The U.S. Department of Housing and Urban Development stipulates this regarding repairs on FHA properties:
It looks like you have to at least call the lender and ask their opinion on the matter because they have the authority here. HUD itself does not enforce code compliance. However, I imagine the lender has a vendor in the area they would encourage you to go to. In the unlikely event that they do not, I would get some sort of authorization letter from the lender to perform the repairs by the person you wanted to get involved. Just keep in mind that since it's their money on the line, the lender would have a strong propensity to require a "licensed and bonded" entity to perform any work on the property they hold a mortgage for.All repair items required by the appraiser or underwriter must be inspected and the clearance documented. A professionally licensed, bonded, registered engineer, licensed home inspector or appropriately registered/licensed trades person, as applicable, must provide documentation that all deficiencies have been acceptably corrected upon completion of repairs. "As applicable" has been determined to mean any individual who the lender deems to be qualified, which might be the appraiser.