 5″ from each side of the centerline, but it’s best to measure yours to make sure.
Moving to the next step, using 3/4″ buttonhead screws, attach the clips that came with the sink to the edges of the hole you have cut, at about 1/2″ from the edge. We don’t recommend using the screws that come with the clips, because they are often too long and it becomes necessary to shear off the ends in order to fit the granite over the plywood. Thinking about your hole as though it were marked with a clock face, place the clips at about 2 o’clock, 4:30, 7:30, and 10 o’clock. Be sure the clips extend far enough into the hold to support the sink. Set the sink on the clips. Use a straightedge to ensure that the top of the sink is flush with the plywood on each side.
With liquid nails or another appropriate adhesive, place quarter to half-dollar sized blobs of adhesive about 6″ apart on the substrate, or layer the granite will attach to. (This includes the plywood your sink is set in.) Place a line of silicon caulk around the edge of your sink. Put the granite on top of the cabinet, plywood, and sink. Use an appropriately colored caulk to finish the places where sink meets countertop, and your sink is installed!
As you can see, the process is somewhat involved if you haven’t done if before. That’s why we recommend a professional to install your sink for you. But if you’re hoping to cut down on the bills associated with your new vanity top, we hope this little tutorial come in handy.
Heidi Blodgett
Schumacher Tile & Stone
Professional Consultant on Sink Installation:
Tony Brock
Schumacher Tile & Stone
July 29th, 2009 at 11:33 pm
I follow your blog for quite a long time and should tell that your articles always prove to be of a high value and quality for readers.
August 3rd, 2009 at 1:43 pm
Thank you, we really hope all the information we put on here is useful!
August 5th, 2009 at 5:34 am
Can you help me find DIY resources for driveway construction?
I have a rural property with a large ditch drain out the front (no curb or channel).
August 5th, 2009 at 1:27 pm
Hello, Elijah.
I would recommend speaking with a local cement contractor, or someone who deals with the type of material you’re thinking about using. I don’t know of an application for tile or natural slabs in a driveway – I’m pretty sure the weight would be a little too much for that material. But if you find anything like that, we’d be fascinated to hear about it!