Price with selected options
Square is the workhorse shape of outdoor seating. Patio chairs, bistro sets, deep-seat bases, floor cushions — most of them sit on a square foam core. Here's the catch: almost none of those squares match. One chair takes an 18-inch pad, the next a 22, and the thickness swings from a slim 2-inch bistro pad to a 6-inch deep-seat base. A store-bought cover splits the difference and fits none of them. A custom square cushion cover doesn't split anything — you measure your foam, and we sew to those numbers.
Sun is the real enemy of a square seat cushion. It sits in the open all day, every day, and printed fabrics chalk and gray within a season or two. Both of our Sunbrella fabrics are solution-dyed — the color runs through the fiber, not just across the surface. Add a waterproof square cushion cover in Horizon vinyl for chairs that stay out through rain, and the foam inside stays dry no matter what the week brings.
A replacement square cushion cover is also the cheapest way to make tired seating look new. The foam is usually fine; it's the cover that fades, stains, and splits. Swap the cover, keep the foam, and the whole chair reads as new — one seat or the entire set.
Measuring more than one shape? Shop the full outdoor cushion covers collection and order every seat in one go.
Why Choose Our Custom Square Cushion Covers?
A True Square, to the Quarter Inch
Your 20-inch pad gets a 20-inch cover — not a 19, not a 21. We cut from your seam-to-seam measurements, so the cover sits flat on the chair with no loose fabric pooling at the front edge and no foam bulging at the zipper. Enter the numbers once and every reorder matches.
Corners Built to Take the Strain
Corners are where square covers die. Every time someone sits down, the foam pushes outward into four points of stress. We box the sides to your true thickness and double-stitch each corner seam, so the cover flexes with the foam instead of fighting it.
Full-Sun Duty, Every Day
A square seat cushion doesn't get to hide under an awning. Both fabrics are UV-stable and mold- and mildew-resistant, rated for permanent outdoor exposure. Choose Horizon and the cover is waterproof on top of that — afternoon showers roll off before they reach the foam.
Clean It Where It Sits
No unzipping, no laundry cycle for everyday mess. Horizon wipes down with mild soap and water right on the chair; Canvas takes a soft brush and a hose rinse. Save the deep clean for the end of the season — the cover comes off in one zip when you need it to.
One Set of Measurements, Years of Service
Sunbrella backs both fabrics with a 5-year limited warranty, and the construction is sized for real use — boxed seams, reinforced corners, hardware that doesn't corrode. Buy once for the chair you have, not three times for the chair a big-box cover was guessing at.
Step-by-Step Measuring Guide
Take the foam out of the old cover — measure the bare core, never the stretched fabric.
Measure the width across the front edge, seam-to-seam.
Measure the depth from front to back. On a true square it matches the width; if the two differ, record both exactly as they are.
Measure the thickness at the side edge, bottom seam to top seam.
Check each number twice, to the nearest quarter inch. Your cover is cut from what you enter.
Start with where the cushion sits. A bistro seat next to the grill or a dining chair under a pergola takes spills, sauce, and sunscreen along with the weather — that's Sunbrella Horizon territory. Horizon is a marine-grade vinyl: fully waterproof, backed with a knit layer that stretches in four directions, so it pulls drum-tight over square foam without wrinkling at the corners. Spills wipe off with a damp cloth. It resists cold cracking and meets Cal. TB 117-2013 flame-resistance standards. Warranty coverage runs 5 years limited on strength and color, with 3 more years specifically covering microbial pinking.
For lounging seats where softness wins, go Sunbrella Canvas. It's a woven, 100% solution-dyed acrylic — water-repellent, UV-stable, and breathable, with a fabric hand that feels like upholstery rather than vinyl. Same 5-year limited fabric warranty.
Every square cover is cut as true square panels with boxed sides sewn to the thickness you enter. Corners are double-stitched — the first place a cheap cover splits is the last place ours will. The YKK zipper runs along one side, corrosion-resistant and hidden under a fabric flap so grit and rain stay out of the teeth.
Sewn to your square's exact width, depth, and thickness — no rounding to stock sizes
Choose waterproof Sunbrella Horizon marine-grade vinyl or breathable Sunbrella Canvas
Solution-dyed color that holds in direct sun instead of chalking or fading
Boxed sides cut to your stated thickness, double-stitched at every corner
Replaces worn covers on patio chairs, bistro seats, deep-seat bases, and floor cushions
Corrosion-resistant YKK zipper tucked under a protective fabric flap
5-year limited fabric warranty on both fabric options
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