How To Build A Treehouse For Kids

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Tree houses are magical places for children. They can imagine them to be a pirate ship, hidden castle, clubhouse, or a special and secure place for sleepovers with their friends.

You'll want to keep children's safety in mind when planning the tree house. Getting started is easy if you sketch out a plan on paper before construction. Get the kids involved early in planning. Most children have vivid imaginations and are a great source of inspiration.

Next, make a list of the lumber, hardware, and tools needed for the project. As with any home construction project, talk to your local building department about building regulations which may affect your tree house.

Selecting The Right Tree And Location

Take a walk around your property and decide where to build the tree house. Hardwood trees such as oaks or maples make the strongest trees, but softwood trees will work nearly as well. Select a tree that is at least 24 inches in diameter for a freestanding tree house. If the tree house will be partially supported by posts, an 18 inch diameter trunk will work too. If smaller children are going to play in the tree house, it may be safer to build it closer to the ground. An elevated platform of 5 feet will seem quite high to a child.

• Tree houses can be attached to a tree trunk and freestanding

• Tree houses can be partially supported by posts

• Build closer to the ground for smaller children

Ready for Planting Finished Product


Foundation And Posts

For most tree houses you'll want to attach the platform to the tree trunk. Galvanized lag bolts are the preferred method. Choose lag bolts of sufficient length to penetrate six inches into the trunk at several locations. If building a supported platform with two or four posts, you will want to dig 24 inch holes for the posts and fill with concrete to anchor the posts.

• Use four by four inch lumber for the supporting posts

• Anchor the posts in concrete or attach them using galvanized post brackets

• Use galvanized lag bolts or other weather resistant hardware

Building The Deck Platform

To build a tree house that is safe and will last throughout the winters, use pressure treated lumber for the exposed portions like floor joists and posts. Selecting two by six lumber will provide enough support for most platforms of eight or 10 feet in length. Build the outside edges of the platform first and square with corner cleats. Hoist into place, level and attach to the tree trunk and posts if needed. Once secured, attach the additional floor joists at 16 inch intervals. These can be nailed, screwed or secured with joist hangers which are galvanized metal and easy to use. Finish the platform and cover with one by six inch lumber. If the platform is to be exposed, leave a one half inch gap between boards for water to run off during rainy seasons.

• Use two by six inch lumber for floor joists

• Choose galvanized screws and brackets

• leave a gap in floorboards for rainwater

Railings And Stairs

All tree houses should have railings for safety. Plan on adding railings at least 30 inches high. The railings should be securely bolted to the floor joists. Use two by four inch lumber for the uprights and a two by six inch lumber for the top cap. Add two by two inch pickets spaced at six inch intervals to prevent children from squeezing through the railing. One inch lumber can also be substituted for the railing pickets. But keep the openings between them at six inches or less for safety.

Stairs can be as simple as a vertical ladder or an inclined staircase. Use two by six inch lumber for the sides and either two by two inch lumber for a ladder or one by 10 inch lumber for stair treads. If the stairs rest on the ground, add a couple of bricks as a base to keep the bottom edge off the dirt or grass and prevent rot.

• Securely bolt all railings to the platform

• Use two inch lumber for railings

• Keep railing pickets close together for safety

Going Beyond The Basics

Your tree house can be as simple as a platform with railings or as elaborate as a pirate ship or castle. Pirate ship cannons can be as easy as several lengths of black ABS drain pipe. Flag poles can be made from round dowel or an old broom handle.

Adding simple walls and a roof can make the tree house into an imaginary castle or fort.

The only limit is your imagination. Have the kids help with establishing a theme and they will have a lifetime of fun, excitement and imagination.

Tools You'll Need

Having the correct tools at hand will keep your project moving smoother. Gather tools, wood, hardware, and other building materials together at the beginning of the project.

• Your building plan or sketch and a list of lumber needed

• Portable skill saw or table saw

Electric drill motor and drill bits

• Open end or box wrenches or two adjustable wrenches


• 12 foot tape measure

• Framing square

• Lumber

• Lag bolts, nails and metal brackets

• Post hole digger

Shovel and hoe for mixing concrete

• Quick-set concrete

Last Updated: August 31, 2011
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About Bill Washburn William "Bill" Washburn has a BA in advertising from the Art Center College of Design and has taught at the University of Southern California and Northrup University. Writing from a well-connected studio in the rural foothills of the west coast, he is a frequent speaker at local art associations and has published numerous articles discussing periods of art history and the fundamentals of drawing and painting. William is a master gardener who grows his own culinary herbs, organic heirloom vegetables and a variety of fruits. He writes frequently about his gardening experiences on his website Pioneer Dad. He is an accomplished advertising writer, fine art painter, and art director with more than 20 years' experience. 

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