FHA does not "approve" homes. If you are trying to purchase a primary residence using FHA, the "approval" is part of the financing process. Technically, you could say that any home that is livable would be OK with FHA. During the mortgage approval process, an appraiser will visit the home and inspect it to determine value, and also livability. If the appraiser finds that there are problems that would prevent you from occupying the home at closing, he will not the appraisal. This becomes a "lender required repair," which means that in order for the financing to go through, the seller has to correct the problem. Some examples would be a leaking roof, an a/c system that is not working, severe termite damage, or a non-working hot water heater. If the seller refuses to make the repairs, then the loan is denied, and the financing falls through (and you get out of the contract).
The only type of building that FHA per-approves are condos. In this case, the entire condo complex must be approved by FHA in order for any single unit to qualify for financing. You can look for FHA approved condos on the HUD website, at HUD.gov.
Very important: you can only use FHA financing for a primary residence! If you are buying for investment, FHA financing is NOT available!