How to Build a Simple Birdhouse (Free Plans)

Here is how to build a birdhouse, in short: start with the bird you hope to host, get a plan made for that species, and cut it from untreated wood about 3/4 inch thick. Assemble the box with galvanized screws, drill drainage holes in the floor and ventilation holes near the top, add a sloped roof that overhangs the entrance, make one side open for cleaning, and leave off the perch. Those are the features NestWatch lists for a good nest box.

This guide walks through a simple box from plan to final screw, with a chickadee box as the worked example. Every measurement comes from a published plan or guideline that we link, because the right numbers change with the species. Where two sources disagree, we say so and explain how to choose.

Pick the Bird Before You Pick Up a Saw

A birdhouse stands in for a tree cavity, and cavity-nesting birds differ in the floor space, depth, and entrance they will accept. NestWatch’s Right Bird, Right House tool lets you choose your US region and main habitat and then shows which species you can build a box for. Run it before you buy lumber.

The entrance hole does most of the sorting. NestWatch notes that 1 1/4 inches is the smallest hole house sparrows can fit through and 1 9/16 inches the smallest for European starlings, so an entrance smaller than 1 1/4 inches keeps out both of those non-native species. Entrance size depends on the species, so look up the hole diameter your target bird needs before you drill; the chickadee example below uses one size. If you are building for bluebirds, bluebird houses and their placement follow conventions of their own.

Where to Get Free Birdhouse Plans

Three free sources are worth starting with:

• NestWatch species pages. The All About Birdhouses section links to plan pages for more than 60 species. Each page lists the entrance hole size, inside depth, floor dimensions, and mounting height, and offers a downloadable construction plan. The download form asks for an email address, and the page states that downloading subscribes you to NestWatch and Cornell email newsletters.
• NC State Extension, “Building Songbird Boxes.” This publication has a dimension table for small and medium songbirds, a cutout diagram of a basic box, a materials list, and a short list of construction hints. No sign-up is required.
• Nebraska Extension, “Birdhouses and Shelves” (G2002). This guide covers a wider range of birds, from house wrens to wood ducks and barn owls, and includes drawings of several ways to build an access door. Its height and timing notes are written for Nebraska.

Why plans for the same bird disagree

Compare the house wren in all three. NestWatch lists a floor of 5 1/2 by 5 1/2 inches, an inside depth of 8 inches, and a 1-inch hole. Nebraska Extension lists a 4 by 4 inch floor, a depth of 6 to 8 inches, and a hole of 1 to 1 1/4 inches. NC State groups house wrens with Carolina wrens on a 4 1/2 by 5 inch floor that is 6 to 8 inches deep. The tables overlap without matching, and Nebraska’s own table gives ranges rather than single values for several measurements. The practical rule is to choose one plan and use all of its numbers together, so the floor, depth, and hole height stay consistent with each other.

Materials and Tools

Wood

NestWatch recommends untreated, unpainted wood, preferably cedar, pine, or cypress, with walls at least 3/4 inch thick to insulate the nest. Nebraska Extension adds poplar to the woods that are easy to work and weather well, and notes that cedar is durable. Skip pressure-treated lumber: NestWatch specifies non-pressure-treated exterior plywood even for its large owl boxes, and NC State advises against treating the wood with a preservative.

Board sizes at the lumberyard are nominal. Both NestWatch and Nebraska Extension point out that boards sold as 1 inch thick actually measure about 3/4 inch, so an ordinary “1-by” board meets the thickness guideline. Measure the width with a tape as well before you lay out any cuts, rather than relying on the label.

Fasteners

NestWatch recommends galvanized screws because nails can loosen over time and let rain in, and screws are easier to remove for repairs. It says not to use staples. NC State’s materials list uses galvanized nails 1 1/2 to 1 3/4 inches long, and Nebraska Extension calls screws “probably best of all.” Whichever you choose, make sure no point pokes through into the inside of the box; Nebraska Extension notes that protruding points can injure the birds.

Tools

NC State’s list for building is short: a tape measure, a pencil or chalk, a saw, and a hammer. If you use screws, add a drill or driver. You will also need drill bits that match the entrance, drainage, and ventilation hole sizes in your plan, plus coarse sandpaper for the inside of the front panel. For installing the box, NC State lists a ladder, fasteners (3-inch galvanized nails, lag bolts, or crimped wire), and sheet metal for a predator guard.

Before you start, read the manual for each power tool you plan to use, wear eye protection, and clamp small pieces to the bench instead of holding them near a blade or bit. If a tool is new to you, have someone who has used it show you first.

Example Plan: A Simple Chickadee Box

A chickadee box makes a good first project: it is small, and NestWatch’s black-capped chickadee page and NC State’s table agree on its main measurements. The table shows the key numbers and where each one comes from.

That 1 1/8 inch hole is smaller than the 1 1/4 inches NestWatch gives as the minimum for house sparrows, so house sparrows cannot use this box. The NestWatch page also suggests placing 1 inch of wood shavings on the box floor. Use a wood other than cedar for the shavings, since Nebraska Extension does not recommend cedar shavings for lining boxes.

How to Build a Birdhouse, Step by Step

1. Mark and cut the panels

A basic box has six parts: front, back, two sides, floor, and roof. Lay them out on the board following your plan. NC State reminds builders to allow for the width of the saw blade when marking, so cut on the waste side of each line rather than down the middle of it.

Inside dimensions are what the bird cares about, so add wall thickness when you work out panel widths. For the chickadee box, if the floor fits between the four walls and the front and back cover the edges of the sides, the sides are 5 1/2 inches wide and the front and back are 7 inches wide (5 1/2 plus 3/4 for each side wall). Panel heights depend on the roof slope your plan uses, so take those from the plan itself.

