The use of polymeric materials to protect stone started in the 1960's, but studies related to the complex and multiple interactions between stone and polymers have only recently been carried out. In this paper, performance after thermal ageing and simulated solar UV ageing is evaluated. The tests address issues related to the stability and the durability of two fluorinated acrylic copolymers applied to two different Italian marbles, Carrara and San Giuliano. The specimens, treated with two new partially fluorinated acrylic copolymers, 2,2,2-trifluoroethyl methacrylate/methyl acrylate (TFEMA/ MA), and trifluoromethyl-2,2,2-trifluorethyl methacrylate/methyl acrylate (HFIMA I MA), were artificially aged using two different methods: an extended, simulated solar UV ageing of 1000h, and a thermal ageing at about 50°C, the temperature usually reached in the UV chamber, in order to separate the two ageing contributions (photochemical and thermal). After the ageing, tests were implemented that covered most of the testing methodologies suggested by UNI-Normal Italian protocol for evaluation of stone protective coatings, including capillary water absorption, static contact angles and colour variation. Slightly better protective effectiveness was found for the HFIMA/MA before and after the two ageing processes. The important contribution of the thermal component in the diminished shielding efficacy is assessed. -- ICCROM