Build a treehouse lookout tower

Steps 1 -4 

By Wayne Lennox

When I was kid, growing up in the wilds just outside of North Bay, we always had a treehouse – rather rickety affairs that we built ourselves. We spent endless hours in them; it gave us a sense of independence and adventure, elevated as we were above the world (even if it was just a few metres up).

Back then, we didn't think our treehouses might damage living trees and, like all children, we didn't worry much about our own safety. But I designed this project with safety, stability, and tree health in mind. The treehouse is freestanding, so you can build it anywhere, even where there are no suitable trees.

This a big project, but it's fun, especially if you get the kids involved in planning and customizing it. And one of the customized additions they'll love is a lookout tower. You'll find the plans and instructions for the treehouse in the April/May 2005 issue of Cottage Life magazine.

PDF download of tower plans

List of materials

Directions

1) Start by cutting the four tower legs. You'll need to lay out a 1 1/2" x 3 1/2" notch on each of the legs, 66" from the bottom, to accept the 2 x 4 side joists that support the floor and anchor the tower to the roof. I laid all four on edge and clamped them together tightly to make cutting the notches easier and more accurate. Set the depth of your circular saw to 1 1/2"; carefully make the two cuts that define the notches and then make multiple passes between them. Unclamp the 2 x 4s and carefully chisel out the waste. Tip: Chisel out the waste working up from each side of the 2 x 4 and then chisel out the hump in the middle - this will minimize chipping. Work diagonally across the cut.

2) The lookout tower is tied in to the third and fourth rafters from the front (see Figure 2). On the side fascia board, mark a centre line halfway between these rafters. From points 12" on either side of the centre, drop a plumb line down to the deck. This marks the position of the outside edges of the legs; draw layout lines on the deck, square to the face of the building and out to the deck edge. These lines should be 24" apart. Secure two of the legs to the deck floor and the handrail so that they are plumb. I used 3 1/2", #10 deck screws, screwing up through the deck boards into the base of the tower legs and through the legs into the handrail. Remember that the notches face in.

3) Make the anchor board by ripping two edges off a piece of 2 x 8 at 45° (as in Figure 1) and cutting it to 17" long. For the side joists, make a 45° cut across the middle of an 8' 2 x 4, then cut each piece to an overall length of 48". The anchor board sits on the shingled roof, between these two joists. Set each joist in the two tower legs and rest the mitred ends on the shingles. Screw through both joists into the anchor board; a single screw will do for now. Position each joist so that it's level and square to the two tower legs. Fasten the anchor board to the roof with two 2" screws, and the joists to the tower legs. Stand the other two tower legs in place so the joists sit in the notches and the legs are plumb and 24" (outside edge to outside edge) from the first two. Screw the joists to the second set of tower legs and the legs to the treehouse deck.

4) Drill two 5/16" holes through the anchor board and the roof. Cut a piece of 2 x 4 (not pressure-treated) to fit between the rafters, inside the building and opposite the anchor board. Using the two holes you drilled to help position this backer board, screw it to the rafters. Finish drilling the 5/16" holes through the backer board. Bolt with two 5/16" x 5" carriage bolts. To prevent leaks, use a good-quality clear caulking to seal the anchor board and joist ends where they meet the shingles. Drill two 5/16" holes through the end of each joist and about 1/2" into the anchor board (drill at a bit of an angle). Hammer four 5/16" x 5" lag bolts, with washers, into the holes and tighten.

Next:

Steps 5 - 9

Published in the April/May 2005 issue of Cottage Life magazine.

Copyright © 2005 by Cottage Life. All rights reserved. Reproduction of any article, photograph, or artwork, for other than personal use, in whole or in part, without the written permission of the publisher is strictly forbidden.