Three Story Birdhouse / No Supports! Improved!

Update 6/16/25: New cosmetic improvements! Dormer now uses inserts so color can match house color. Dormer inserts slide straight up into the dormer roof and are held in place by the wall below (see photo). Made the mortise and tenons blind, so they are not visible on the outside for a cleaner look. I also slightly rounded over the corner of the entrance hole and added small chamfers to the support arms. Please let me know what you think!

I also simplified the filenames and removed the smooth roof options. There are still two options for the full roof sections, dormer or regular (flat).

For the mounting arm, I suggest using 3 or 4 perimeters and 25% cubic infill.

Thanks! Original description below.

A fun birdhouse design I came up with originally to make out of wood using my laser cutter. I converted my 2D drawings to 3D solids for 3D printing. Obviously an outdoor resilient material like PETG (what I used), ASA, etc. is recommended. I printed with 2 perimeters and 15% grid infill. I also used a brim for the sides and roof components to help with adhesion, even with the CoreOne. Some (on my MK4S) still had a bit of lifting. In the photos, the bottom house (pistachio green) is my first version, with smooth sides but I used a negative volume SVG wood grain. I decided to simply model the sides with slats instead. There are two options for the roof components. One is smooth, which you can leave smooth or add a shingle pattern as a negative volume as you can see I did for the bottom and top house. The other option is shingled in the model, so just print as is (as on the middle house). I also added a “Dormer” as an option for the roof of the top floor house. You can do just one side, or both sides. I suggest assembling without any adhesive to begin with. The fit is pretty snug so may not even need any, but still wait on the glue as you will likely want to take it apart as you figure out the assembly. Start with the bottom house, with the roof pieces. Assemble the middle house complete, then install the middle house to the lower house, straight down. For the support arms, there is one that is special and needs to attach to the middle house, closest to the roof of the bottom house (see photos!). The bottom house floor and mounting arm use #10 hardware (I used 10-24 stainless screws and nylock nuts). The clean-out doors on the back of each house is print-in-place. There are small ‘Door Locks’ that are installed with small screws to lock the door closed, and must be turned so the flat of the door lock is towards the door for it to open.

You can also print this as a single story birdhouse using just the Top story sides and roof, and the bottom story floor. 

Also, two story using only the bottom and top portions. You can also go four story or more using multiple middle floor pieces!

The mounting arm seems a little flimsy once I mounted it, so I will update that to make it more stable. It has clearance to mount on a wall, or post.

I actually didn't use any adhesive on my model. However, probably could use some in certain locations to help maintain integrity. Filing or trimming any ‘flash’ on the corners of the tenons (the male rectangular piece that plugs into the female rectangular openings) can help with the fit, if it is too tight.

If the filenames have a B, M or T in it, that indicates Bottom, Middle and/or Top birdhouse. Also, there may be a 2X or 3X to indicate how many of those parts are required. Keep in mind there are two roof style options, smooth or shingled.

Please post your makes, comments, questions or suggestions!

Update 5/20/25: Now with dormer option for the bottom and middle birdhouse! Also, what should be a stiffer mounting arm.

Added illustrations with some of the components to show assembly detail and part orientation. NOT ASSEMBLY SEQUENCE!

Update 5/22/25: updated mounting arm for strength.