If you’re building a custom home in Charlotte, there’s a building science conversation you need to have with your builder before the first wall goes up: rainscreens.
What Is a Rainscreen?
A rainscreen is a drainage gap between your exterior cladding (siding, stone, brick) and the weather-resistant barrier behind it. It creates an air cavity that allows moisture to drain and dry rather than getting trapped inside your wall assembly.
It sounds simple because it is. But the difference it makes in long-term performance is enormous — especially in Charlotte’s climate where we get 43 inches of rain annually and humidity regularly exceeds 80%.
Why Charlotte Homes Need Rainscreens
Charlotte sits in Climate Zone 3A — hot and humid. That means your walls face a dual challenge: rain hitting the outside and moisture vapor trying to move through the assembly from both directions depending on the season. In summer, humid air drives moisture inward toward your air-conditioned interior. In winter, interior moisture pushes outward.
Without a drainage gap, any moisture that gets past your cladding — and it will — has nowhere to go. It sits against your sheathing, promotes mold growth, rots framing, and degrades insulation performance. We’ve seen homes less than 10 years old with significant wall damage because this single detail was skipped.
The Standard We Hold
Every Royal Building Group home gets a proper rainscreen assembly. Not because code requires it — North Carolina’s residential code is still based on 2009 standards and doesn’t mandate rainscreens — but because the building science is clear.
We use drainage mat systems behind all cladding types: fiber cement, natural stone, brick, and stucco. The system creates a minimum 1/4” gap that allows bulk water drainage and promotes drying through ventilation. It’s a small cost addition that prevents catastrophic long-term failures.
What to Ask Your Builder
If you’re interviewing builders, ask these questions:
- Do you install rainscreen systems behind all cladding types?
- What drainage gap do you maintain?
- How do you detail flashing at transitions (windows, rooflines, penetrations)?
- What weather-resistant barrier do you use, and is it vapor-permeable?
If the answer to the first question is no — or if they don’t know what you’re asking about — that tells you something important about their approach to building science.
Building Beyond Code
Code is a floor, not a ceiling. It represents the minimum standard a building must meet to be occupied legally. At Royal Building Group, we study and follow the latest building science research and hold our trade partners to those standards. Your home is too important to build to the minimum.