Insulation and drywall organisation G Man Insulation has been ordered to pay $272,253 (£208,413.76) in back wages, damages and penalties.
The fines are the result of an investigation by the US Department of Labor Wage and Hour Division (WHD), which uncovered violations of the Fair Labor Standards Act (FLSA) affecting 39 employees.
WHD investigators found the organisation, based in Nampa, Idaho, paid workers either by the hour or by the day, and that in both cases it had failed to pay overtime when employees worked more than 40 hours in a working week.
The investigation also found that G Man Insulation paid employees in cash for overtime hours, at the rate for normal working hours, and that this overtime was then not recorded in the employer's payroll records.
The employer will pay $126,262 (£96,655.45) in back wages and an equal amount in liquidated damages to resolve the violations. G Man Insulation has also been assessed for $19,728 (£15,102.08) in civil penalties.
Thomas Silva, WHD district director, said: "Ensuring that construction workers are paid the wages they have earned will level the playing field in the industry. Violations and penalties like these can be avoided.
"We encourage all employers to make use of the many tools we offer to help them understand their responsibilities, and to reach out to us directly, and confidentially, with any questions they may have about how to comply with the law."
G Man Insulation was unavailable for comment at the time of publication.
