Need your own space? Try this fun treehouse first if you are a kid this is a dad project so go get your dad and start building!

Supplies

Hammer, level, screwdriver, hand saw, skill saw, tape measure, pencil, string line, carpenter square

2x6” wood (spf painted, treated, or cedar for joists)
2x4” wood (spf painted, treated, or cedar for floor if no roof, walls, braces, roof truss, rails, steps, etc.) Deck screws (i.e. #8 x 3”) Nails (galvanized, 4” spikes and 3”) Plywood (½”+ for floor if roof, ⅜”+ for sides and roof) 4”x4” treated (for support posts if not completely supported by trees) Slides Bricks or concrete (for posts if post supported)

Step 1: Siting

Find a suitable location for the tree fort. Ideally situated in one or more trees (>=12” dia. at breast height) or on vertical posts. Think about size, height, and style (i.e. decks, balconies, additional platforms, slides, rope bridges, etc). A good size for main fort is 8” x 8” square, as walls and floors can easily be done with 8’ plywood, and this is a good size for sleeping in for 2 kids and an adult or 4 kids.

Step 2: Foundation

lengths to ensure adjacent posts are square). Dig hole 12-36” below grade to reach consolidated soWhere posts are needed, layout position with string and tape (typically stake in 2 perpendicular locations with string lines and set stakes 3’ past post locations check diagonalils, compact sand/gravel or natural ground by pounding 2x4” vertically at bottom of hole. Place bricks or pour 2-3” of concrete to creating footing for post. Place post, level and connect with other posts prior to backfilling. Backfilling should be compacted by pounding vertical 2x4” post following each placement of 2-4” lifts of soil. This approach should be suitable for up to 12’ high fort, higher elevation more effort required for the foundation (deeper and potentially larger posts).

When using posts, you may want them to extend above the floor to provide support for railings, slides, or roofs.

Step 3: Floor

Floor can be constructed using 2x6” wood. They can connect to the posts (screws or nails, or placed on top of posts cut to right height) or fastened to tree using 4-6” galvanized spikes/nails (trees don\t like treated screws but often in need of zinc). The main joists should be supported roughly 3’ to 8’ apart (this can be expanded but posts may need to be increased in size and main joist supports may need increasing to 2x8 or 2x10”). Additional cross joists can then be hung (metal joist hangers) or placed on top of the main joists every 16-24” if using plywood floor with 2x6” joists, or you can use 2x4”s for floor (supported every 3-6’ .. 3’ has minimal displacement, 6’ has very noticeable bounciness).

Ideally brade between adjacent joists if long spans used, to prevent joists from twisting (i.e. can just cut a shorter piece of the joist wood (i.e. 12-24” long) and nail or screw between the joists.

Step 4: Slide [optional]

Floor can be constructed using 2x6” wood. They can connect to the posts (screws or nails, or placed on top of posts cut to right height) or fastened to tree using 4-6” galvanized spikes/nails (trees don\t like treated screws but often in need of zinc). The main joists should be supported roughly 3’ to 8’ apart (this can be expanded but posts may need to be increased in size and main joist supports may need increasing to 2x8 or 2x10”). Additional cross joists can then be hung (metal joist hangers) or placed on top of the main joists every 16-24” if using plywood floor with 2x6” joists, or you can use 2x4”s for floor (supported every 3-6’ .. 3’ has minimal displacement, 6’ has very noticeable bounciness).

Ideally brade between adjacent joists if long spans used, to prevent joists from twisting (i.e. can just cut a shorter piece of the joist wood (i.e. 12-24” long) and nail or screw between the joists.

Step 5: Steps

Steps to the fort can be constructed by nailing 2x4”s to the tree or by nailing 2x4”s as rails and cross pieces and then attached to floor and lower cross members. Steps should be roughly 6-8” apart.

Step 6: Walls

Once the floor is complete the walls can be constructed with 2x4’s. A sill board should be laid out on the floor on its side, then place the wall studs butted against the sill board 8-24” apart (ideally with the first study spaced .75” closer so that centre of studs aligned with any seams in plywood walls. The wall studs should be cut all the same length and fastened to the sill stud with nails or screws. Add a single top plate to the studs. Frame in windows and doors, these can just be done with the 2x4s. Once 2 walls are constructed, they can be angled up and the sill plates screwed to floor. Once all 4 walls are placed up, and checked for square, then add the second top plate 2x4. The second sill should overhang the adjacent wall (for two of the walls). Once the walls are up, you can side with plywood or other siding. However, typical plank siding provides no torsional support, therefore you should still have plywood or cross members to provide torsional support.

Height of wall likely to be 4 to 7' (6' is good). The wall studs should be the finished height minus 4.5” to account for sill plate and double top plate. Finished height should work well for use of your plywood to minimise cuts. Roof may want to be done with a centre peak or single slope. If single slope one wall will need to be higher than the other.

Step 7: Rails

This is a good time to install the rails (if there is balconie, or there are no walls). The rails can be constructed of vertical 2x4” (ideally < 4” apart and 32-42” above floor). YOu may need some cross bracing to provide support for the rails at the ends.

Step 8: Roof

Roof can be constructed similar to floor or walls if single slope, and then placed on top of walls, sheathed with plywood, and then surfaced with tar paper and shingles.

If pitched roof, then the load is down as well as out. Typically the outward force is resisted by a cross member (horizontal) along the top of the sill plates. This may not be desirable if height is less than 6”. If span is small < 8-10’, then the horizontal cross brace can set higher up the roof profile. One approach construct a number of trusses such as the two opposing roof joists and a single cross member near the location of the ridge beam and a second temporary horizontal support between the joists at the wall level. Tack 2 or 3 of these trusses in place (each end and centre of walls), then add the ridge beam, then frame in the rest of the roof joists. Roof joists should be spaced same as the wall studs. Place plywood, over joists, then tar paper, then shingle starting at bottom and work way to ridge line. Alternatively, use painted plywood, corrugated plastic, or corrugated metal, or other materials for the roof.

Roof slope should be low enough so you are comfortable on top (likely 2.5H:1V at the steepest to 6H:1V), or you may need to set up anchors for safety lines (depends how high and what is below your treefort).