Two landlords who let substandard properties in Lancing and Southwick have had their appeals against Civil Penalty Notices (CPNs) rejected.
Adur District Council took action against the two buy-to-let investors after they both failed to carry out improvements to unfit rental properties.
They were each fined thousands of pounds, but decided to appeal against their punishments.
Robert Cook rented out a property in Ingleside Crescent in Lancing to private tenants, despite the fact that it had been poorly converted from a garage and had serious fire safety and heating issues.
He was served with demolition orders on two structures, including a summer house, in the garden of the property. But he refused to take down the structures, the council obtained a warrant and carried out the work which will also be charged to the landlord.
The landlord has been told to pay the council £15,000.
He appealed the CPN but it was upheld by the First-tier Tribunal in Havant Justice Centre.
Meanwhile, Dennis Clark, owner of a property in Cross Road in Southwick, also lost his appeal against a fine of £9,350.
He was issued with a CPN after failing to carry out improvements to the property which included fire safety measures and works to complete a shared kitchen.
Cllr Carson Albury, executive member for customer services at Adur District Council, commented: “Civil Penalty Notices are a powerful tool to make it clear to landlords that running or providing substandard living accommodation is not acceptable.
“The proceeds from the fines are also used to support the ongoing work of the Private Sector Housing Team to ensure the safety and quality of rented properties across Adur.”