What you’ll build
Two gable frames, each made from two posts and two rafters, stand at the front and back. Base rails and a center joist tie them together under an eleven-board deck, a ridge beam and four purlins form the roof frame, and rails along both side walls stiffen the frame and hold two 1x8 shelves. The posts and rafters need angled cuts: 22.5° at the eaves and 45° at the peak.
Shopping list
Buy these boards. The list fits every cut onto standard lengths and leaves ⅛″ for each saw cut and ¼″ for trimming board ends.
| Lumber | Length | Qty |
|---|---|---|
| 2x4 | 8 ft | 18 |
| 1x6 | 8 ft | 14 |
| 1x8 | 8 ft | 2 |
Cut list
Every part, grouped so you can cut matching pieces together. Sizes are actual dimensions (a 1x4 is ¾″ × 3½″). Check them against your own boards before cutting.
| Part | Lumber | Section | Length | Qty | End cut |
|---|---|---|---|---|---|
| Base rails, ridge beam, purlins, post rails | 2x4 | 1 ½″ × 3 ½″ | 77″ | 11 | Square |
| Deck Board | 1x6 | ¾″ × 5 ½″ | 80″ | 11 | Square |
| Slat | 1x6 | ¾″ × 5 ½″ | 72″ | 3 | Square |
| Apron | 2x4 | 1 ½″ × 3 ½″ | 65″ | 2 | Square |
| Left Leg | 2x4 | 1 ½″ × 3 ½″ | 36 ¾″ | 2 | 22.5° off square |
| Left Rafter | 2x4 | 1 ½″ × 3 ½″ | 50 ⅞″ | 2 | 45° off square |
| Right Rafter | 2x4 | 1 ½″ × 3 ½″ | 50 ⅞″ | 2 | 45° off square |
| Right Leg | 2x4 | 1 ½″ × 3 ½″ | 36 ¾″ | 2 | 22.5° off square |
| Shelf | 1x8 | ¾″ × 7 ¼″ | 77″ | 2 | Square |
| Support | 2x4 | 1 ½″ × 3 ½″ | 67″ | 1 | Square |
Tools
- Tape measure
- Pencil
- Speed square
- Drill
- Eye & ear protection
- Miter saw
- Clamps
Step-by-step instructions
Assemble Front Gable Frame
Lay the two 36 3/4-inch front posts flat on a level work surface. Position the two 51-inch front rafters together at the ridge peak miter, then align their lower ends flush with the mitered tops of the posts.
Assemble Rear Gable Frame
Lay the two 36 3/4-inch rear posts and two 51-inch rear rafters flat, matching the front gable layout. Align the 45-degree peak miters and the 22.5-degree eave joints flush on both sides.
Assemble Floor Base Frame
Stand the front and rear gable frames upright with helper support. Position the two 77-inch side base rails between the posts, align the 65-inch front and rear rails flush across the bottom, and set the 67-inch center joist squarely between the side rails.
Install Side Wall Rails
Position the two 77-inch lower post rails horizontally along the inside of each wall to establish shelf support height. Place the two 77-inch top post rails against the upper inside post edges beneath the eaves, locking both side walls rigid.
Install Ridge Beam and Purlins
Fit the 77-inch ridge beam directly under the gable peaks from front to back. Position the four 77-inch roof purlins across the rafters—two on each roof pitch—keeping their outer faces flush with the sloped rafter edges.
Lay Floor Deck Planks
Set the eleven 80-inch 1x6 deck planks flat across the base joists from left to right. Align the front and rear board ends flush with the outer perimeter rails, maintaining uniform spacing between planks.
Attach Rear Headboard Slats
Position the three 72-inch 1x6 headboard slats horizontally across the exterior face of the rear posts. Start with the lowest slat just above the base and space the remaining two slats upward, keeping the side ends flush with the posts.
Mount Interior Side Shelves
Rest the two 77-inch 1x8 shelf boards flat on top of the left and right lower rails. Slide each board snug between the front and rear posts until fully seated.
Build on level ground, sand every edge and corner a child can reach, and check the frame for wobble before anyone climbs on it. If you leave it outdoors, use lumber and fasteners rated for outdoor use and inspect it each season.
Change the size or design
This plan is one of the projects in the TimberLab app’s catalog. In the app you can turn the model in 3D, follow the assembly steps one part at a time, and ask for changes in plain words, such as “make it 6 inches shorter” or “add a shelf”. The cut list and shopping list update to match the new design.
Questions about this plan
How much lumber do I need to build this outdoor play cabin?
The shopping list calls for 18 × 2x4 at 8 ft; 14 × 1x6 at 8 ft; 2 × 1x8 at 8 ft. It groups every cut onto standard board lengths and leaves room for saw cuts and trimming the board ends.
How big is the finished outdoor play cabin?
It is 72″ wide, 72 ¾″ tall, and 80 ¾″ deep.
What tools do I need?
You need a tape measure, pencil, speed square, drill, eye & ear protection, miter saw, clamps.
Can I change the size of this outdoor play cabin?
Yes. Open the outdoor play cabin in the TimberLab app and describe the change in plain words, such as “make it 6 inches shorter”. The 3D model, cut list, and shopping list update together.
