Choosing a farmhouse sink – also called apron front – is both a fashion statement and the ultimate in functionality. Most of the time, installation involves new cabinetry, but now … Kohler offers the Whitehaven, the first retrofit farmhouse sink on the market that installs with your existing cabinets.
Here’s how it works:
First, you’ll need a few tools:
- Painter’s tape
- Tape measure
- Plumber’s putty
- Wood screws
- Adjustable wrench
- Silicone sealant
- Construction adhesive
- Safety glasses
Out with the old …
Next, remove any accessories in your sink, like grids, sponge holders, etc. Now turn off the water supply and run the faucet to remove any residual water.
If you have a dishwasher and/or garbage disposal connected, disconnect the power to both before you loosen and remove the water supply lines to the faucet. You’ll also need to disconnect the supply hose from the air gap to the drain if you have one.
Unscrew the slip nuts on the p-trap from the garbage disposal and waste pipe as well as the other sink drain, if applicable, and remove them. Have a bucket handy in case of any water remaining in the p-trap.
Remove the basket strainer by unscrewing the lock nut of the strainer and removing the pressure cup and rubber washer. Then lift out the basket strainer and set aside.
If you have a garbage disposal, insert a screw driver in the loop of the mounting ring and turn clockwise to loosen the disposer and remove it. You can use the same screwdriver to unhook the snap ring holding the mounting ring to the sink flange and remove that as well.
Don’t forget to disconnect the air gap and remove the hose.
Next, loosen the screws on the faucet mounting nut, and turn it counter-clockwise to remove. You should be able to pull the faucet up and out of the sink.
If you are replacing a drop-in sink, you’ll need to check for the brackets holding the sink to the counter top. Loosen the nuts and turn the bracket to remove.
Grip the sink form the drain holes, and lift the sink off the counter. It may take some effort to break the glue seal under the sink.
To remove the counter top, remove any screws holding it to the cabinets as well as any screws holding the counter top to the wall.
If you have a dishwasher, remove the screws to the dishwasher brackets as well.
You may need a rubber mallet to break any seals of the counter top to the cabinets and wall. Lifting the counter top and moving it may require assistance.
Remove any supports or risers on the cabinets because they will interfere with the granite counter top being installed after the Whitehaven sink goes in.
Next remove the cabinet doors and false fronts on the sink cabinet. To protect the finish of the cabinet when cutting, apply painters tape to the cabinet where each cut will be made. Use this surface when marking the measurements
… and in with the new
For your first measurement, make sure you are measuring from the outside of the cabinet wall, not the front of the cabinet. Measure 7/8 of an inch or 22 millimeters from the outside wall and mark the tape. A square is helpful for marking straight lines.
Do the same for the opposite side.
Cut along the marked line until your cut extends slightly below the front rail of the cabinet. Follow along the bottom edge of the rail and cut towards the outside of the cabinet until you intersect with your first cut.
Repeat this for the other side.
If your cabinet has a center support, you’ll need to cut along the bottom edge of the opening to remove and discard the rail. If your cut is uneven you may want to sand it flush.
Please note: In order for the new counter top to go in correctly, the top of the sink must not extend above the top of the cabinet. The top surface of the sink should sit approximately 1/16 of an inch or 2mm below the top edge of the cabinet.
Also, be sure to use appropriate fasteners and material for your support framing that will support up to 300 pounds or 136 kilograms.
Next measure 5/8 of an inch or 16 millimeters from the top of the cabinet and mark.
With a level, draw a line across the cabinet with your marks. Measure the length of the cabinet, then mark and cut your top rail support board.
Apply construction adhesive to the board, and attach it to the cabinet lining the top of the board with your mark.
Check the board is level, and use clamps to hold the support in position. Double check that your alignment and measurements are correct.
The wood screws you’ll need must be long enough to secure the support framing but short enough not to extend through the walls of adjacent cabinets. Secure the support with screws.
Repeat the process for the other side.
Next, measure and cut for two vertical supports on each side. Apply adhesive to your support boards and secure them with screws.
With help, lower the sink onto the supports and verify the sink is fully supported. Push the sink in until the apron is snug to the front of the cabinet, and verify the sink is level.
Installing new countertops
Measure the opening for your sink cutout for the counter top, and install the new counter top.
With help, shim the sink on the supports to make it level with the underside of the counter top. Then, apply a bead if silicon around the sink where it meets the counter top and wipe off any excess.
You’ll need a granite hole saw to cut for your faucet and air gap holes. Be sure you mark clearly and accurately where those cuts will be made,then install and secure any back splashes.
The finishing touches
To install the sink strainers, first roll out a bead of plumbers putty to about 3/4 of an inch or 7 millimeters thick. Wrap it around underneath the flange and remove any excess.
Press to spread and seat it around the flange. Place the strainer basket in to the sink hole and press down firmly. Under the sink, install the rubber washer, paper washer, pressure cup and lock nut and tighten down.
Repeat the same plumbers putty application for the opposite strainer or garbage disposal flange if applicable.
Reconnect the garbage disposal mounting bracket and snap ring, then wipe off any excess plumbers putty around the strainer baskets.
Insert the air gap through the counter and tighten down the top housing.
Reconnect the drain pipe tailpiece and the air gap hose and tighten down before connecting the drain connections and hand tightening them.
Don’t forget to reconnect the garbage disposal and drain connections.
Now you can install the faucet and reconnect the water lines. Check to make sure the water runs and there are no leaks.
Once complete you should enjoy your new Kohler Whitehaven sink for years to come.