Bed Frame King Split Marshall® Boxsprings Handcrafted Foundations Mattresses for Standard Bed Frames Mattress Accessories

A king box spring is almost always built as two split halves (each 38″ × 80″ — the same footprint as a Twin XL) that sit side by side under your king mattress (76″ × 80″). The split design makes a large king foundation easy to deliver, carry up stairs and set up, and it's exactly what a split-king adjustable base needs so each side can raise and lower independently. Shop split king box springs and foundations matched to Sealy, Serta, Beautyrest, Simmons, Stearns & Foster and more — free delivery across Canada. • What it is: a king box spring built as two 38″ × 80″ halves (each a Twin XL footprint) • Together they support a standard king mattress (76″ × 80″) • Easier to deliver and carry up stairs than a one-piece foundation • Required for split-king adjustable bases (each side adjusts independently) • Brands: Sealy, Serta, Beautyrest, Simmons, Stearns & Foster, Springwall, Galaxy & NM • From $176 — free Canada-wide delivery
Marshall® boxsprings and foundations are handcrafted in Canada to give your mattress a stable, supportive base. Choose a low-profile 6 inch, high-profile 9 inch or slim 2 inch posture board to set your ideal bed height, with split options for larger sizes. Built to last and backed by a 10-year warranty with free next-day delivery in Toronto.
These mattresses are built for a standard bed frame, box spring or platform bed rather than an adjustable base — solid, no-flex support for a classic setup. Shopping by feel or build instead? Browse by comfort (plush, medium, firm) or by type (memory foam, hybrid, pocket coil, traditional). Using an adjustable base? See our adjustable-bed-compatible mattresses. Every order includes a 365-night sleep trial and free delivery across Canada.

Complete your sleep setup with pillows, toppers, protectors, and more. These mattress accessories enhance comfort and extend mattress life.

Bed Frame King Split Marshall® Boxsprings Handcrafted Foundations Mattresses for Standard Bed Frames Accessories

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