Question
Can tree roots grow under the foundation of my house and come up to compromise the foundation and/or house?  It appears that is what is happening to a 12x12 concrete porch slab that was poured off the back of my house.  There is a popcorn tree growing roots toward that back slab and four cypress trees with MANY knees growing next to and all around the house.  It really scares me that the roots may be pushing up under the house.  I do not know what kind of cypress trees they are.  They are possibly 60 to 80 feet high.  I live in the panhandle of Florida.  Do you have any words of wisdom or advise for me?

Answer
With out seeing the location of the trees and the foundation it would be hard to tell you if the tree is causing problems. Bald cypress dose have a large root system and seeks out moisture popcorm trees are a problem wherever they grow. I would suggest you call the local office of the Florida Division of Forestry  (state agency ) and ask one of their Foresters to come out and take a look. This is a free service. Here is the web link to their contact page.
http://www.fl-dof.com/field_operations/county_foresters/index.html