Shop Notes · Build Guide
Resaw a single cedar 1×6 into two thin boards and you have nearly every part a nesting pair needs. Add a few dollars of hardware-store flashing for the roof and a side that swings open to clean, and the result is light, weatherproof, and built to the right dimensions.
Cedar is the natural choice for anything left outside: it resists rot and insects on its own, stays light, and needs no finish inside — which matters with birds living in it. A nominal 1×6 is a hair under ¾″ thick and 5½″ wide — just enough width for a bluebird’s floor.
The move that makes one board go so far is to resaw it: stand it on edge, run it through the bandsaw, and one ¾″ board becomes two thin ones — double the area for the price of one board. A 3-foot 1×6 holds every cedar part with room to spare; four feet leaves margin for a first attempt, six feet makes two boxes.
A real ¾″ board resawn down the middle yields two halves around 5⁄16″–⅜″ after the blade’s kerf and a cleanup pass. Nothing here is fussy about a sixteenth — the cut list calls ⅜″, but anywhere in that range works. Use a bandsaw with a sharp resaw blade.
A birdhouse can look like anything, but a bluebird house has to hit a few specific numbers — the same opening that admits a bluebird either keeps a starling out or lets it in. Kansas City is Eastern bluebird country, so these are the ones to hold to. Get the hole and the no-perch rule right; the rest has comfortable tolerance.
Front elevation. Hold the hole size and its height exactly; the floor can vary half an inch either way.
Start with the entrance. A 1½″ round hole passes an Eastern bluebird and keeps out a European starling, which can’t fit through anything smaller. Drill it clean with a spade or Forstner bit, and don’t enlarge it.
Set the hole about 6–7″ above the floor — high enough to keep nestlings below a reaching paw, and high enough that fledglings must climb to leave. Give them a grip: roughen the inside of the front below the hole, or saw a few shallow kerfs across it.
Leave the perch off. Bluebirds don’t need one, and it only gives house sparrows and predators a foothold.
Round, for an Eastern bluebird. (Out west, Mountain bluebirds want 1 9⁄16″.) Never larger — that’s what keeps starlings out.
Measured to the center. Anywhere from 6 to 7 inches works; this is what one 1×6 gives you.
Interior. A bluebird is happy anywhere from 4″ to 5½″ square — right where the board’s width lands.
None, on purpose. A peg below the hole only helps competitors and predators get a grip.
The resawn stock. Thin and light, and cedar doesn’t need bulk to last outdoors.
Two ¼″ vent holes high in each side; the four floor corners clipped off so rain drains away.
Six cedar parts, all ⅜″ thick once resawn, plus one piece of metal that isn’t from the board. Laid out, the box uses about 29 inches of a 36-inch board — so a 3-footer does it, with a few inches left over for a mistake.
| Part | Qty & size | Notes |
|---|---|---|
| Back | 1 — 5½″ × 14″ | Full board width. Runs long top and bottom to give two mounting points on the post. |
| Front | 1 — 5½″ × 9″ | Carries the 1½″ hole, center 6¾″ up. Kerf the inside below the hole. |
| Sides | 2 — 4¾″ × 10½″ | Top edge cut on a slope, 10½″ at the back down to 9″ at the front. One side becomes the door. |
| Floor | 1 — 4¾″ × 4¾″ | Four corners clipped ½″ for drainage. Set up ¼″ from the bottom edges. |
| Roof deck | 1 — 5½″ × 6″ | Screws down to the sloped wall tops; the metal cap fastens to it. |
| Metal cap | 1 — ≈ 8″ × 10″ | Not cedar — a piece of hardware-store flashing. See the next section. |
Nesting plan. The full-width parts (back, front, roof deck) come off one resawn board; the narrower sides and floor off the other, with the offcut strip good for cleats.
Cedar at ⅜″ splits if you crowd an edge, so pre-drill every screw and keep fasteners back from the ends. Use coated or stainless exterior screws — bare steel bleeds rust into the wood. A little exterior glue at the fixed joints is fine; leave the door and roof screwed only, so a cracked part can be swapped.
A good roof has to overhang, carrying the drip line out past the entrance so rain never runs into the hole. But the board is only 5½″ wide — the exact width of the box, with nothing to spare for an overhang. A few dollars of metal solves that.
Cut a cedar roof deck (5½″ × 6″) and screw it down onto the sloped wall tops — high at the back, low at the front, so water runs off the front. Then cap it with a piece of aluminum or galvanized valley flashing from the roofing aisle, cut a few inches bigger all around so it projects ~3″ over the hole and about ¾″ past each side.
Snip it with tin snips, bend a ¾″ hem down on the front and side edges over a clamped board — that stiffens it, hides the raw edge, and makes a clean drip line. Fasten it to the deck with four short screws and rubber washers, and run a bead of sealant where the back edge meets the mounting board.
Side section. High at the back, low at the front; the metal projects past the entrance so the drip line falls clear of the hole.
One side hangs between the front and back on two screws and drops open from the bottom. Back out the single lock screw and it swings; drive it home and it’s shut.
Bluebirds raise two or three broods a season, and each leaves a packed nest behind. The box has to be cleared out between them, so one side is built to open.
The simplest durable mechanism: make one side the door, sized to drop between the front and back. Run two screws — one through the front, one through the back — into its top edge on a common line, and they act as the hinge. The door swings out from the bottom; a single screw at the lower front holds it closed.
To clean it, back out that one screw, tip the side open, and clear out the old nest.
Mill the stock. Resaw the 1×6 into two ≈⅜″ boards and clean up the faces. Cut all six parts to size; slope the side tops 9″ (front) to 10½″ (back); clip the floor corners.
Open the front. Bore the 1½″ hole, center 6¾″ above the floor line. Saw three or four shallow kerfs across the inside below it. Drill two ¼″ vent holes high in each side.
Make the U. Join the front, the fixed side, and the back around the floor — floor set up ¼″ from the bottom edges so end grain isn’t sitting in water. Leave the fourth side off.
Hang the door. Drop the last side into place and run the two pivot screws through the front and back into its top edge; add the lock screw at the bottom.
Cap it. Screw the roof deck to the wall tops, bend and fasten the metal cap with washered screws, and seal the back seam.
Finish — outside only. Leave the interior bare wood. Outside, let it silver naturally or wipe on raw linseed oil or a light exterior stain. Keep it light-colored so the box stays cool.
Mount the box 5–6 ft up on a smooth metal pole (far better than a tree or fence — raccoons and cats can’t climb it; add a baffle below for certainty). Face the hole toward open ground and away from prevailing storms — east or northeast is a good default here. Keep it out in the open, away from heavy brush and bird feeders, and clean it out after each brood.