Analysis of different surface treatments applied to different roofing substrates with an emphasis on water absorption

Roofing systems use different materials that require inclinations according to the typology, shapes and dimensions of the roof, but are exposed to different agents of degradation. In Brazil, it is not common to use treatments to reduce the water absorption of roofs in order to guarantee the performance and durability of roofing systems. This research aimed to determine the water absorption index of ceramic, concrete and fiber cement roofing, according to the effectiveness of two different types of treatments, whose function is to reduce water absorption on the roof of the roofing system. The methodology was based on the analysis of the water absorption in the coverings, in a cyclical way of wetting and drying during 12 days. To meet the cyclical effect, a simulation of rainfall was applied to the roofing systems, with exposure for 45 minutes in each type of roofing with and without the use of two different treatments, that is, a silane-siloxane and an acrylic paint at acrylic resin base. The results indicated that the untreated tiles absorb a high percentage of water when compared to the treated coverings. As for the types of coatings, when analyzed with acrylic paint, they obtained a lower water absorption rate when compared to coatings treated with silane-siloxane. It can be concluded that the use of treatments such as water repellent or acrylic paint on ceramic, concrete and fiber cement coverings reduces their permeability and decreases the rate of water absorption, and the acrylic paint obtained better results in relation to water repellent and roofs not treated.