Why Mulled Units Might Be the Smartest Move for Your Porch
And why Xtend makes it easier than you think.
When designing a porch with large window openings, mulled units can offer a cleaner look, fewer framing interruptions, and wider, more open views. Instead of separating each window with a bulky post, mulled units allow you to connect multiple windows side by side for a smooth, streamlined appearance.
Whether you're laying out a new porch or working through window sizing with your contractor, it’s worth considering how mulled units can simplify the build and maximize the view.
First off—what’s a mulled unit?
At Xtend, a mulled unit is created by joining individual windows together in the field—not at the factory. We ship each window separately for easier handling and installation. Assembly is straightforward, with included color-matching screws and a frame system that’s designed to mull cleanly and securely without extra posts or bulky trim.
What makes Xtend’s mull system different?
No one else does it quite like we do. Most systems require at least a 2-inch post between every window, which means more framing, more material, and more finishing work. Xtend eliminates all of that with a built-in mull system that connects windows directly — no post, no trim, no extra steps.
We get it — contractors are used to doing things a certain way, and any change raises questions. But nearly every installer we’ve talked to has loved this system once they saw it in action. Why? Because it saves time, cuts down on materials, and looks cleaner when it’s done.
📺 Want to see it for yourself? Watch our mull system in action.
How it works:
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No separate post needed – One window uses a special mull frame with a 1" built-in extension that receives the next window’s flange.
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Clean, finished appearance – Inside, the mull looks like a 3" post (1" jamb + 1" extension + 1" jamb). Outside, there’s a subtle flange overlap with matching screws—no cover required.
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No extra cost – A 4-wide mulled unit costs the same as four individual windows. You're simply paying for the total size, not the configuration.
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Ideal sizes – We recommend 36–42" widths per window, but there's no maximum mull width. Just remember: mulls are non-structural and can’t support a roof.
Why it works—for everyone
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Less framing, less trim
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Faster install time
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Wider, uninterrupted views
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Custom sizing—just tell us your total opening
“Contractors love how simple it is. Homeowners love how clean it looks. And everyone appreciates the saved time and money.”
Quick heads-up on safety
If your porch is elevated and fall protection is required, check your local building codes. Xtend windows aren’t structural or rated as safety barriers, so you may need additional railing or guardrail support.
Mulled units are one of those small design decisions that can make a big difference—cleaner lines, fewer materials, and an easier install.
And with Xtend, you get a system that’s simple, smart, and ready to work.
— The Porch Windows Direct Team
📩 Need help planning your project or figuring out sizing?
Click here to request a quote and get expert help.
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