Fiber Cement Siding
Water Infiltration: Water can soak through fiber cement siding and especially leak around it, particularly at corners and joints. Fiber cement is also nailed tightly to the wall, leaving the water no way to get out. Caulking may block water infiltration on new installations, but the best long-term protection is a secondary weather barrier.
Water Management Solution: Install a drainage wrap to move the water to the base of the wall. A drainage mat with thicker drainage channels is even more effective. Both approaches allow air movement in the space between the wrap and the siding to help facilitate drying.
RainDrop® Building Wrap is an ideal secondary weather barrier for fiber cement siding. It drains water and maintains space for air movement. Unlike embossed or “crinkled” drainage wraps, the drainage channels do not crush when the siding is nailed tight.
DC14 Drainage Mat, with drainage channels on both sides, provides even greater drainage and air movement behind fiber cement siding. The best practice, when windows are to be flashed, is to install a layer of GreenGuard wrap as a secondary weather barrier before installing DC14.