Corrugated metal (and its cousin, “Box Rib”) is the darling of the modern tiny house movement. It’s lightweight, durable, fire-resistant, and relatively affordable.
But once you buy the panels, you face a major design decision: Which way do the ribs run?
Orienting your panels vertically or horizontally isn’t just an aesthetic choice—it fundamentally changes how your house handles water and how you frame your walls.
Option A: Vertical Orientation (The Classic Barn Look)
This is the most common installation method for agricultural and commercial buildings, and for good reason.
1. Water Shedding: Superior
- Gravity is your friend. When rain hits vertical panels, it channels instantly down the troughs to the ground.
- Self-Cleaning: Dirt, pollen, and leaves wash away easily because there are no horizontal ridges to trap them.
- Leak Proofing: The seams are vertical. Unless you have wind driving rain sideways at 60 MPH, water naturally flows parallel to the seam, not into it.
2. Aesthetic Impact
- Height Illusion: Vertical lines draw the eye upward. On a tiny house that is often short (to stay road legal), vertical siding makes the structure feel taller and more spacious.
3. Installation & Framing
- Furring Strips: To install vertical panels, your furring strips (strapping) must run horizontally.
- The Catch: Horizontal furring strips can trap water against the house wrap. You must install them with drainage gaps or use a product like Cor-A-Vent to allow water to drain behind the strips.
Option B: Horizontal Orientation (The Modern Industrial)
Running corrugated metal horizontally creates a sleek, contemporary look that mimics high-end architectural lap siding, but with an industrial edge.
1. Water Shedding: The Risk Factor
- The “Shelf” Effect: Every rib acts as a tiny shelf. Water, snow, and dust sit on top of the ribs rather than running off immediately.
- The Lap Joint: The horizontal seams where panels overlap are vulnerable. Water can wick up into the joint (capillary action) or be driven in by wind. You must be meticulous with your overlap sealing (butyl tape is mandatory here).
- Corner Flashing: Requires complex “box” corners which can be difficult for DIYers to fabricate cleanly.
2. Aesthetic Impact
- Length Illusion: Horizontal lines draw the eye side-to-side. This makes a 20-foot tiny house look longer and more grounded.
- Modern Vibe: It looks less like a “barn” and more like a modern shipping container conversion or architectural studio.
3. Installation & Framing
- Furring Strips: To install horizontal panels, your furring strips run vertically (aligned with the studs).
- The Benefit: Vertical furring strips are fantastic for drainage. Any water that gets behind the siding runs straight down the channel between strips. No special venting products needed.
The Structural Reality: Bracing
Metal siding provides very little “shear” strength (resistance to racking/twisting).
- Vertical: Slightly better at resisting uplift loads.
- Horizontal: Requires more frequent fastening to prevent sagging or “oil canning” between studs.
The Verdict for Tiny Houses
Choose Vertical If:
- You are a first-time DIYer (easier flashing/corners).
- You live in a high-precipitation or snowy area (best drainage).
- You want a low-maintenance exterior that self-cleans.
Choose Horizontal If:
- You are chasing a specific modern aesthetic.
- You are confident in your waterproofing/flashing skills.
- You are using a thicker gauge metal (24ga or 22ga) to resist waviness.
Pro Tip: Can’t decide? Mix them. A popular tiny house trend is to use horizontal wood siding on the lower half (warmth) and vertical metal on the upper half (durability).