Unfortunately, HUD has no authority to repair the defect or compensate the homebuyer for any problems. On an existing home, FHA does not warrant the condition of the property. The purpose of an FHA appraisal is to estimate the value of the property for insurance purposes.
FHA may take disciplinary action against an appraiser in the event that the appraiser committed a serious mistake during the appraisal process.
You should contact your Lender and/or the real estate agent to discuss your concerns, or discuss your situation with an attorney.
HUD Policy Determination