Two bay windows stacked directly on top of each other, joined by a solid black panel between floors, projecting the full height of a two-storey wall in Burlington — this isn’t a configuration most homeowners even know is possible. A single bay window is common enough that most people picture it immediately. Two, stacked into a continuous vertical tower, is a different scale of project entirely, and it changes how the whole facade reads.
Why stacking two bays is a structural project, not a style choice
A bay window on its own projects out from the wall and needs its own support beneath it. Stack a second bay window directly above the first, separated only by the floor line between storeys, and that support requirement compounds: the lower bay has to carry not just its own glass and frame, but the load of an entire second bay window sitting on top of it. This isn’t a project where you install the top unit and the bottom unit separately and hope they line up. The whole assembly has to be planned and built as one continuous structure from the ground floor up, which is why this was completed as a full-frame rebuild rather than a pair of standalone replacements.
What connects the two levels
Between the upper and lower bay sits a solid black aluminum spandrel panel with a diamond-pattern relief, concealing the structural transition between the two storeys. A spandrel panel like this does double duty: it hides the floor structure and header framing that would otherwise be visible as a gap between the two bay units, and it gives the eye a clean, deliberate break between the upper and lower glass rather than an awkward seam. Finished in the same black as the window frames, it reads as part of the window composition rather than a separate patch of trim.
Why black, and why it works on this scale
A black exterior finish on a single bay window is a strong design statement. On a two-storey stacked tower, it becomes the dominant architectural feature of the entire wall. The consistent black across both bays and the connecting spandrel panel unifies what could otherwise read as two separate, competing window projects into one continuous vertical element, set clearly against the light grey brick surrounding it.
Why full-frame replacement mattered here specifically
Because the lower bay carries structural load for the upper one, a retrofit approach working within the existing frame wasn’t an option for this project. The full-frame method that rebuilds an opening down to the studs allowed the framing at both levels, and the header supporting the load transfer between them, to be properly verified and reinforced before either bay window was set in place. On a stacked configuration like this, that structural verification isn’t optional the way it might be on a simpler single-storey bay.
Rebate note: Window replacements like this one may qualify for up to $100 per rough opening under the Home Renovation Savings™ program when you bundle two or more eligible upgrades. ENERGY STAR® certified products are required, and eligibility and approval depend on the current program requirements and administrator, with an energy assessment needed before work begins. See our Ontario window and door grants guide for the details.
If you’re weighing casement versus hung side panels, or double versus triple pane, for a bay window, that decision applies the same way whether you’re doing one bay or two.
Planning a bay window in Burlington? Get a free assessment: request a quote online. Or reach us at hello@trustbuildwindows.com · 1-800-563-1273.
