How to Build a Unique Three-Unit Condo Birdhouse (Multi-Family Birdhouse Plans)
Out With the Old. In With the New.
After many years, our old birdhouse had seen better days. It was perched in a prominent location in our garden where year after year, we enjoyed watching families of bluebirds and wrens raise their young. The worn and weathered wood has stoically withstood the harsh New England climate and even endured some chewing from a family of flying squirrels. Though the birdhouse is still solid and offers a safe haven for the birds, it looks a little shabby. So I decided it was time to make a replacement.
Three Basic Boxes
The three-unit condo birdhouse may look complicated but it's really a simple project. Two of the birdhouses are just basic boxes with a peaked roof. All of the angles are cut at 45-degrees and the joinery is simple. The only tricky bit is fitting the little shed against the two larger birdhouses. We'll get to that later.
The Cutting List
I made the condo birdhouse units from various pieces of new and used wood along with some salvaged materials and a few pieces from my scrap bin. Birdhouses are great projects for reusing pieces of old wood that aren't suitable for fine furniture and similar projects. I like to scrounge and salvage different types of abandoned wood ranging from discarded pallets to renovation debris. For this project, I used a few scraps of mahogany decking for the base, a short piece of salvaged pine shiplap for some of the roof sections, some pine shelving and remnants from a painted window box along with some new wood purchased at the local home center.
Cut pieces of lumber into the following dimensions. The roof peaks on the front and back sections of the two larger units are cut at a 45-degree angle (I used a power miter saw). The sloped shed ends are also cut at a 45-degree angle.
Base: 14" x 14"
- Front = 15" H x 6-1/2" W
- Back = 15" H x 6-1/2" W
- Sides (2) = 11-1/4" H x 4-1/2" W
- Roof A = 7-1/2" L x 6-3/4" W
- Roof B = 7-1/2" L x 6" W
- Floor = 5" L x 4-1/2" W
- Front = 12" H x 5-1/2" W
- Back = 12" H x 5-1/2" W
- Sides (qty =2) 9" H x 3-1/4" W
- Roof A = 5-1/2" L x 5-1/2" W
- Roof B = 5-1/2" L x 4-3/4" W
- Floor = 4" L x 3-1/4" W
Small shed birdhouse:
- Front = 7-1/4" H x 5" W
- Back = 6-1/2" H x 4-1/4" W
- Ends (qty = 2) 7-1/4" L x 5-1/2" W
- Roof = 9" L x 9" H
- Chimney = 3/4" square x 4-1/4" L
Step 1: Making an Entrance
The size of the entrance hole is important for attracting bluebirds and wrens. Too small and birds can't enter the birdhouse. Too big and the larger (and more aggressive) starlings and sparrows will move in.
Eastern bluebirds fit comfortably through a 1-1/2" diameter entrance hole. In areas with Western or Mountain bluebirds, increase the entrance to 1-9/16" diameter. Wrens prefer a smaller 1-1/4" entrance hole.
I used a a 1-1/2" Forstner bit to drill the entrance holes in the front section of each birdhouse. I considered drilling a 1-1/4" entrance for the small shed section but since the old shed nest box was often occupied (and chewed) by flying squirrels, I drilled a 1-1/2" hole in the right side section. I'm hoping that the squirrels will like the new digs.
Step 2: Assembling the Nest Boxes
The birdhouses are simple boxes: the front and back pieces are attached to one side with glue and nails. The opposite side pivots on two screws, creating a hinged door that opens for access to the inside. Since the boxes fit together on the base, it's important to position the hinged door on the opposite side from the little shed unit. Looking at the front of the largest birdhouse, the hinged door is on its left side. Looking at the front of the mid-sized birdhouse, the hinged door is on its right side.
Start by building the largest birdhouse. Position the front piece against the right side section, aligning the bottom edges together. Attach the pieces with glue and weather-resistant nails or screws (I use a pneumatic nailer). Then, position and attach the back section to the subassembly.
Please note: the top edge of the side piece will not meet up flush with the angled roofline of the front section. This is intentional and in the fully assembled birdhouse, this creates a small gap under the roofline for air circulation.
