Treehouses are great fun for kids, but danger is inherent when you let children play in trees. Inspectors should be aware of a treehouse on a property and warn the owners of their potential hazards.
Power Lines
Despite what we know about power line dangers for residential homes and commercial structures, homeowners sometimes build treehouses near power lines, perhaps due to space constraints. This situation increases the likelihood that children will be electrocuted or burned in a tragic treehouse fire, as it becomes quite easy for them to climb onto the power lines or deliberately touch them with sticks or poles. The wind may also cause the branches to contact the power lines. Some utility companies instruct their workers to flag treehouses that are dangerously close to power lines. Homeowners are then notified and, depending on the company, the tree may be either pruned or removed.
In addition to power lines, treehouses should not be built near or over a cliff, a busy road, or dangerous water features.
Inspection
The Forestry Commission of England offers the following treehouse safety guidelines (their code is in italics):
fall height. The fall height from the treehouse should not be greater than 2 meters unless the structure has good protection against falls, such as railings or other edge protection.
fall zone. The fall zone around the treehouse should be free of any pointed stumps, sharp or large rocks, or dangerous waste, such as sharp metal. Normal vegetation cover, saplings and bushes are not a problem. Wood chips make a good ground cover beneath the treehouse.
access. Access to the treehouse needs to be checked. If a rope or rope ladder is provided, then weight-bearing capacity should be checked by giving the rope a ‘good pull’ with feet firmly on the ground. Wooden ladders are better than rope ladders, which are less stable and pose a strangulation risk.
structure. Structure should be checked to ensure that collapse is not likely. This should be done in a safe manner from outside the structure [while] wearing safety helmet. If ladders are used to access the structure, then working at height regulations should be followed. Also, inspect the tree, as well as neighboring trees, for evidence of weakness, fungus or decay.
snag hazards. Inspect for rough, splintered areas that can be sanded down, and for nails sticking out that may be replaced with screws.
Inspect for loose or rotten boards.
Is there a railing? According to The Black and Decker Complete Guide: Build Your Kids a Treehouse, railings should be at lest 36 inches (0.91 meters) tall with vertical balusters no more than 4 inches (10.2 cm) apart. On treehouses designed for small children, rope or cable should not be used for the balusters. Horizontal balusters are dangerous because children use them to climb.
Advice for Homeowners
Check your homeowners insurance policy or give your agent a call to find out what kind of liability you may face by building a treehouse on your property. It may range from full coverage to no coverage at all, including having your policy's renewal revoked if you build one.
Restrict access to the treehouse, especially if you live in a neighborhood with a lot of children. You may be held responsible if a trespassing child is injured in your treehouse.
Treehouses allow children privacy and freedom, which can be healthy, but keep an eye out for antisocial activities, such as drug use.
If the treehouse borders a neighbor’s house, it may cause a nuisance. Children might need to keep their voices down and be respectful.
Is the treehouse not on your property? Build treehouses on public land at your own risk, as the project might be illegal. Also, the treehouse and children's activity may disrupt the enjoyment of others, or negatively impact nature conservation areas.
Never allow children in the treehouse during inclement weather, especially if you hear thunder.
Construct a pulley and bucket system for hauling items up to reduce the chance of fall or injury.
Restrict the number of children allowed in the treehouse at one time.
Post a list of safety rules for the children to learn, and make sure they follow them.
In summary, treehouses pose some unique risks that can be mitigated with inspection and common sense.