How to Build a Porch & Deck Around Trees
- 1). Estimate how much more the tree is likely to grow. This will help you plan the amount of room you will leave around the tree in the decking. If you aren't sure how much more the tree will grow, you can check with your local agricultural extension agent, nursery or tree surgeon.
- 2). Prepare the soil so that the tree will continue to get adequate moisture even if it is covered by the deck. To do this, take a piece of rebar and poke holes in the ground around the tree's root system. Pour pea gravel into the holes to keep them open and to give rainwater a place to percolate into the ground. This will help to train the roots to grow downward where the water is, rather than outward into the footings of your deck.
- 3). Map out the tree's surface root system so that you know where all the major roots are. Then design your deck or porch so that the footings are not close to these roots. Design the actual structure of the decking so that the decking around the trunk can be removed if the tree grows larger than the space allowed by the decking.
- 4). Set your footings and piers by digging holes into the ground that are wide enough to hold the footing form and below the frost line. You may have to cut into a few minor roots, to install footings, but try to avoid injuring even minor roots whenever possible. Fill the footing holes with concrete and set the joists onto the top of these footings.
- 5). Attach your decking beams to the joists so that they run perpendicular to your house except in the area around the tree. Run double joists parallel to the house on either side of the tree. Then run beams perpendicular to the tree. Make the beams attach to these joists so that the tree is surrounded by the beams and joists. Install diagonal supports at the corners between the beams and the tree. This way the weight is distributed evenly around the tree with no need for footings directly around the tree.
- 6). Attach the trim to the decking, leaving space for rainwater to run off between the boards and reach the tree's roots.
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