Attach the two roof sections together at a 90-degree angle, positioning the 6-3/4" wide piece so that it overlaps the 6" wide piece. This forms a peaked roof but do not attach the roof to the birdhouse yet. Put the roof assembly aside until later.
Step 3: Make a Simple Hinge
The left side is attached to the subassembly with just two screws that are positioned carefully to form a pivot point: one screw through the front piece and into the edge of the side, the second screw directly opposite through the back piece and into the other edge of the side. This creates a hinged side door that opens easily for cleaning out the interior.
Line up the bottom edge of the left side piece with the bottom edges of the subassembly. Then on the front section, measure down 2" from the point where the angle of the peak nearly meets the top edge of the side. Drill and countersink a hole through the front section, and then attach the pieces together with a weather-resistant screw. Using a square or straight edge, transfer the location of the screw across the side piece to the back section. Finish attaching the door by driving another screw through the back and into the edge of the door, forming a pivot point. The door should swing open easily.
Repeat the assembly process for the mid-size birdhouse EXCEPT position the hinged door to right side of the birdhouse. The doors of each birdhouse will be on the opposite side of the small shed nest box and will open for easy access.
Step 4: Fitting the Floor
The floor sections are cut to fit snuggly into the base of the birdhouses. The floor of the large birdhouse is approximately 5" long by 4-1/2" wide. The floor of the mid-size birdhouse is approximately 4" long by 3-1/4" wide.
Test the fit and trim the floor pieces (if needed), but do not attach the floors to the nest boxes. Instead, the floors will be positioned and attached directly to the base. Speaking of the base....
Step 5: Building the Base
The 14" by 14" square base is the foundation for the condo units. The original base was made from two pieces of 1/2" exterior plywood and while this worked well, I decided to make the new base from scraps of mahogany decking that were salvaged from a neighbor's renovation project.
The mahogany planks are 5-1/2" wide and the side edges are milled with a slight round over. Before edge gluing the planks together, I ran each piece through the table saw to trim about 1/8" of material from each edge. This squares up the boards for gluing.
After spreading an even coating of exterior glue along all of the edges, I clamped the boards together and set the assembly aside to cure.
When the glue dried and with the clamps removed, I used my table saw to rip the base to 14" wide. Then, I used my homemade panel cutting jig to trim the ends to a finished length of 14" long.
Step 6: Positioning the Condos on the Base
Now it's time to determine where to position the individual units on the base. I started by placing the two larger birdhouses back-to-back on the base, with the doors opening away from the shed unit. I slid the shed unit into place, aligning the units together and (more or less) centering the three units on the base. When I was satisfied with the positioning and arrangement, I traced around the base of each unit to mark its location.
Starting with the largest birdhouse, I inserted the floor through the open door. Holding the floor in place, I carefully removed the birdhouse and then attached the floor to the base with screws. With the floor secured to the base, re-check the positioning of the birdhouse.
To attach the birdhouse to the base and to keep the door closed, drill and countersink a screw hole along the center of the bottom edge of the pivoting side. Use another screw to secure the door to the floor. This will hold the unit securely in place, yet removing the screw allows easy access or to remove the unit from the base.
Repeat the process with the mid-size unit. Place the birdhouse back-to-back against the larger unit. The mid-size unit is inset by 3/4" on the left side and 1/4" on the right side. The inset is visible in the photo (above).
Step 7: Add the Shed Unit
With the two larger birdhouses positioned and secured to the base, it's time to fit the shed unit into the condo complex. This is a bit fiddly and takes some trial and error to get a nice fit. The basic dimensions in the Cutting List are a good starting point and should be close.
I temporarily clamped the small shed unit is together without any glue. The side section fits between the angled end pieces.
The shed is positioned between the other two units. The exact location is not critical; place the shed where it looks good to you. The edge of the right end fits up against the side of the smaller birdhouse. The left end fits up against the larger unit.
