Drilling Holes in Corian® and
Solid surface... the generic name for a number of plastic resin products used for everything from kitchen or bathroom countertops to shower enclosures... has become the rage in recent years. One of the most familiar of these products, featured in the photo to the left, is Corian© by DuPont. (See copyright notice at the end of this article.)
Solid surface is durable, sanitary and non-porous, making it a great choice for kitchen or bathroom countertops. Unfortunately, do-it-yourselfers face a dilemma. Though many kitchen and bathroom sinks have predrilled holes, this is not always the case with Corian® or other solid surface products. One reason that many of these countertops come "hole-less" is because of the growing number of sink faucet configurations. It is not uncommon to find 8" centers on bathroom faucets... the old standard for kitchens... as the size of the modern "throne room" (or library, if you will) continues to increase. Hey... some bathrooms today are larger than the kitchen in my first home! Now that I think of it, the living room too!
Not to worry... Corian® is drillable with standard drill bits and hole saws and is moderately difficult to break. However, you must be careful not to mar the surface when drilling.
Lay the countertop/sink across a solid pair of sawhorses. Apply some masking tape to the countertop in the approximate location of the faucet. Be generous in your tape coverage; however it is unnecessary to apply multiple layers of tape. The purpose of the tape is to offer a little protection to the countertop and to give you a better surface to write on... pencil marks can be almost impossible to see on some countertop patterns! The "blue" tape shown in the graphic is a special low-tack painter's tape. It's easier to remove than regular masking tape and is also more photogenic!
Since the actual "underneath" edge of the "integral" sink is not apparent from the top-view, don't assume that giving an inch clearance from the top edge of the sink is enough... you may find that you can't install the mounting nuts because the underside of the sink is in the way!
Turn the countertop over. Measure the shortest distance from the back of the integral sink to the rear of the countertop. Flip the countertop back and transfer this measurement to the front of the sink. If the countertop has a backsplash be sure to subtract its thickness or you will locate the holes too close the sink hole. Locate the center of the faucet holes at least 1" back from this mark.
(NOTE: If your countertop is not flat, be sure that the entire faucet is located on a flat area. Some of the "styled" countertops only give a little room for error.)
Now you should center the mark you made by measuring the width of the countertop and dividing by 2.
Depending on the size of the faucet, the "center-to-center" measurement for the two outside "inlet" holes may be the old industry standard 4" or more. Measure your faucet and transfer this dimension to your countertop. Most bathroom sinks require three holes... two for the supply lines and a center one for the pop-up control rod. The center hole should be exactly between the outer two. Double check your measurements by placing the faucet over the marks... you can never be too careful!
If your sink needs a fourth hole... for a soap dispenser, for example... don't displace the faucet to one side unless absolutely necessary. Instead drill for the faucet first, temporarily install it in the countertop and then position the soap dispenser... being sure to allow clearance underneath for the soap bottle under the sink.
First things first! Solid surface can only be drilled with a router, hole saw or spiral drill bit. Do not use an auger-style bit or sabre saw... it will microfracture the material which can lead to widespread cracking!
The drilling is done in two steps. First, drill a locator hole through the countertop at each of the three marks. This hole should be just slightly smaller than the size of the pilot bit of your hole saw. Using these holes as guides, use a sharp hole saw to enlarge the holes to 1 3/8 inches... the standard size. Under no circumstances drill a hole larger than this. The smallest acceptable hole is 1 1/4", though the pop-up assembly ( the mechanism that moves the stopper up and down) may bind with some faucets, requiring you to ream out the center faucet hole slightly.
I can't emphasize enough to use a very sharp hole saw. If you don't, a few things can happen. The worst is that the hole saw will bind while drilling, skip out of the hole and destroy your entire day along with the countertop. A dull blade tends to generate lotsa heat, which can cause the plastic resin in the Corian® to melt or burn onto the hole saw, making it duller and increasing the heat, etc., etc. and so on. Furthermore, the excessive pressure needed to coax a dull drill could cause the Corian® to break or crack. If you are not sure of the sharpness of that ol' hole saw you have laying in your workshop, go buy a new one!
Keep the drill speed moderately low... just apply enough power to keep the holes saw cutting at an even rate. If the saw seems to be bogging down, increase the speed a little. Don't exert too much downward force... let the sharp hole saw do the work. Don't forget to remove the scrap Corian® from the hole saw before making the next hole!
Sand the edges of the holes when done... Proper solid surface installation requires all holes to be sanded... as countertop pro Joseph Corlett of Corlett Construction advises... to remove the "meanness" off the faucet holes to prevent possible fractures around them.
Speaking of scrap, one of my customers made a great suggestion… keep the cut-out scraps to help you color-match paints or wallpaper!!
(Our thanks to Dupont for the use of the topmost photo of a Corian® bathroom sink with integral sink, Copyright© 1995, 1996, 1997, 1998, 1999, 2000 E. I. du Pont de Nemours and Company, 1007 Market Street, Wilmington, Delaware 19898, USA All Rights Reserved)
Written by Jerry Alonzy
Jerry Alonzy, a.k.a. the Natural Handyman, has been an active handyman for over 30 years with experience in most areas of home repair and renovation.
As a do-it-yourself author and web developer since 1995, he has been featured in USA Today, the Today Show and on radio shows, magazines, newspapers and websites. His material appears widely on the web, but primarily on his website... The Natural Handyman. You can also find him on Google+.