Before calling any waterproofing service providers, it is advisable that you contact the Better Business Bureau, and research each company you are considering. Referrals from friends or family can be extremely valuable.
Call two or three companies for consultations to ensure that you are getting the best price and only the waterproofing services you need. You can also browse to http://mistermembrane.com.au/services/ to hire the professionals for waterproofing services in Sydney.
During the inspection, be prepared with pertinent questions, depending on the waterproofing services recommended. For example, if they recommend sealing the basement walls, be sure to find out if they intend to repair cracks in the foundation first.
If they are recommending outdoor repair, be sure to ask what kind of excavation plan they will follow. Using mini excavation equipment and hand digging is acceptable, however, commercial excavation equipment for a residential waterproofing project is not appropriate.
Finally, ask about their warranty. A reputable company should offer a "no-water" warranty, meaning that you should find no water leaking into the foundation for any reason. This warranty should be void of service fees and exceptions.
Before signing with a particular contractor, be sure there is no confusion about the services he feels are necessary, why he believes they are necessary and what the costs will be.
The contractor will tell you after his/her inspection what kind of project needs to be completed. This could be as simple as repairing some cracks in the foundation. He could see a need to add a sealant on the inside of your basement walls.