Expert: Bruce E. Johnson - 9/20/2010

Question
We have a lake house in TX and we are looking at adding about 5 feet across the back along the whole back side of the house (about 57 ft).  The house is on a slab but the back of the house starts to slop down which would mean we would have to have 2-4 feet of concrete and were wondering if we could tie a pier and beam to the slab to reduce the cost?  If we did slab would they just add fill dirt to the slope and then pour the normal amount of concrete?  thanks for your help.  Aaron

Answer
Hi Aaron, honestly? I would build out the area with a concrete block foundation and then fill the foundation with compacted soil and cap it with a concrete slab.  This will keep the ground from washing out during rain storms.  I mean you could do a post and pier foundation in this area but you will need to be extra careful about how you divert water around the house to keep from washing out your pier foundations.   I suppose you could get by with filling the slope and then just capping it with a slab but it would have to be done properly with the right compaction and again proper drainage is the key.  So I guess to sum it up, all of the above are acceptable for a deck or uncovered porch.  For a covered porch you will need a foundation capable of supporting a roof system so I opt for the stem wall concrete foundation capped with a slab.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com