Question
My next door neighbor has a gorgeous huge Live Oak Tree, however the roots from the tree have grown into my yard and are now starting to go under my house as well as ruining the yard,thus cracking the brick foundation, what can I do? This one root is is about 8 inches round and at least 7-9 feet long.

Answer
You can install a root barrier along the house and this will keep the roots from going under the house. This means digging trench along the house and installing a barrier. Here is a web link to these barriers. http://www.4specs.com/s/32/32-9452.html

You did not say how far away the tree was--the roots further from the trunk will be smaller and not a much a problem as the ones close to the trunk. The ones growing above the soil surface can be covered with sand but try not to use more than 3 inch deep in one year.

You can cut up to 25-30% of the trees root system without seriously damaging the tree. So cutting a few  large roots should not effect the tree.