Michelle, Dave is correct. I am going thru same problem & had contractors over to do estimates. One was kindly enough to suggest I dig around problem area to locate problem whereby if problem too big for hydralic cement + tar or do it yourself he would come out & seal. Seems to be the biggest cost is diggig which if you have a couch potatoe or friend that can help out you can save some money. Case in point another guy that came out quoted me $1200.00 to which by the amount of time he spent looking over the place I figure it was a small job for the price.