Your Jan pre-approval is probably past it's use-by. They have tightened up deposit percentages and other things since. A "pre-approval" is not an iron-clad contract.
If you are happy with the house put in a written offer. If the owner then adds his/her signature that is a contract and you need to put down a small deposit.
Depending on what state you are in you may have a cooling off period but that may mean forfeture of your deposit. After the cooling off period it goes "unconditional" and you are committed subject to any /all of the conditions agreed too. Strictly speaking you can't change your mind and say you can't get finance if it has been offered, nor can you refuse because a building inspection found "cosmetic" defects. You must be sure of what you are doing before you sign.
So you must include "subject to finance" and "subject to satisfactory building inspection" clauses.
If this is the first time find a conveyencing lawyer before you start, you will need one later anyway.
