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Big six-post tree fort plan

120 sq ft, deck 6 ft up, gable roof.

21 of 21 planner checks passed
The big six-post tree fort, drawn by the treehouse designerThe big six-post tree fort with its width, length and deck heightThe frame of the big six-post tree fort: footings, posts, beams, joists and braces, without the walls and roofThe big six-post tree fort seen from above, with the deck, the way up and the use zone
Drawn by the designer from this plan
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Preliminary checks for 20 psf ground snow and a 12 in frost line. Local approval not checked.

Footprint
10x12 ft
Deck height
6 ft
Posts
6 x 6x6
Way up
Stairs

About $6,104 in materials, before sales tax, delivery and tools.

Building it? The $29 builder's plan dimensions every piece. See sample sheets

Planner checks

Preliminary checks passed for the loads you entered. Local approval not checked.

Each bar is how much of its span table limit a joist, beam, post or rafter uses. A member over 100% fails: it goes up a size or gets another post.

  • Decking100% of the table limit2x6 PT, 1' 4" span
  • Edge beams92% of the table limit2-2x8, 6' span
  • Floor joists85% of the table limit2x8 at 16 in, 10' span
  • Roof beams82% of the table limit2-2x8, 6' span

what this design uses room to spare

Green passes the rule or the calculation we checked against, amber asks you to look at something before you build, red fails it. These are preliminary checks, not a structural approval; your local building authority reviews and approves.

Specification

The Big six-post tree fort, part by part.

The structure

Footprint
10x12 ft, 120 sq ft
Deck height
6 ft
Roof
Gable roof
Way up
Stairs

The frame

Posts
6 x 6x6
Joists
2x8 at 16 in
Beams
2-2x8
Bracing
Knee braces both ways

Cost and time

What it takes to build.

Materials with the safety surfacing, about (before sales tax, delivery, labor and site work)$6,104

  • Lumber$1,958.11
  • Roofing$536.22
  • Hardware$1,789.51

Shelf prices from Home Depot and Lowe's, read September 30, 2026 to October 27, 2026. Before sales tax, delivery, labor and site work.

Structure at shelf prices
$4,283.84
Safety surfacing (required)
$1,820, playground wood mulch
Structure per sq ft of deck
$35.70
Build time
60 to 88 h
a crew of two, about 4 to 6 working days; a broad reference, not a schedule

Home Depot prices read October 2026. Change the size in the designer and the list reprices with it. Prices differ by store and by week.

Free and paid, side by side

Design it free. Build it from the $29 plan.

Free

On this page and in the designer, no account

  • This design in 3D, and every change you make to it
  • Every planner check, with its rule and source
Cost estimate
About $6,104 in materials, line by line, on this page. See the estimate
Summary PDF
The design, its checks and its materials list on a few pages. A summary, not the build drawings.
Customize this design, free

$29 once

The drawings you build from, for the design you finish. 31 Letter sheets for the 8x10 raised playhouse.

  • Posts and footings dimensioned from one corner, with the hole depth for your frost line
  • The platform framing, the guard with its baluster gap, and the way up with every rise
  • The roof, the playhouse walls, the slide and the swing set when your design has them
  • The cut list, the shopping list with store prices and the build, step by step
Get the $29 plan for this design

You check out in the designer, with this design loaded. If the plan has an error, we fix it or refund you within 30 days. Guarantee terms.

Real sheets from the 31-sheet sample plan for the 8x10 raised playhouse

The sample was printed on an earlier date, so its prices can differ from the estimate above. Your plan prints the same prices as the estimate.

  • Sample sheet 1 of 31: posts and footings

    Posts and footings

  • Sample sheet 2 of 31: guard and access details

    Guard and access details

  • Sample sheet 3 of 31: safety surfacing

    Safety surfacing

  • Sample sheet 4 of 31: connection details

    Connection details

Build phases

From the first cut to the last board in 5 phases.

About 60 to 88 hours for a crew of two, about 4 to 6 working days; a broad reference, not a schedule. Each picture is this design at the end of its phase, drawn by the designer, with that phase's new parts in color.

  1. The Big six-post tree fort after phase 1: footings and posts

    01

    Footings and posts

    Dig below the frost line, pour the footings and set the 6x6 posts on their bases, plumb and square.

  2. The Big six-post tree fort after phase 2: the platform

    02

    The platform

    Fasten the beams to the posts, hang the joists 16 in on center, screw down the decking and add the knee braces in both directions at every post.

  3. The Big six-post tree fort after phase 3: guard

    03

    Guard

    Build the guard posts and the infill so no gap falls between 3-1/2 and 9 in.

  4. The Big six-post tree fort after phase 4: walls and roof

    04

    Walls and roof

    Frame the walls and the roof, then add the siding and the roof panels.

  5. The Big six-post tree fort after phase 5: the way up and the slide

    05

    The way up and the slide

    Build the ladder, the stairs, the net or the climbing wall, and hang the bought slide on its own opening in the guard.

This is the summary. The $29 builder's plan breaks these phases into a build order with the new parts highlighted, a how-to detail and a check at each step.

Questions

Anything else? Write to us or read the questions about all plans.

Questions about the 10x12 plan

About $6,104 in materials at the prices the planner read, before sales tax, delivery, labor and site work. That includes the required safety surfacing under the play area, $1,820 of it. Build time is about 60 to 88 labor hours.

No. It stands on 6 6x6 posts set on their own footings, with knee braces in both directions. Nothing is bolted to a living tree, and a tree nearby is not a support.

The guard is 38 in above the deck, with gaps that stay clear of the 3.5 to 9 in band where a child's head can be trapped. The deck is 6' up.

Yes. Open it in the designer and change the width, the length, the deck height, the roof or the way up. The framing, the checks and the materials list follow every change.

Sizes to compare

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Underneath a deck: a 6x6 post on a concrete footing with a knee brace, joists and beams above, wood chips belowIllustration