Drag an orange dot to resize; a dashed line shows when it snaps to a common size. Click a dot, then use the arrow keys to nudge 1/8″ (hold Shift for 1″). Every size can also be typed in the panel.
Checks
- The tray bottom passes the sag check.
- Inserts only: nothing here touches the pipes, drain, disposal or shutoff valves. Keep the valves reachable with the trays in place.
- Only the left side has room for a tray.
Shopping list
| Qty | Item | Est. |
|---|---|---|
| 1 | 1×12 pine board, 6′ (board) | $21.60 |
| 1 | 1/2″ birch plywood, 4×8 sheet (sheet) | $52.00 |
| 1 | 18″ full-extension ball-bearing drawer slides, 100 lb (pair) | $14.50 |
| 1 | 5/8″ pan-head screws (slides, hinges) (box of 100) | $6.00 |
| 1 | 1 5/8″ wood screws (box of 100) | $9.00 |
| 1 | 1″ brad nails (box of 1000) | $6.00 |
| 1 | Wood glue (bottle) | $5.00 |
| 1 | Double-sided carpet tape (roll) | $7.00 |
| 1 | Waterproof under-sink cabinet mat, cut to fit (each) | $20.00 |
About $141 · rough estimates, check the store
Parts
| Part | Qty | Length | Width | Material | |
|---|---|---|---|---|---|
| A | Base | 1 | 20 3/4″ | 9 1/4″ | 1/2″ birch plywood |
| B | Runner Rip to 6″ wide. | 2 | 20 3/4″ | 6″ | 1×12 pine board |
| C | Tray side | 2 | 18″ | 5″ | 1/2″ birch plywood |
| D | Tray front and back | 2 | 5 13/16″ | 5″ | 1/2″ birch plywood |
| E | Tray bottom | 1 | 18″ | 6 3/4″ | 1/2″ birch plywood |
Cut list
1/2″ birch plywood, sheet 1 of 1
1×12 pine board, 72″ → B 20 3/4″ · B 20 3/4″
Kerf 1/8″ included. Every cut runs edge to edge.
Have the store cut it
Most home centers rip sheets on their panel saw. Show them this; do the short crosscuts at home.
- 1/2″ birch plywood: rip into strips 9 1/4″, keep the rest.
Steps
- Tape measure
- Speed square
- Pencil
- Drill/driver
- Clamps
- Safety glasses
- Hearing protection
- Dust mask
- Circular saw and a straight edge (or have the store cut the sheets)
- Hammer
- Table saw or track saw for ripping
- Sander, 120 and 180 grit
1Before you start
Read every step once, start to finish, before you buy or cut anything. Each step names the parts it uses by letter; the parts list gives their sizes.
Set up somewhere flat with good light. A pair of sawhorses with a sheet of plywood on top makes a fine work table.
Wear safety glasses whenever a tool is running, hearing protection for saws, and a dust mask for sanding and for cutting treated wood or sheet goods. Tie back long hair and loose sleeves. Keep children and pets out of the work area.
- Tip At the store, pick straight boards: hold each one up to your eye and look down its length. Skip boards that bow, twist or have big knots near the ends.
- Tip Measure twice, cut once. Most mistakes are a misread tape, not a bad cut.
2Cut and label the parts
Cut every part on the cut list. Cut the longest parts first: if one goes wrong, it can still become a shorter part.
To mark a cut, hook your tape on the end of the board, make a small V with its point exactly at the measurement, and draw a square line through the point with a speed square. Put an X on the waste side.
Cut on the waste side of the line, so the blade's kerf (about 1/8″) comes out of the scrap, not your part. Cut sheets with the good face down when using a circular saw: the blade splinters the top face.
Write each part's letter in pencil on a face that won't show, and stack the parts by letter.
Sand the faces before assembly while they're flat and easy to reach: 120 grit, then 180.
✓ Lay the parts out and count them against the parts list. Measure a few: if one is off by more than 1/16″, recut it now.
STOP. Let the saw reach full speed before it touches the wood, keep both hands clear of the blade's path, and never reach under a board you're cutting. Support long boards on both sides of the cut so the blade doesn't pinch.3Empty the cabinet and check for leaks
Take everything out. Dry the floor of the cabinet and lay a paper towel under each pipe joint, the shutoff valves and the disposal if you have one.
Run the hot and cold water for a minute each, fill and drain the sink, and run the dishwasher drain if it ties in here. Check the paper towels.
✓ Every paper towel is dry after an hour.
STOP. If anything drips or the cabinet floor is soft or swollen, stop and fix the leak (or call a plumber) first. This plan does not touch any pipe, valve or drain.4Measure around the pipes
Measure inside the cabinet: wall to wall at the floor, and from the back wall to the back of the closed door.
Measure the narrowest width of the door opening: between the face-frame edges, or between the open hinges, whichever is narrower. The trays have to slide out through it.
From the left inside wall, measure to the left edge of the left-most pipe, valve, trap or disposal, and to the right edge of the right-most one. Measure low, near the floor, where the trays will be.
With your numbers, the left tray carrier is 9 1/4″ wide, 1 3/4″ from the left wall. Each stays 1″ away from the pipes.
✓ Every tray position is inside the door opening and at least 1″ from every pipe, and the shutoff valves can still be reached by hand.
5Build the tray boxes
Glue and brad the front and back of each tray between its two sides, ends flush: 3 brads per corner.
Square each box, then glue and brad the bottom on underneath, every 4″. The bottom holds the box square.
Drill a 1″ finger hole in the middle of each tray front, 1″ down from the top edge.
- Tip Seal the trays inside and out with water-based polyurethane: under a sink, things get wet.
✓ The diagonals of each box match within 1/16″.
6Build the carriers
Each carrier is a base with a runner standing on each long edge. Stand two runners on edge on a base, flush with its long edges and both ends.
Glue and drive 4 screws, 1 5/8″, up through the base into each runner.
✓ The runners are square to the base and parallel: the gap between them is the same at both ends.
7Fit the slides
Separate each 18″ slide into its two halves (there is a small lever on the inner part).
Screw the outer halves to the inside faces of the runners, their bottom edge 1″ above the base and flush with the front ends, 3 screws each. Screw the inner halves to the tray sides, flush with the bottom edge of the side and the front.
Slide each tray into its carrier until it clicks.
✓ Each tray runs all the way in and out without rubbing, and stops level.
8Set the carriers in the cabinet
Cut the waterproof mat to the cabinet floor with scissors and lay it down.
Put two strips of carpet tape under each base and set the carriers in place: left one 1 3/4″ from the left wall, 1/4″ from the back wall.
Press down hard. Pull each tray out fully to check it clears the door, the hinges and the pipes.
✓ Both trays pull out past the face of the cabinet with the doors fully open, and nothing touches a pipe.
STOP. Don't screw into the cabinet floor or walls near the pipes. If the trays slide around, use more tape.9Finish
Ease every sharp edge and corner with 120-grit sandpaper so nobody gets a splinter.
Sand all over with 180 grit, always along the grain (the direction the wood fibres run). Scratches across the grain show through stain.
Wipe off the dust with a barely damp rag and let it dry.
Paint, stain or a clear coat (water-based polyurethane is the easiest). Apply thin coats with the grain, let each dry fully, and sand lightly with 220 grit between coats.
Let it dry for the time on the can before using it.
- Tip Try your finish on a scrap of the same wood first: stain looks different on every board.
Conceptual layout, material estimate and assembly guide from the sizes you entered. Not engineering, not a building plan, not stamped or approved. Confirm measurements on site; follow local codes and product instructions; anchor tall pieces before use. Using this plan means you accept the Terms of Use.