How to Build a Treehouse

Building a treehouse for kids is much easier if you start with a good plan.

First, you’ll need to select a tree that can support the weight of your new treehouse, as well as the added weight of the people that will be in it. Hardwood trees like oak trees, maple trees and hickory trees are all great options as a base. Make sure that your tree isn’t damaged, and that it has nice, deep roots.

Ensure that your tree is high – enough to place your treehouse base at about 6-10 feet up – but not too tall, giving you a nice view while keeping safety in mind.

Once you’ve selected your tree, cut away any small or dead branches so you’ve got a nice, clear area to start building. Measure from the ground to your platform location to get your height, and plan for any walls or railings that you would like to add. This will give you a more accurate idea of the materials you’ll need and the tools you’ll require.

For this treehouse, we’ll be using concrete deck blocks and 4x4-inch posts. Place your concrete deck blocks evenly in a square pattern around the tree. Place your 4x4-inch posts into the blocks, using scrap lumber to hold them in place and level while you connect them.

Next, attach them with 2x8-inch bands, until you have 4 posts connected around the outside with a square. Use a framing nailer and 3-inch framing nails for extra stability.

Now you’ll need to attach the 2x8-inch floor joists to the tree. Pre-drill your boards and the tree to prevent splitting and to make the drilling easier. Use at least 6-inch lag screws to ensure they can support the weight of your treehouse.

Once you’ve got the bolts in, use your impact driver to give them a final tightening. Connect your base to your joists with a spacing of 16 inches from center. Use joist hangers to make the job easier – attaching them with 1-inch galvanized nails. Using galvanized hardware helps ensure it stands up to the elements.

For added structural support, add some angle braces. This will also help to keep everything square.

Use your mitre saw to cut some 4x4-inch lumber to about 2 feet and miter opposite angles on either end. Drill those onto the corners of your floor joists with 3-inch deck screws.

Now you’ll add your deck boards to the platform. This is really where your new treehouse comes together.

Use a nail gun and attach your boards with 2-inch wood nails. Butt them together and nail as you go, eventually covering your whole floor. Remember to measure for the cut-out around the tree in the center and around the posts. Don’t worry about cutting the outside edges to the perfect length – close enough is good for now – you can make a pass along the edges with a circular saw later to make it perfect.

It’s wall framing time! Building walls for your treehouse is just like building a wall for your house.

Measure the length and height you want and make a basic square frame. Using a frame nailer and 3-inch nails, add 2x4-inch vertical studs at 16-inches on the center. Remember to frame out where your doors and windows will go as well.

When you have a wall built, prop it up and attach it to the base with 3-inch wood nails. Keep building and attaching until you’ve got a completes wall around your treehouse.

When attaching the 2x6 ridge beam in the center of your roof, use 2x4-inch lumber to support it while you attach the rafters to the sides of it.

Attach the 2x4-inch rafters at 2 feet on the center using 3-inch nails. Your rafters should reach from the top plate of the walls to the ridge beam, hanging over the edge slightly.

Using 2x4-inch studs, frame your gable walls. The ends will need to be cut at a slight angle to match the angle of your front and back rafters. Once your gable walls are framed, you can move on to installing the siding. You’re almost done!

Cut your siding to size and nail it to the outside of your walls. Attach it to the framing using 3-inch nails.

Install your siding on your gable walls, allowing it to extrude above the angle of the roof. Attach it with 3-inch nails and then use a reciprocating saw to trim it flush with the angle of your roof.

With your siding installed, you’ll now need to cut out any windows and doors that you have planned. Cut outward from the inside using a reciprocating saw. Cutting them out after attaching the siding will ensure a nice, flush cut with your window and door frames.

Now you need to attach the roof to your treehouse. For this, you’ll use plywood sheeting. Start by cutting it to size and then attaching it to your roof joists using 2 3/8-inch framing nails. Leave a 6-inch overhang so that water and debris can be directed away from the sides of your treehouse.

To give you a more finished looking exterior on your treehouse, you can opt to add some trim using either 1x4-inch or 1x6-inch lumber to frame around your doors and windows. This optional step really brings the project together and adds a professional look.

For some added safety, be sure to add a handrail to any open sections of the treehouse decking. These can simply be 2 long boards with smaller lumber added as balusters. Be sure to leave space for your ladder and entrance. Use rail connector brackets to connect your railings to your posts.

Add a ladder to your treehouse by attaching 2x4-inch lumber in a horizontal pattern in between 2 posts. Space them about 7-10 inches apart and attach them with 3-inch deck screws. With your ladder in place, you’re finished!

Your new treehouse is complete! With galvanized hardware and a sturdy construction, you’ll be enjoying it with your family for years to come! For an added touch, you can stain it to any colour you like!