2. Drill the entrance and ventilation holes

Drilling is easier while the panels are still flat on the bench. Mark the entrance on the front panel at the height your plan gives, and use a bit or hole saw of exactly the listed diameter; Nebraska Extension notes that birds can be particular about hole size, so the measurement should be fairly exact.

For airflow, NestWatch calls for two 5/8 inch holes near the top of each side wall, four in total. NC State suggests several 1/4 inch holes in the sides, and Nebraska Extension offers either a 1/2 inch gap under the eaves or several holes of 1/4 to 5/16 inch along the top of the sides. The three sources size vents differently, so use whatever your chosen plan specifies.

3. Roughen the inside below the entrance

Young birds have to climb up the inside of the front panel to leave the box. NestWatch suggests roughening smooth boards with coarse sandpaper. Nebraska Extension describes sawing grooves 1/8 inch deep or punching dents with a screwdriver below the hole. NestWatch adds that a series of shallow horizontal cuts, like a small ladder, works well in medium-sized boxes for swallows and bluebirds.

4. Prepare the floor for drainage

Some rain will get in, so the floor has to let it out. NestWatch recommends at least four drainage holes of 3/8 to 1/2 inch in the floor, or cutting off the corners of the floorboard instead. NC State calls for at least four 1/4 inch holes and also mentions the cut-corner option. NestWatch also advises recessing the floor at least 1/4 inch up from the bottom edge of the walls, which keeps the nest drier and helps the box last longer.

5. Assemble the back, sides, floor, and front

Fasten the fixed side to the back, set the floor in place with its recess, then attach the front. Leave the second side unfastened for now, because it becomes the door. Drill pilot holes before driving screws near the ends of a board; NC State recommends starter holes for nails in hardwood to keep boards from splitting. Run a hand along the inside before moving on and back out any fastener that comes through.

6. Make one side open for cleaning

NestWatch recommends a hinged side for cleaning and monitoring, with a latch or nail that keeps the box closed until you open it. NC State suggests either hinging the roof or using a pivot nail on one side, and Nebraska Extension shows side doors that swivel out as well as hinged tops. A pivoting side is the simplest for a first build: hang the loose side on two nails or screws driven through the front and back near its top edge so it swings outward from the bottom, then hold the bottom closed with a nail or latch.

7. Add a sloped roof with an overhang

NestWatch recommends a sloped roof that overhangs the front by 2 to 4 inches and the sides by 2 inches, which keeps out driving rain and makes it harder for predators to reach in. It also suggests 1/4 inch deep cuts under the roof on all three edges to act as gutters that channel rain away from the box. If you plan to mount on a pole, NestWatch notes that leaving a few extra inches of back panel above and below the box, or pre-drilling mounting holes in the back before assembly, makes installation easier.

8. Leave off the perch

If your plan or a store-bought design shows a peg under the hole, leave it off. NestWatch says a perch is unnecessary for the birds and can help predators get into the box, and NC State adds that it gives competitors such as house sparrows easier access.

Mounting and Predator Guards

Raccoons and climbing snakes are the reason NestWatch recommends mounting on a metal pole with a baffle. It describes three options: a cone baffle (a metal collar about 3 feet across around the pole under the box), a stovepipe baffle (generally 8 inches in diameter and 24 to 36 inches long), and a Noel guard (a wire mesh tube on the front of the box, used with another guard or on boxes mounted to trees). Nebraska Extension also notes that houses on metal poles are less exposed to predators than those on a wooden post or tree.

If you need a ladder to mount the box, NC State advises working in teams with folding or extension ladders. Set the box at the mounting height your plan lists; for the chickadee box above, NestWatch gives 5 to 15 feet.

After the Build

The door you built is there to be used. Nebraska Extension recommends cleaning boxes before each nesting season and right after a brood leaves, and checking them about once a week to keep house sparrows or starlings from taking over.

If you would rather buy than build, look for the same features in a ready-made birdhouse: untreated wood at least 3/4 inch thick, drainage and ventilation holes, a roof that overhangs the entrance, a side or top that opens, and no perch. More nest box guides are collected in our Birdhouses section.

Birdhouse Building FAQ

Where can I find free birdhouse plans?

NestWatch offers free construction plans for more than 60 species, though the download asks for an email address. The NC State and Nebraska Extension publications linked above give simple birdhouse plans, as dimension tables and diagrams, with no sign-up. Pick one plan and follow all of its measurements.

Should I paint or stain a birdhouse?

The sources differ. NestWatch recommends unpainted wood, and NC State advises against painting or using a preservative because the box may absorb too much heat or give off toxic vapors. Nebraska Extension says cedar does not need paint, but that exterior latex on the outside can extend the life of a pine or poplar box; it recommends natural tones and says never to paint the interior or the entrance hole. None of the three addresses stain. Building with unpainted cedar avoids the question.

Can I use plywood, pressure-treated wood, or scrap lumber?

Avoid pressure-treated wood. NestWatch mentions plywood only for larger owl boxes, and then specifies non-pressure-treated exterior grade. Scrap lumber is fine if it is solid and untreated; Nebraska Extension suggests reusing scrap wood from other projects to save money and cut waste. Check the thickness, since the 3/4 inch guideline still applies.

Can a birdhouse be made of metal or plastic?

Nebraska Extension advises against metal because it tends to get too hot, with one exception: purple martin houses, which are usually lightweight aluminum so they are easier to raise and lower. The same guide lists PVC pipe and gourds as workable materials alongside wood. Nebraska Extension calls any good, solid, untreated wood generally the best construction material.

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