Selling your home depends so much on the current market conditions where you are located. In a hot real estate market where land is at a premium, you may still be able to sell your home with problems as long as it's an “as-is” sale. For an old house, many buyers expect problems and are prepared to address them. This will affect the appraised value if the buyer needs to obtain financing.
A qualified realtor or home advisor can help guide you through the process. In other situations, you might not be able to find buyers unless the foundation safety problems are addressed. In those cases you’ll need to hire a contractor, have the problem fixed, then put the house on the market.