Why I Patented Our Double Door Construction
Chad Crenshaw
Most companies don’t talk about their patents. I talk about mine constantly.
Not because I’m bragging — but because understanding why it exists will tell you everything about whether a set of iron double doors is built to last or built to fail.
The Problem I Kept Seeing in the Field
Early in my career, I saw a pattern that bothered me.
Beautiful iron double doors — expensive ones — would start showing problems within a few years. Gaps at the center. Doors that wouldn’t close flush. Weather seals that failed. Homeowners frustrated that their $15,000 entry looked tired before the decade was out.
Every time I pulled one apart, I found the same culprit: the meeting rail.
The meeting rail is where the two door panels come together in the center. In a traditional double door, each panel is built as a separate unit, and the stiles (the vertical edge pieces) meet in the middle.
The problem is structural. Those two separate stiles — no matter how well welded — create a seam. And seams are where iron doors fail.
Why the Meeting Rail Is the #1 Failure Point
Here’s what actually happens over time.
A double door set endures thousands of open/close cycles. It handles Texas heat expansion in summer and contraction on cold nights. It absorbs door slams, wind pressure, and the subtle racking that comes with any structure settling.
All of that stress concentrates at one point: the center seam.
When the two separate frame pieces shift even a millimeter relative to each other, you get:
- Visible gaps at the meeting rail
- Door panels that no longer align
- Weatherstripping that can’t maintain a seal
- Water intrusion, which means rust risk
- An entry that looks and operates like a budget door
The industry’s answer was better welds, heavier stiles, more hardware. I kept thinking that was treating the symptom, not the disease.
The Solution: Continuous Tube Construction
I went back to first principles.
The core insight was simple once I saw it: the problem isn’t the weld quality. The problem is having two separate pieces at all.
What if the structural steel tube ran completely unbroken through the entire frame — both panels, the top rail, the bottom — as one continuous system?
That’s what I engineered. And that’s what we patented.
In our double entry door construction, a single steel tube forms the backbone of the frame. It doesn’t stop at the meeting rail and pick up again on the other panel. It runs through.
There’s no seam. There’s no separate piece to shift. The two panels are mechanically unified at the structural level before any glass, metalwork, or finish is applied.
The result is a double door that behaves structurally like a single door — because the skeleton is one piece.
The Double-T Astragal: Part of the System
The continuous tube construction solves the structural problem. The Double-T astragal completes the system.
An astragal is the vertical strip that seals the gap between the two active door panels. Most manufacturers use a standard T-astragal — a single T-profile that bolts to one door and meets the other.
I designed a Double-T astragal specifically for our system.
Instead of one T meeting a flat surface, we have two T-profiles that interlock.
This creates:
- A more positive seal along the entire height of the door
- No single point of contact that can compress and fail
- A mechanically engaged closure that resists wind pressure from both directions
- Better acoustic performance — the interlock absorbs sound rather than just blocking it
The Double-T astragal only works because the continuous tube keeps both panels in precise alignment. If the frame moves, the astragal gaps. Our frame doesn’t move.
What This Means for Your Entry
I want to be direct about what you’re buying when you choose our double entry doors.
You’re not buying a cosmetic upgrade. You’re buying a fundamentally different structural approach.
Competing doors — even expensive ones — are built the old way. Two separate panels, welded stiles at the meeting rail, and eventually the problems that follow.
Our doors start from a patented architecture that eliminates the failure point before the door is ever built.
I’d invite you to compare. Pull up any competitor’s spec sheet and ask them how they handle the meeting rail. Ask if their frame is continuous or joined. Ask what their astragal design is.
Then compare what you find against what we build.
The answers will tell you a lot.
We Own the Manufacturing Process
Here’s something else that matters: we own our factories.
I don’t source from a supplier who builds to a generic spec and ships containers of commodity doors. Every dimension, every material grade, every weld protocol, every finish — we control it all.
That matters for the patent because the continuous tube construction requires precision at every stage. The tube geometry, the bending radius at corners, the way panels are jigged relative to each other before welding — all of it has to be exact.
You can’t achieve that with arms-length manufacturing. You need to own the process.
We do.
If you want to go deeper on how we evaluate iron door quality — from gauge to coating — the Iron & Steel Door Buyer’s Guide covers everything you should be asking before you buy from anyone.
The Bottom Line on Double Doors
If you’re considering iron double doors for your entry, here’s what I want you to remember:
- The meeting rail is where most double doors fail
- Continuous tube construction eliminates that failure point by design
- The Double-T astragal completes the seal and only works because the frame stays true
- We hold the patent because no one else builds this way
This isn’t a marketing position. It’s an engineering solution to a real problem I watched play out in the field for years.
Schedule **your** free consultation and I’ll walk you through exactly how our double door construction compares to anything else you’re considering.