Making Laminate Countertops
A laminate countertop consists of a thin sheet of plastic laminate glued down over a 3/4" plywood or particleboard core called a substrate. The whole process isn't too hard to fabricate.
Cut the substrate material to fit over the cabinet run.
Create a build-up on the bottom by screwing 4" wide strips of the same substrate material around the perimeter and wherever the top hits the cabinet framing.
Glue the laminate to the edges and to the top with contact cement.
Typically, you cut each piece of laminate a little big, glue them on one at a time and trim each one flush to the substrate with a router and a flush-cutting laminate bit before gluing on the next piece.
Trimming the laminate on the top flush with the front edge leaves a sharp 90 degree angle, but professionals usually file that off a bit at a 45 degree angle to leave a beveled edge that's less likely to pry loose.
TIP: It's easiest to do all that before attaching the substrate to the cabinets so you can leave a little of that overhang for scribing during installation.
There are now special edgings you can buy to give your laminate top a solid wood edge in a variety of shapes and styles. Most of these have a spline along the back, and you route a matching groove into your build-up, run a bead of glue in there and pound the edging so the spline nestles firmly in the groove.
Installing Laminate Countertops
If you're installing a countertop first and applying a separate backsplash later, the backsplash will cover any gaps between the wall and the top.
So you can simply push the countertop in place and secure it by driving screws up through the cabinet frame (special corner blocks are often provided for this).
But if you're not planning a backsplash or you've applied one to the top prior to installation as described in the previous step, then scribe the back to accommodate any variations or waves in the wall and eliminate gaps at the back.
Push the top into position.
Set a compass to about a 1/4" or so and run the pointer along the wall scribing a line on the laminate overhang.
Trim the laminate with a belt sander or file back to the scribe line.
Reposition the countertop against the wall and secure it with screws driven up through the cabinet framing.
Making A Laminate Backsplash
If you build your own laminate countertop, you can attach a backsplash to it pretty easily once the laminate's glued down to the top.
Rip a piece of 3/4" substrate material down to a width of 3 1/2" or 4" (depending on how high you want the backsplash) and cut it to the same length as the top.
Rip a piece of 1/4" stock to a width of 1" and cut that to the same length as the top and backsplash to serve as a scribing strip.
Glue and screw the scribing strip to the top of the backsplash flush with its front, leaving about a 1/4" of the strip hanging over the back.
Apply strips of laminate to the front, top and ends of the backsplash one at a time using contact cement and trim each one flush with the edges.
Clamp the backsplash in place at the back of the countertop, pre-drill pilot holes from the bottom of the countertop up into backsplash, unclamp it, apply carpenter's glue, reclamp it and drive 2 1/2" drywall screws up through the pilot holes to secure it.
Setting "Post-Form" Laminate Countertops
"Post-form" laminate countertops are prefabricated pieces that come in a variety of lengths complete with rolled front edges and backsplashes. You just cut them to the exact length you need, scribe the backsplash to the wall and screw them to the cabinet framing.
The easiest way to cut them is to turn them upside down, measure the length off on both the back edge and the front edge, mark a cutting line with a straight edge and cut it with a jig saw, which can negotiate the uneven cutting surface along the buildup and the backsplash better than a circular saw.
TIP: Clamp a straight-edge along the cutting line, offset far enough for the jigsaw's table, to help you cut a perfectly straight line.
Each cut leaves a rough edge. But, you can buy kits with pre-cut "iron-on" pieces of laminate that you apply to the cut edge and seal with heat from an iron. That dresses up the ends where they'll be visible.
If you need to fit the countertop over a corner, you can buy lengths of post-form countertops with pre-mitered ends that glue together over the corner and tighten from below with drawbolts in special pre-drilled holes.