10″ mattress daybed plans

Parts

Cut list

Kerf 1/8″ included. Every cut runs edge to edge.

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)
• Two bar clamps at least 36″ long
• A helper for lifting the sides
• Sander, 120 and 180 grit

Underlined words have a short explanation: hover or tap them. All of them are on the glossary page.

1. 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.

2. 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.

3. 3Build the two side frames

   Lay a front post (A) and a back post (B) on the floor on their narrow edges, 32″ apart inside, floor ends lined up against a straight board. These are the legs and the arm posts in one.

   Lay the side rail (C) across them with its front end flush with the front of the front post, its back end flush with the back of the back post, and its bottom edge 7″ above the floor ends.

   Spread glue where each rail crosses a post. Drive 4 screws, 3″, at each crossing in a square pattern 1″ in from the edges. Drill 1/8″ pilot holes first.

   Lay the arm rail (D) across the posts the same way, with its top edge flush with the top of the front post (28 1/2″ from the floor). Glue and screw it the same way.

   Build the second side as a mirror image: the rails go on the inside face, so on a finished piece both sets of rails face each other.

   • Tip A screw in each corner of a square is far stronger than four in a row: it stops the rail from pivoting.
   • Tip Pick the straightest 2×4s for the posts; sight down each one at the store.

   ✓ Measure each frame corner to corner both ways; the diagonals match within 1/8″. The two frames are mirror images when you stand them face to face.

4. 4Line the arms with plywood

   Each arm panel (E) covers the inside of a side frame. Hold it against the inside faces of the rails, bottom flush with the bottom of the side rail, 1 1/2″ back from the front and the back ends (the front and back rails butt into those gaps).

   Glue and drive 1 5/8″ screws through the panel into both rails every 6″.

   The panel turns the open frame into a stiff box, so the arm cannot rack when someone leans on it, and it is the wall the cushions sit against.

   ✓ Push the top of the back post sideways: the side frame does not change shape.

5. 5Join the sides with the front and back rails

   Stand the side frames up, panels facing in, 77 3/8″ apart between the side rails. A helper holding one side makes this much easier.

   Fit a front rail (G) between the side rails at the front, flush with their fronts and bottoms. Glue the end of the rail, clamp it in place and drive 2 screws, 3″, through the side rail into its end (pilot holes first, 1″ and 4″ from the top edge). Then screw 2 L-brackets into the inside corner, one high and one low.

   Fit the back rail the same way at the back.

   Measure the diagonals across the frame (front left post to back right post, and the other way). Push the long corner until they match, then let it sit.

   ✓ The frame is 83 3/8″ wide, the diagonals match within 1/8″, and all four posts touch the floor.

   STOP. Lift the frame with a helper from here on; it is heavy and awkward.

6. 6Lay the slats

   Lay the 14 slats (H) flat across the front and back rails, front to back, 2 1/16″ apart, the first and last tight against the arm panels.

   Drill two pilot holes at each end of every slat over the rail, countersink and drive 2 1/2″ screws.

   Gaps let the mattress breathe so it doesn't trap moisture and mildew underneath.

   • Tip Cut a spacer block the width of the gap and use it for every slat.
   • Tip Lay each slat with the arcs of the growth rings on its end pointing down, so it crowns up slightly under weight.

   ✓ Every gap is 3″ or less and the slat tops are level with each other.

7. 7Build the back

   Fit the top back rail (I) between the back posts, its top front corner level with their tops and its back face flush with their backs. Glue the ends and drive 2 screws, 3″, through each post into the rail end (pilot holes first), plus an L-bracket in each inside corner.

   Lay the frame on its front on a blanket. Fit the back panel (J) over the back, edges flush with the outsides and the top. Glue and drive 1 5/8″ screws every 8″ into the posts, rails and top rail.

   ✓ Stand it up and push the top of the back from the front: it doesn't lean or creak.

8. 8Cap the arms

   Round over every top edge of the arm caps (F) with 120-grit paper or a router: arms get touched more than anything else.

   Lay a cap on each arm, back end tight against the back post, outer edge flush with the outside of the post. It overhangs the arm panel on the inside by about 1 13/16″.

   Drill and drive 3 screws, 3″, down into the front post and 3 into the arm rail. Fill the screw holes with wood filler and sand flush.

   ✓ Press down hard on the front end of each arm: no movement.

9. 9Add the mattress and test

   Lay a twin mattress (38″ × 75″, 6–10″ thick) on the slats. It fits between the arm panels with about 1/2″ to spare at each end.

   Before anyone uses the daybed, sit down slowly, then rock gently side to side and front to back. Nothing should creak, shift or rack. If a joint moves, add glue and a screw there before going further.

   Then lie down and roll from side to side.

   ✓ No creaks, nothing moves at the corners, and the slats don't bow under one person kneeling in the middle.

10. 10Finish

    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.