Why is an acrylic base coat applied over bituminous membranes?

The application of an acrylic base coat over bituminous membranes primarily serves to seal the surface and prevent discoloration caused by asphalt bleed-through. Bituminous membranes, while effective for waterproofing, can sometimes allow the natural oils and asphalt materials to migrate to the surface, leading to an unsightly appearance and potential aesthetic issues. The acrylic base coat acts as a barrier, effectively preventing this bleed-through, thus maintaining the roof's visual quality over time. This sealing function is crucial in ensuring the longevity and integrity of the roof while also providing a uniform surface for subsequent coatings. The addition of an acrylic base coat also enhances the overall performance of the roofing system by increasing its durability against environmental elements.