Hardie Fiber Cement Siding Installation
This custom house is getting siding put on now. We’ve got some James Hardie fiber cement siding going on. Today, I want to walk you around and show you some details we’re doing to make it watertight and ensure the siding looks nice.
Choosing the Right Hardie Siding for Your Climate
This custom home is getting James Hardie fiber cement siding with a 5-inch reveal. It is from the HZ series, so you need to make sure you’re choosing the right one for your region.
- HZ5 is for colder climates.
- HZ10 is for warmer, humid climates.
The 5-inch reveal means that when you measure from the bottom edge of one siding board to the bottom of the next, you’ll see 5 inches.
How We Waterproof Electrical Outlets in Siding
For electrical boxes, the first step is installing the box with a full-perimeter flange. I did another video on this that you can check out, but here’s the breakdown:
The box gets taped to the ZIP sheathing. After that, we cut and installed the head flashing, bending it to direct water away, and then taped the flashing to the ZIP to ensure water sheds around the box. Once this is done, the mounting block slides under the head flashing and is secured to the wall.
A rain screen is also installed over the head flashing for added protection.
This method fully waterproofs the outlet, preventing water from ever reaching the framing.
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Head Flashing for Windows – No Caulking Needed
At the top of the windows, we use 24-gauge galvanized steel head flashing, pre-painted white and bent at 115 degrees.
Water runs behind the siding, hits the angled flashing, and drains away naturally. We don’t caulk this joint; water is designed to flow out independently. We bend the metal around the edges, ensuring a clean finish instead of leaving exposed cut edges.
We skipped a drip ledge here because we wanted a clean look, and the Hardie siding makes it unnecessary. It’s a solid, durable setup, and since this is under a porch, it’s not a big concern.
How We Handle Butt Joints Without Caulk
For butt joints (where two siding boards meet), Hardie recommends moderate contact. If both edges are factory primed, we butt them together. If the edges are cut on-site, we prime them using Kilz Shellac-based primer before installation.
Instead of caulking the joint, we use Tamlyn PF6 flashing behind the siding. Doing so provides a protective barrier, eliminates caulk, and allows for natural expansion and contraction while preventing cracks and maintenance issues.
Rain Screen & Bug Protection
The rain screen system runs from the bottom of the wall to the soffit, leaving a small gap at the top for airflow. It prevents moisture buildup behind the Hardie siding.
We install an 8-inch fiberglass bug screen along the bottom to keep bugs out, rolling it over the rain screen. This method blocks insects, allows water to drain, and maintains proper ventilation.
This setup is especially important at roof-to-wall transitions, porch areas, and dormers, where ventilation and drainage are critical.
Beam & Trim Details for a Clean Finish
We tighten the fiber cement siding at beam intersections for a modern, trim-free look. The siding is cut tight to the beam, eliminating the need for extra trim. The corner spacing is adequately maintained, making caulking easier as we go.
We also take steps to prevent air hoses and cords from damaging the trim by securing sill sealer and ZIP tape at key impact points.
Final Thoughts
This method ensures a waterproof, durable, and clean Hardie fiber cement siding installation. If you’d like more information about custom home building or ADUs, visit freemansconstruction.com.
Take a look at our comprehensive collection of similar videos on our YouTube channel, The Real Property Show.
