Q: What is the quickest and most accurate way to template a countertop in an old house with wavy walls and odd projections?

A: Roe Osborn, senior editor at JLC, and author of Finishing a House, responds: I spent quite a few years working as a joiner in a boatyard. For that job, most of the templating we were asked to do involved curves and irregular surfaces. The tool we reached for most often was called a “spiling block.”

Borrowed from its duties in the boat-building industry, a spiling block can be useful for making templates. The block is basically a rectangle with one corner clipped at 45 degrees. The clipped corner helps you index the block on the template material. The block itself can be any size, but it doesn't need to be very big. The one shown here, made from a scrap of 1/4-inch-thick plastic sheeting, is about 2 inches by 3 inches, a size that fits conveniently in a tool box or tool belt.
Borrowed from its duties in the boat-building industry, a spiling block can be useful for making templates. The block is basically a rectangle with one corner clipped at 45 degrees. The clipped corner helps you index the block on the template material. The block itself can be any size, but it doesn't need to be very big. The one shown here, made from a scrap of 1/4-inch-thick plastic sheeting, is about 2 inches by 3 inches, a size that fits conveniently in a tool box or tool belt.

A spiling block is typically a small rectangle made of some sort of hard material. I still use a spiling block that I made back then from a 2x3-inch scrap of 1/4-inch-thick plastic sheeting (see photo), but I’ve made others from thin plywood or hard laminate. (The exact size is not important, but the block I made fits nicely in my toolbox and tool bags). To make a spiling block, cut a rectangle with square sides. Then cut an indexing corner at a 45-degree angle.

To show the process, this illustration sets up the familiar situation of templating a countertop to a wavy wall—a fairly typical challenge in older homes. We added a projection—also typical—and made the adjacent wall straight to help demonstrate the process.
Tim Healey To show the process, this illustration sets up the familiar situation of templating a countertop to a wavy wall—a fairly typical challenge in older homes. We added a projection—also typical—and made the adjacent wall straight to help demonstrate the process.

For the template itself, I cut strips of 1/4-inch plywood 3 to 4 inches wide. I start with a strip along the straightest wall and screw it to a strip that runs along the wall with the irregularities. Be sure that the template strips are well attached and stable at the corner (some folks use hot glue, 5-minute epoxy, or diagonal strips in addition to screws). Continue building the template until you have strips on all four sides. Secure the template to the cabinet or structure below that will be supporting the countertop.

First build a rough template out of strips made from 1/4-inch plywood. Set one edge against the straight wall, and hold the other edge off the wavy wall. Secure the corners of the template and attach the template to the cabinets to keep it from moving.Starting at one end, place the spiling block against the wall irregularity and trace the end of the block onto the plywood strip. Now move the block to a different position and trace the block again. At the projection, use the spiling block to register all three sides.
Tim Healey First build a rough template out of strips made from 1/4-inch plywood. Set one edge against the straight wall, and hold the other edge off the wavy wall. Secure the corners of the template and attach the template to the cabinets to keep it from moving.
Starting at one end, place the spiling block against the wall irregularity and trace the end of the block onto the plywood strip. Now move the block to a different position and trace the block again. At the projection, use the spiling block to register all three sides.

Slide the square corner of the spiling block into the wall corner or at the end of the wall, and hold the block down firmly against the template strip. Using a sharp pencil, follow the entire end of the block that has the 45-degree index cut, tracing it onto the template strip (as shown in the illustration, below). Now work your way along the irregular surface, sliding the block against the wall and tracing the block onto the strip. Repeat this process at several places along the wall, particularly where the surface changes direction, flattens out, or goes from convex to concave. Write labels or make notes on the template to indicate key locations, such as a corner or a place where there is a change of direction.

Continue sliding the spiling block along the irregular wall surface, tracing in as many places as you deem necessary. Add labels that will help guide you when transferring the shape to the countertop material. We used a "P" to label the three sides of the projection, a "B" to label the farthest extent of the wall bulge, and a "C" to denote the corner of the room. It may also be helpful to trace the block along the straight wall and label that as well.
Tim Healey Continue sliding the spiling block along the irregular wall surface, tracing in as many places as you deem necessary. Add labels that will help guide you when transferring the shape to the countertop material. We used a "P" to label the three sides of the projection, a "B" to label the farthest extent of the wall bulge, and a "C" to denote the corner of the room. It may also be helpful to trace the block along the straight wall and label that as well.

To transfer the location of a projection such as a plumbing or electrical chase onto the template strip, use the spiling block to record all of the sides, again labeling each trace that you do. If the block can’t reach all the way to a certain point (such as an acute angled corner), trace the block while holding it against the wall or surface with the long point. Then measure from the traced corner point on the template strip to the long point of the corner and write that measurement on the template. When you transfer the template to the countertop material, simply extend that line to the distance you wrote down.

When you’ve finished templating the entire irregular surface and have labeled any anomalous places, carefully remove the template and place it on the countertop material. If there is a finished straight edge on the material, align the straight edge of the template along that side.

When you have finished templating the irregular wall, carefully remove the template from the cabinets and place it on the countertop material. Align the straight side of the template with a straight edge of the countertop material. Place the spiling block on the template at the traced shape at the corner, and align the free corner of the spiling block with the corner of the countertop material. Now continue down the template, placing the block on each  traced shape and marking the other end on the countertop material. When you have transferred all of the spiling block locations, remove the template and connect the marks. Most often the waviness will be gradual enough to connect the spiling marks with straight lines. Otherwise a flexible batten can be used for more radical shapes.
Tim Healey When you have finished templating the irregular wall, carefully remove the template from the cabinets and place it on the countertop material. Align the straight side of the template with a straight edge of the countertop material. Place the spiling block on the template at the traced shape at the corner, and align the free corner of the spiling block with the corner of the countertop material. Now continue down the template, placing the block on each traced shape and marking the other end on the countertop material. When you have transferred all of the spiling block locations, remove the template and connect the marks. Most often the waviness will be gradual enough to connect the spiling marks with straight lines. Otherwise a flexible batten can be used for more radical shapes.

Firmly but gently clamp the template to the material, taking care not to distort the template. Set the spiling block back on the template, and align it with every trace that you made (as shown in the illustration). At each location, trace the other end of the block onto the countertop material, continuing the process until you have transferred every position that you marked on the template.

Now connect the marks on the countertop material. If the curve is subtle, you may be able to connect them with straight lines. If the curve is more pronounced, use a flexible batten to connect the marks for a fair and even curve. When the line is complete, you’re ready to cut the irregular edge of the material to the line for an exact fit.