Can loft insulation be put over existing carpet in loft?

No, loft insulation should not be installed directly over existing carpet in a loft. Carpets can trap moisture, which may lead to mold and mildew issues, compromising the effectiveness of the insulation. It is important to ensure that the loft space is properly prepared, typically involving the removal of any flooring materials like carpet, to allow for adequate ventilation and proper insulation installation.