Firm King Mattress Accessories Adjustable Bed Compatible Mattresses All

Firm mattresses give you the most support of our everyday comfort levels — a solid, stable surface that keeps your spine aligned instead of sinking in. Firm is the go-to for back and stomach sleepers, heavier-weight sleepers who need extra support, and anyone looking for orthopedic, back-friendly comfort; side sleepers or those who like a softer feel may prefer our medium or plush options. Choose from tight-top, foam, euro-top and hybrid builds across Sealy, Serta, Beautyrest, Stearns & Foster, iComfort, Tempur-Pedic, Chirofoam and our own NM line — from budget-friendly models at $59 to premium, with free delivery across Canada. • Feel: firm gives a solid, supportive surface with minimal sink-in • Best for: back and stomach sleepers, heavier-weight sleepers, and orthopedic / back-pain support • Consider softer if you sleep on your side or want more cushioning — see our medium or plush options • Constructions: tight-top (most firm beds), foam, euro-top and hybrid • Brands: Sealy, Serta, Beautyrest, Stearns & Foster, iComfort, Tempur-Pedic, Chirofoam, Springwall & NM • Prices: from $59 (budget) to premium — our widest price range • Want the firmest feel? See our extra-firm mattresses
Everything for a king bed (76″ × 80″) in one place. Shop king mattress protectors, sheet sets, box springs, bed frames, pillows and duvets — note that a king box spring is built as two split halves (each 38″ × 80″) so it's easy to move and fits up tight stairwells. Protectors from HealthGuard and Hush, box springs matched to your mattress brand, plus premium bedding, all with free delivery across Canada. • Fits the king mattress: 76″ × 80″ • Mattress protectors — waterproof, breathable and encasement styles • Sheet sets, duvets and pillows in king sizes • Box springs and foundations (a king ships as two split halves) • Bed frames and bases • Brands: HealthGuard, Restguard, Hush, NM, Leggett & Platt, Sealy, Serta, Beautyrest, Tempur-Pedic & more • Accessories from $13 — free Canada-wide delivery
Not every mattress can bend with an adjustable base — but these can. Every mattress here is built to flex with the head and foot articulation of an adjustable base without damaging the comfort layers, so you can read, relax in Zero-Gravity or elevate your legs with confidence. In fact, over 90% of our mattresses are adjustable-compatible, spanning memory foam, hybrid and pocket-coil constructions from every brand — NM, Sealy, Serta, Beautyrest, Tempur-Pedic, Stearns & Foster and more — at every budget from about $109 to premium. Foam and hybrid models flex most easily, while rigid, thick tight-top innersprings generally don't. Pair any of these with one of our adjustable bases, and every mattress comes with a 365-night sleep trial and free delivery across Canada. • What this means: mattresses built to flex with an adjustable base's head & foot articulation • Over 90% of our mattresses are adjustable-compatible — every brand, every budget ($109+) • Best constructions for adjustable bases: memory foam, hybrid and pocket-coil • What usually won't work: rigid, thick tight-top innersprings that don't bend • Pairs with our adjustable bases (including split-king for independent sides) • Every order: 365-night sleep trial, price-match guarantee & free Canada-wide delivery
Firm King Mattress Accessories Adjustable Bed Compatible Mattresses All
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Upgrade your sleep at National Mattress

Discover a mattress that transforms your sleep into a truly rejuvenating experience. We offer a wide variety of options to suit every sleep style and preference, ensuring a better night's sleep.

Why Choose Us?

  • Variety: From plush to firm, we have options for every body type and sleep style.
  • Quality: Trusted brands and top-notch materials for long-lasting comfort.
  • Sleep Trials & Warranties: Enjoy peace of mind with flexible trials and warranties.
  • Expert Advice: Get personalized recommendations from our sleep specialists.

Mattress Selection Includes

  • Memory Foam: Contours to your body for personalized comfort and pressure relief.
  • Hybrid: Combines responsive springs with foam for balanced support and comfort.
  • Innerspring: Provides firm support, bounce, and cooling airflow.
  • Latex: Hypoallergenic, eco-friendly, and exceptionally comfortable.
  • Adjustable Beds: Customize your sleep position for optimal comfort.
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