Find the largest gap between the countertop and wall.

Measure the Gap

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited View original photo.

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Step 1

Installing a countertop is reasonably straightforward. However, joining two lengths of material to take a countertop around a corner requires more care, since the joint needs to be perfect to create a continuous, flat finish. The best joints can be achieved if you use the right techniques, and make good use of factory-cut straight edges. Joining a countertop material with square edges is easier than if the front edge has been finished with a curved profile.

Step 2

Scribe to Fit

Any deviations in the wall surface will cause gaps along the back edge of the countertop. In these situations, the best finish is achieved by scribing the countertop to fit the wall. Consider that you will lose some countertop depth, so if the gaps are large, buy a wider countertop and trim it as described below.

Position the countertop with the back edge touching the wall and the front edge overhanging the cabinets by the same distance along the run (Image 1).

Measure the largest gap between the countertop and the wall and cut a small scribing block of wood the same width (Image 2).

Hold a pencil at one side of the block as you run the other end along the wall (Image 3). This will provide a guide line for trimming.

Use a jigsaw to cut along the line (Image 4). You may need to use a sander or plane where a small amount of material needs to be removed.

Reposition the countertop and check that you have a good fit between wall and countertop, and a consistent overhang at the front (Image 5).

Step 3

Cut to Length

For a straight run, the countertop needs to be cut to the right length, including an overhang of about 1 inch (25 mm) at each end. Handsaws or power saws can be used. Make sure you use an appropriate blade. For a laminate countertop, place masking tape over the cutting line to help prevent any splintering of the laminate surface.

Draw a pencil line across the countertop where you want to cut it, and cover the line with masking tape (Image 1).

Clamp a straight edge to the countertop along the guide line (a metal ruler is ideal). Using a utility knife, score down the line through the masking tape (Image 2).

Carefully saw through the scored line using a panel saw (Image 3). Make sure the countertop is well supported on both sides of the cut.

Remove the remaining masking tape. Use a block plane to smooth the cut end of the countertop (Image 4).

Step 4

Trim the Width

If you have a wider counter than you need, you can trim it at the same time as scribing it to fit. With the counter positioned on top of the base units, work out the width of material that needs to be removed to leave you with your desired overhang. Subtract the width of the largest gap at the back of the countertop from the trimming amount and cut a scribing block of this length. Use the block in the same way described above.

Deciding on what size of overhang is required at the front of the units is a matter of personal taste. Some people prefer a finish fairly flush with the drawer fronts, other people prefer a larger overhang. The standard overhang is 1 1/2 inches (38 mm). Cut through the countertop using the method shown left.

Step 5

Turning a Corner

If you want your countertop to turn a corner, you will need to join two lengths. Options for joining are limited by the material the countertop is made from, and whether its profile is square or rounded. Once a joint has been cut, it is essential that it is held tightly in position. Mending plates can be installed across the joint on the underside of the counter, or a biscuit joiner will create an exceptionally strong joint.

Step 6

Round-Edged Countertops

If your counter is supplied with a curved finished edge, it is not possible to create a simple right-angled butt joint. The best option is to use a joining strip, or a countertop jig. Making a mitered joint is possible, but will be hard to cut accurately unless you use a jig.

Step 7

Countertop Joint Kits

Some manufacturers provide joint kits. Basically, these are colored fillers used to cover a less than adequate miter or butt joint. Some are epoxy-based, so you should remove any excess before it has a chance to dry.

Step 8

Using a Jig

Professional kitchen installers use countertop jigs for accuracy. These specially designed tools are relatively expensive, although often they can be rented. The jig provides a template for a router to cut against. With practice, it produces very accurate cuts for each side of the joint required, and guides for notched cuts to fit connector bolts to hold the joint together.

Step 9

 Apply weight to the countertop as you fasten the screws.

Secure the Countertop

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited View original photo.

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Joining Square-Edged Countertops

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Square edges mean that two sections of countertop can be easily and neatly butt-joined without the need for a countertop jig. Once the countertop is fixed in place, the front edge may then be finished using a router.

Cut the countertop lengths to size and, if necessary, scribe. Apply wood glue along one of the joining edges.

Push the countertop together and secure the joint using a mending plate and screws. You may need to drill pilot holes for the screws, and apply weight to the countertop as you fasten the screws. Wipe away excess glue. For an even stronger joint, use two or even three mending plates.

Step 10

Joining Solid Surfaces

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Cut a joining strip to the width of the countertop, then secure it using selant and screws. Apply sealant along the edge of the other countertop (Image 1).

Butt the sections together (Image 2), and use a cloth to remove any excess sealant.

Step 11

Securing a Countertop

Once a countertop has been cut to size, it should be secured in place using screws inserted through the countertop brackets that are attached to the units and rail. You will need someone to apply weight to the back of the units while you attach them.

Clamp the countertop to the cabinets along their front edge. Insert screws through the rail into the underside of the countertop (Image 1).

Apply weight from above while you secure the back of the countertop using mending brackets (Image 2).

Step 12

Finishing the Edges

Laminate countertops
These often have unfinished edges that require covering with laminate strips supplied by the manufacturer. The strips can sometimes be ironed on, but others will need contact adhesive. Once the strip is fastened in place and any adhesive is dry, you can trim the edges flush using a utility knife.

Solid surface countertops
Sawn edges of some types of solid surface can be sanded smooth. Always check manufacturer's guidelines.

Solid wood countertops
These are best sanded smooth, then stain-protected using the oil recommended by the manufacturer. Paint on several coats of oil, removing any excess with a dry cloth. Extra oil may be required at intervals to maintain the finish.

Concrete countertops
After installation, seal the exposed surfaces with a sealing product. The sealer prevents the surface from absorbing food stains and odors, and it makes it easier to clean. When dry, buff out the surface using an abrasive pad. Then apply a coat of acrylic clear finish. To achieve a high-gloss finish, buff the surface.

Stone countertops
You can always seal your stone countertops, but keep in mind that a sealer does not make the stone unstainable. The sealer’s main job is to fill the pores in the stone and make the staining process slower, so you have more time to clean a spill before a stain sets in. Marble and granite surfaces should be sealed at least once every year.