Turn Basic Bookshelves into Arched Built-Ins with Plywood
The short version
Monica from The Weekender turns three pre-built Lowe's bookshelves, each 3 ft wide and 6 ft tall, into arched built-ins for a homeowner named Tim. The project covers measuring, a cut list, tracing arches with a scrap-wood pivot, framing with 2x4s and 1x8s, attaching plywood arch faces, trim, and green paint.
Full written account
Three basic bookshelves from Lowe's, each 3 ft wide and 6 ft tall, become the foundation for arched built-ins in a project led by Monica from The Weekender with homeowner Tim, from the family fun room episode. The shelves are encased to look built in, with arches across the top.
Measuring the space
The first step is to centre the middle bookshelf on the centre of the wall and work outward. Four measurements are needed: the total width of the space, which sets the spacing between bookshelves; the height from the top of the bookshelves to the ceiling (here a soffit); the width of the bookshelves, which sets the arch size; and the depth of the bookshelves off the wall.
The cut list
A cut list records the material, length and quantity of each piece. Cuts are made with a miter saw and a jigsaw, on 1×8 boards, 2x4s and plywood. The plywood forms the visible faces and arches, while everything hidden behind it is 1×8 and 2×4.
Tracing and cutting the arches
The arches are traced with a scrap piece of wood screwed in at one end, with a pencil hole at the other, working like a hinge. The bookshelves are 34 in. wide, so half of that, 17, sets the pencil position, giving a 34 total. The rule is to measure the bookshelf, divide by two, and that gives the arch. The curve is cut with a jigsaw, and a circular saw cuts the straight line across the top where the piece meets the ceiling. The jagged edges are smoothed with a sander.
Building the skeleton
Pieces between the bookshelves are cut snug to the ceiling and clamped. To avoid cracking the existing shelf wood, pilot holes are pre-drilled. These pieces set the spacing, make the unit look chunkier and add stability. The 2x4s are attached into the soffit to create a hidden perimeter frame for the plywood facing, and fasteners should go into studs. The skeleton includes a ledger for support and vertical pieces.
Finishing
The plywood arches are attached directly to the ledger. Trim molding finishes the edges, seams are caulked, holes filled, and the whole unit gets a coat of deep green paint. The video says hiring a custom carpenter would take longer than a weekend and cost much more.
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