Since the positions of the two larger birdhouses are staggered, it will be necessary to reduce the width of the left end piece of the shed. Trim the long edge of the piece to reduce the width as needed until the shed unit fits up against the staggered inserts of the birdhouses and is square to the edges of the base. Getting a good fit is easier than it sounds but may take a couple of attempts. Trim a little at a time from the long edge, then test the fit.
When you are satisfied with the fit and alignment of the shed, attached the ends to the side piece with glue and nails. Place the shed on the base and then position two small triangular pieces inside the base area of the shed. These will be the anchor points to secure the shed to the base. Pre-drill the small pieces before attaching the anchor points to the base to reduce the chance of splitting the wood. To attach the shed to the base, drill and countersink a hole through the side and into one of the anchor points. Secure the shed to the base with another screw. We're almost there!
Step 8: Drill the Drainage Holes
The photo (above) shows the layout of the floors and anchor points for the three units. I drilled 3/8" diameter holes through the base in the clipped corners of the larger units, plus two more in the two open corners of the shed. Instead of drilling through the anchor points, the last drainage hole is centered between the corners.
Step 9: Raising the Roof
The top edge of the shed roof is cut at the same 45-degree angle as its sloped end pieces. I made the first cut by tilting the table saw blade to 45-degrees.
The second 45-degree cut is bit tricky: we need to cut a notch in the roof so that it fits tightly up against both of the larger units. This creates the stepped roofline.
Step 9: (Shed Roof Continued)
Start by centering the roof on top of the shed and up against the larger birdhouse. Mark the point where the right corner of birdhouse meets the roof. This represents the length of the cut needed to create the notch.
The width of the notch is determined by the depth of the inset between the two larger units. Determining the exact width needed for the notch is challenging so to reduce the risk of cutting the notch too wide, I outlined an area that was narrower than needed. The initial outline for the notch is shown in the photo (above).
Step 9: (Shed Roof Continued)
To make the cut, I positioned the fence so that the 45-degree tilted blade was just inside the outline of the notch. Run the roof through the saw, stopping just before the end of the outlined notch as shown in the photo (above).
If the notch is not wide enough, move the fence slightly and try again. It took me two attempts to get the right width for a good fit.
Step 9: (Shed Roof Continued)
To cut the length of the notch, I flipped the roof section over. Using a small handsaw, I made the cut to reveal the notch.
Test fit the shed roof against the two other birdhouses, and make any adjustments as needed. The fit should look good but it doesn't have to be perfect; the birds won't mind.
The Finishing Touches: A Little Touch Up and a Little Paint
The condo units are almost done but still look a little rough—especially since I used a mixture of new and old wood. To get the units ready for paint, I filled the nail holes with putty, sanded all of the edges and rounded over the corners. Breaking the sharp edges gives the birdhouses a finished look and allows the paint and stain to adhere better.
I painted the large unit blue and painted the other units red. All of the roofs are stained with the same shade of brown. Only the outside is painted or stained, leaving the interior surfaces natural for the safety of the baby birds.
After the stain dried, I attached the roofs to the units, filled the nail holes and touched up the putty with a little more stain.
To add a little variety and a bit of whimsy, I like to add small details that transforms each birdhouse into a unique piece of folk art. I especially like the rustic country look, and it's fun to attach found objects and other interesting items that I find at flea markets and yard sales.
The picket fence on the blue unit were cut from the slats of an old pallet. I ripped the slats into pieces that are approximately 3/8" x 3/8" square. The lengths are staggered at random lengths, with the top ends cut at 45-degree angles and then attached with glue and short brads. The awning over the entrance is a repurposed drawer pull. The decorative ceramic perch is another repurposed drawer pull.
The awning over the entrance hole of the red unit is a vintage brass drawer pull. The front also features a decorative metal eagle medallion.
The chimney on the shed is 3/4" by 3/4" by 4-1/4" long piece of pine. The end is cut at a 45-degree angle to match the slope of the roof and painted black.
The new three unit condo is ready to take its place in the garden. The old birdhouse is still solid and ready for new occupants, and I will relocate it another spot in the yard. Nothing goes to waste.
Do You Have Birdhouses in Your Yard?
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
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© 2019 Anthony Altorenna