3. Repeat this process for the second top piece. Use the first miter cut to mark the second miter cut. This allows you to keep the joint as tight as possible.
4. Use a biscuit joiner to carve out matching grooves on the miter cut of each piece. This helps make the joint stronger, while keeping it level while joining the two pieces. Add wood biscuits (with wood glue) and clamp the two pieces together in as many ways as possible. Let this cure for roughly 30 minutes.
5. Add a wood brace across the joint on the underside of the countertop. This will help the two pieces from spreading down the road.
6. Use wood filler to fill any gaps in the miter joint. Then sand any excess wood filler after it cures.
8. Measure and cut the ‘waterfall’ end panels on each side of the countertop. Check to see how plumb the walls are before assuming the pieces will be cut perfectly square. Use a brad nailer to attach the waterfall end panels. I only joined the side panels to the top panels. There are no nails into the actual KALLAX unit anywhere.
9. Use a table saw to cut 1 1/4″ wide strips out of oak plywood. These will go inside the top and edge panels of the countertop. Use a miter saw to cut the inner edge pieces to length. I mitered these corners as well to match the overall design.
10. Clamp (to hold) and attach the edge pieces with a brad nailer. You only need a few nails to fix them in place.
11a. Stain the entire countertop in the color of your choice. I used walnut for this build.
11b. Seal the unit with polyurethane and let it cure for 3-4 hours. Give it a light sand with 220 grit sandpaper.
12. Repeat step 11b to get a nice smooth and solid finish. And your KALLAX home office furniture is done!
Total cost for the wood and knobs is roughly $200 dollars. We received the KALLAX units for free. Cost for cabinet doors and drawers was around $140 dollars. This is all in Canadian, by the way.
The hardest part of the whole hack is getting the miter joint on the top of the countertop as tight as possible. As of right now, I wouldn’t change anything, but that may change the longer we use the unit.