Question
I have a bad smell in my basement that I believe is due to water seepage.  I have been told that the rock beds outside my house need to be redone, and elevated right next to the house.  First, how much of an elevation change do I need from the house to the end of the bed?  Also, some people have told me to use sand instead of dirt to build up the rock bed close to the house. Please help me out.

Answer
The smell is probably due to MOLD that the water seepage has exacerbated.  Things that rot produce methane and other really funky smells, too.  I once move into a house and a few days later the stench was overpowering....A dead cat in the crawlspace.  Ha!  You may also have a sewage leak.

As to the gravel/sand debate, in our area there are very few if any basements.  The usual set-up is a 3/4 basement with a walk-out porch, most often facing south to catch the sun.  Code dictates that any dirt must stay 6 inches lower than any siding that comes down to the footing, be it concrete or brick-work.  Dirt can provide a pathway for termites, which is the principle reason for this restriction.

A typical grading layout calls for a 2 percent slope at five feet from the foundation, or about 1/8th of an inch drop in 5 feet.  If you have a deep basement, and it is surrounded on all sides with earth, you may not have drainage tat can go anywhere that would do you any good, so I have limited suggestions to get rid of a smelly result.  A sump pump, possibly?  For this, you'll need a contractor's help.

Sand will make the water drain faster, but it would have to be substantially deep to do you any good.  The goal is to remove the water to below the elevation of the basement floor, so I抦 guessing that would mean 6 to 8 feet of sand!!

I wish I could be of more help.  ~M