A Sink For Every Style, Pt. 3
Once again, every sink should be test-fit dry. Make sure the sink position is correct – labels in the right place, shallow and deep sinks on the correct sides. It’s also the time to make sure you can move your sink to the proper position under the cutout.
Sometimes a cabinet-mounted support board, aluminum undermounting bar or misplaced clip will prevent you from centering the sink where it needs to be. Making an adjustment at this point, while never fun, is much-preferable to scraping silicone off the top of the sink and the bottom of the stone so it doesn’t set up while you make your fix.
Whatever method of sink support you’re using should be tested as well. Having a sink with a glued rim hanging above you is not the time to discover that the screws you were going to use with your anchor are the wrong thread, or are too long to tighten the sink against the bottom of the stone.
Dry fitting also allows you to test each clip to see if it reaches the edge of the sink, and if you can actually tighten it when the sink is in place. Front clips can often be a bear to tighten, and figuring out a strategy to make them work before the glue is on can save you a lot of stress.
It’s also the time to make sure the sink is supported enough to provide a tight fit without relying on adhesive. You’ll be glad you did when a rushed plumber hangs a garbage disposal on your sink five minutes after you set it.
This may mean adding cabinet-mounted support, or gluing in an undermount stud for an extra clip. If the back of a stainless-steel sink sags in the middle, it’s possible to drill the faucet hole and use the mounting mechanism of the faucet for sink support as well. Just make sure to leave a note for the plumber to install the faucet the same way.
My last pre-glue recommendation is to buy, and have at the ready, an undermount-sink installation tool to hold the sink fast against the bottom of the stone while you tighten clips or insert shims. They are inexpensive and are really a must if you have to mount a sink by yourself.
Sliding wood clamps can also work, but if you want to use them for a bath vanity sink you’ll have to grind off the metal bulb at the end of the shaft. This allows you to separate the clamp and insert the shaft into the vanity drain.
There are three things to watch out for when using this tool. First, take care with how much upward pressure you apply. If you tighten the clamp too much you risk damaging the sink, especially a stainless-steel model.
This is especially true when using a sliding wood clamp, because it tends to localize all the upward pressure on one point. Using a board across the bottom of the sink can spread out the force on the sink, but it can be difficult to position right when you’re working solo.
Second, you need to position the installation tool so that the pull is straight up. Having the pull at an angle can slide the sink while you are setting it; discovering this after the clips are tight is a huge waste of time, because you have to loosen them again, reposition the sink, and retighten the clips. Setting the tool and then babysitting it for a minute should show you if the sink is going to slide.
Third, be careful not to use the tool as a shortcut for supporting a sink. You can leave the tool on until your adhesive sets; but, by doing this, you’ll never know if your sink is truly supported or if it’s just glued in place. If you have a corner sag a couple months down the road, you’ll have your answer and a frustrated client.
Once you’ve tightened your clips or put shims in place, remove the installation tool and check to see that your sink support remains strong. If it does, you have a properly installed sink.
With the dry-fit done and an undermount tool at the ready, it’s time for the adhesive. While I prefer to use 100-percent silicone for my granite and engineered-stone installations, this is not the only adhesive that’ll work. As long as an adhesive provides a strong, permanent, waterproof bond, it’s acceptable to use. It should also be aesthetically pleasing, if you want happy customers.
The adhesive should also work with the countertop and the sink. If you are installing a white marble sink on a white marble countertop, keep the silicone away. If you are unsure what adhesive to use with a particular combination, check with the manufacturer.
When installing an undermount sink, make sure to cover the entire rim with adhesive. This will ensure a strong, waterproof bond.
Be as careful as possible when applying the adhesive; dropping globs of silicone into a sink bowl can be a real mess to clean up, especially on stainless steel. If this does happen, the best thing to do is allow them to dry as much as possible before removal. If they have enough time for a dry silicone skin to form, you can usually avoid smearing the globs when you clean up.
The adhesive squeeze-out around the rim of the sink should be cleaned quickly with dry paper towels. For granite and engineered stone, a light acetone wash is a good way to remove the remaining adhesive haze.
Cast-iron and acrylic sinks can be a little more-difficult. Sometimes it will be necessary to apply a second coat of adhesive to fill in voids on the uneven sink top. With poorly cast sinks (which I believe have become more-common), this void can be as big as 1/4”. I highly recommend taping off both the top edge of the sink and the edge of the stone.
For radiused sink corners, you’ll need lots of small pieces of tape. This is a pain, but doing it well makes the fit of the sink look even better. A quality tape job also allows you to apply a liberal-enough amount of adhesive to fill the void, while at the same time not making a huge mess.
When filling in cast-sink voids I try to match my adhesive color to the sink. If you have a couple of colors that are close and you’re unsure, try to get the homeowner to choose. They’re going to be looking at the sink the most, and having them choose the color gets you off the hook.
Once the sink is set and any excess adhesive cleaned up, try to keep the sink dry and free of dust until the glue is set up. If the plumber is in a hurry, make sure to show him where not to put his fingers. If you have to drill faucet holes, make sure to cover any adhesive that is still tacky. Nothing can make almond caulk look worse than a nice shot of stone dust!.
Lastly, carry a digital camera along with you and take a couple close ups of the installed sink. You can put them in your portfolio, and they also serve as proof that the sink was perfect when you left it. If a plumber drops a wrench in a sink and makes a dent, you can’t be blamed.
Installing the sink is the end of a long process. Doing a quality job of it makes the kitchen or bath look just that much better. With the exception of a snack-bar seating area, no spot in a kitchen gets more constant attention than a sink.
If the homeowner can see time and time again that you did a quality job, they may recommend you in the future. That’s how to use a sink as an advertising tool.
Jason Nottestad, a 12-year stone industry veteran, is co-owner of Wisconsin-based Midwest Template Services (www.countertopsbymts.com).