Like I said estimates are free. If that deck is causing a problem and you cant get under it, take that money and build a roof over it, get your gutters fixed remember your putting 2000sq foot of water in a 4 inch holes, if water is running to you do something to divert it. This can be done wirh landscaping, not just mulch. Consider your house is your boat, if its leaking do you add a bilge pump, when leak gets worse, bigger pump. No try something outside first.