Expert: Bruce E. Johnson - 10/31/2008

Question
I have a brick home that is 30+ years old.  There is a crawl space below, and I believe the joist are 12-16" apart.  There are concrete or centerblock pillars for support throughout the crawl space.  My living room is about 20' long and 12' wide.  There is apparently a lot of bounce when walking around (TV shakes, pictures shake, etc.), even when my 40lb dog runs around.  I think there is one load bearing wall or beam in the middle of the house (house is around 30-40' wide).  The house is not very big (only 1400 sq ft). I believe the joists are 2x10s.  The living room has a plywood subfloor and carpet, with the rest of the house having hardwoods or ceramic tile.  Is there an inexpensive, but effective way to reduce the floor bounce that I could possibly do without hiring a contractor?  I am trying to put the house on the market and do not want to put a lot more money into it.  What is the most cost effective way to eliminate this problem? I don't have any termite damage (don't know if that matters).  Any suggestions you would have would be greatly appreciated.

Answer
Hi Curtis, is it possible that the beam holding up the floor joists hasn't shifted or settled?   Maybe just shimming up the joists on the beam will help. Also your joists should have a row of bridging blocks mid span on both sides of your beam and one row over the top of the beam.  If not then adding them would help.  Bridging blocks are either solid blocks the same material size as that of the joist. They are inserted and nailed between each joist in a continuous line.  These help keep the joists from moving around.  Sometimes metal or wood X braces are used instead of the bridging blocks.

If all of the above are in good shape you might consider adding another beam on each side of the existing beam.  This isn't too hard to do.  You can buy precast footings at Home Depot or most other building supply stores.  These footings should be laid out in a straight line mid span of the joists.  A 4x6 beam should suffice and you can space your footing pads at 8' apart with a 4x4 up to the beam.  I like to cut my posts as tight as possible and jam them into place with a small sledge hammer.  If you cut your posts too short you can wedge them up tight with shims after the fact.  

I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com