This is a variation of the one-board birdhouse available at Lowes.com. Their plan did not allow for an easy clean-out so I modified the floor and a couple of the joints.
Step 1: Materials and Tools
You will need:
1 ea. 1"x6" untreated cedar dog-eared fence board.
#6 x 1-1/4" screws
Drill with hole saw and 3/32" & 5/32" bits
Screwdriver to fit your #6 screws
Brad nailer and 1-1/4" brad nails (optional)
Tape measure & pencil
Step 2: Cut Some Wood
Cur the following lengths from your fence board:
2 ea. 9" pieces for the roof
2 ea. 8" pieces for the ends
2 ea. 5-1/4" pieces for the sides. You can cut these a bit shorter, 5-1/8", to allow some ventilation under the eaves.
1 ea. 3-7/8" piece for the floor
Lowe's cutting diagram for reference. I changed a couple of things.
Step 3: Drill, Baby, Drill
For the entrance hole, use an appropriate size for the bird species you want to attract. Center this on one of your 8" pieces, 3" from the bottom. If you are using a screw to hold the floor in place, center a 5/32" hole 3/8" from the bottom edge. Optionally, you can use a cabinet latch instead of the screw to hold the floor to give the house a no-tools clean out. If you plan on mounting this on top of a fence post as I did, you'll want to use a screw in the front. A cabinet latch would be unusable with this type of mounting. Think ahead, in other words.
Also, drill the 5/32" holes for the floor hinge screws now in the 5-1/4" side pieces. These would be drilled 1" from the back edge and 3/8" from the bottom edge.
If you use hummingbird feeders, you can use the scrap entrance hole plug for part of a cheap ant moat, I have another instructable that covers that.
Step 4: Mitre the Front and Back, Cut Bevel
Cut 45° angles on the front and back pieces. I use a radial arm saw so I set the beginning of the cut at 5-1/4" from the bottom edge, cut one side then flip it over and cut the other side.
I bevel the roof pieces and the floor piece with another 45° cut. I like the way they fit together this way. Lowe's plan call for a lap joint on the roof. You can do it this way also. Trim 3/4" from one roof piece in lieu of the 45° angle.
The bevel in the floor piece simply eliminates any interference in the floor pivot, but you can simply whittle off some of the back edge of the floor if you find it's binding when opening the floor.
Step 5: Glue and Fasten
Now you can glue and clamp the front and back to the sides. After the glue has cured, I put a couple of brad nails on each joint. Alternatively, you can drill and screw these joints.
At this point you'll want to attach the floor. It's harder to do after the roof panels are on. I know.
Move the side of the house to the edge of your workbench and place the floor in position, bevel side down. Through the pre-drilled hole in the bottom corner, drill a 3/32" pilot hole in the floor piece. Install this screw loosely. Repeat for the other side. Once you're happy with the way the floor is centered, drill the same hole in the front of the floor piece for the latch screw.
A note on painting. If your house and roof are to be different colors. Now is the time to paint them separately.
Step 6: Roof and Paint
After you have installed the floor, glue on the roof panels and secure them with nails/screws once the glue has cured. Depending on your glue, you may need to use a couple of pieces of masking tape across the ridge to hold them in place. I used Loctite PL375 adhesive in a caulking gun and didn't have this problem.
Paint it as you wish! My barn ad stencil was made by Etsy.com seller Glassy Witch, if you would like this stencil or something custom, look her up on Etsy. (Check out the Wikipedia page on Harley Warrick as he painted most of the "Mail Pouch" barns across the United States.)
Step 7: Optional Roof Reinforcement
If you cut the 45° bevels, you'll have some triangular pieces of scrap on the bench. You can glue this into the underside of the roof ridge. If you are drilling into the roof ridge to add eye screws, this just adds a bit more strength.
Step 8: Tin Signs
Another barn art idea I had was to use pop cans as tin signs. I used carpet tacks to attach them.