Dura-Build is the best exterior primer to smooth uneven surfaces, bridges and fill cracks andpermanently resists peeling paint and cracking surfaces. Mad Dog quality at national brand pricing. Use on all surfaces for new andweathered projects. Dura-Build helps last up to 20 years. Mad Dog Dura-Build fills in and levels uneven surfaces for a more uniformlook. High build formula fills and smooths rough and cracking areas. Applies at up to 30 mils wet, extends the life of top-coats for up to 20 years, and reduces prep time by up to 20%. Use on wood, metal, masonry and other substrates.