Trees- Nature's lungs and home wreckers

posted Oct 15, 2015, 11:39 AM by Amy Stone
We all want trees around our home or commercial property.  They provide shade and are interesting to look at.  However, as far as your foundation is concerned, trees nearby are dangerous.  For our case, nearby can be defined as: within 1 times the mature height of the tree.

Trees are giant sponges.  As a tree grows and matures, it removes moisture from the soil around the roots.  If the tree is mature, it has sucked all the water out of the soil contained in the root ball.  

To put a foundation near an existing tree, we usually recommend cutting roots and installing a root barrier between the foundation and the tree.  Often this is a grade beam several feet deeper than required by design.  If the foundation is close to the tree, and many roots are cut, the tree may not survive.  If the tree dies after you have built the foundation, then the moisture removal will stop and the soil will re-hydrate, causing swelling.  

If you remove the tree and stump before construction, then the tree will stop sucking the water out of the soil.  This means that the soil will re-hydrate and probably swell.  This can be mitigated during construction by digging out the stump and moisture conditioning and compacting the soil that is used to fill the hole.  

Some get around the whole situation by installing pier and beam foundations which are easier to re-level as the tree goes through it's life cycle.  

Typically, the best solution depends on the size of your building and how closely construction will be monitored.  Of course, how much you want that beautiful home wrecker counts, too!

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