Tree Houses: Perches for Adventurers, Young and Old

Children love tree houses of all shapes and sizes, whether mere platforms or elaborate arboreal hideaways complete with doors, windows and pulleys to raise and lower picnic baskets.

Tree-house platforms may be attached to strong limbs of a low-branching tree, atop horizontal crossbeams. The design has to suit the tree—a tree with three main branches going off at angles is easiest to work with. Or, in the fashion of structures built around high-branching trees on the White House grounds by Presidents John F. Kennedy and Jimmy Carter, the tree-house platform can be set on freestanding posts.

Safety comes first in designing and building tree houses. Even the most care fully built ones are subject to unusual stress, and their height is a hazard. A tree house made for small children should be within 8 to 10 ft. of the ground, and located within sight of the main dwelling. Guard rails at least 3 ft. high around the sides of any elevated structure are a mandatory safety feature. As an added measure to cushion the shock of an accidental fall, rake the ground beneath the structure free of rocks, then line it with two or three inches of sawdust, tanbark or pine needles.

When attaching a platform frame to a tree, inspect all the branches that you will nail into, to make sure that the tree wood is free from rot, and later check periodically to make sure that high winds or tree growth have not weakened a sup porting brace of the platform. Apply tree- wound paint wherever you cut away branches. Do not skimp on nailing; the nails will not hurt the tree if you spread tree-wound paint around them.

A structure nailed to branches. A typical tree- house platform, attached to a tree that has strong, spreading limbs, rests on 2-by-6 cross- beams nailed between the branches and is braced with 2-by-4s attached to the tree and to the platform frame. The base of the tree house is a framed deck of 1-by-6s laid atop 2-by-6 joists. When building the base, leave one of the end decking boards out so the platform can be hoisted into the tree (Step 2). Guard rails and garden fencing add security.

A small roofed structure sheathed with plywood occupies part of the deck, while a ladder (or a series of cleats nailed to the tree trunk) gives access to a trap door cut in the platform.

Hoisting and Securing the Platform

84 1. Installing crossbeams. Select a site for the platform. With a helper, nail two or three 2-by-6 horizontal crossbeams to the tree at the same height and level. Measure carefully the space the platform will occupy on the crossbeams.

2. Raising the platform. Loop a length of nylon rope around one frame member and use a pulley to hoist the platform up to the crossbeams. With assistance from two helpers on ladders, set the platform onto the crossbeams.

85a 3. Bracing the platform. Working from a ladder with its top rungs resting evenly on a scrap 2-by-4 nailed to a branch, nail at least three diagonal 2-by-4 braces between the underside of the plat form and the tree. To provide reasonably good nailing surfaces for the braces, you may have to trim the ends of the 2-by-4s somewhat until you achieve an appropriate fit. Or you may have to nail a cleat to the tree or the platform and attach the end of the brace to the cleat.

A Deck Built around a Tree

85b A freestanding platform. For trees with high- branching trunks, build an elevated deck, supported by 4-by-4 posts anchored to concrete piers. Make the platform as for the post-and-beam floor and nail headers around the gap in the frame where the tree trunk will be. Attach diagonal braces from the posts to the frame with lag screws. Then nail 1-by-6 flooring boards directly to the joists, leaving a small gap around the tree trunk. Make a guardrail of 2-by-4s and enclose the open space between the rail and the deck with wood or metal fencing.