Couch Cover DIY: Keeping the Couch Safe from Dog and Cat Nails

Couch Cover DIY: Keeping the Couch Safe from Dog and Cat Nails
When my cats and I moved from San Francisco to nearby Emeryville 15 months ago, my boyfriend, who had never before had a pet, got to experience the displeasure of seeing his belongings through the eyes of my two cats. They decided, for example, that a pair of tall paper lanterns were for climbing. His potted dragon tree was for eating. A coir mat by the door, for scratching. And the L-shaped leather couch in the open-plan living room? A raised track for chasing each other at high speeds. 
Things have since mellowed around here: The lamps are gone, the dragon tree now lives in the (cat-free) bedroom, and scratching the coir mat is allowed. But to keep the couch safe, I draped two drop cloths over the frame and hoped for the best. 
A long while later, I finally got around to solving the problem: By sewing a fitted cover—with hidden scratch-proof pad—for the back and arm of the couch.

Above: The finished couch cover runs along the back and arm of the L-shaped couch. 
Faunamade Black Cat on Couch Cover DIY
Above: My cat, Reine, perched on the arm of the sofa. 
Faunamade Cat and Dog Couch Cover DIY
Above: Since the cover will take a beating, I chose a durable fabric in a dirt-resistant color: Robert Kaufman Big Sur Canvas in Taupe. It's 100% cotton and weighs about 10 ounces per square yard. 
(Curious to see the whole kitchen in the background? See Before & After: A Remodelista Editor's Dated California Kitchen Gets a Refresh.)

Above: The cover extends down about seven inches on both the inside and outside of the couch. 
Above: I sampled a number of fabrics and realized my cats' nails would sink through any of them. So I lined the center panel with two layers of recycled poly felt: I stitched them together, then tacked the felt pad to the canvas with a few stitches roughly every 18 inches.

Above: For the corner where the arm meets the back, I simply laid the back panel on top of the arm panel at 90 degrees and stitched them together. 
Above: Should I take a nap in my Faunamade Basket Bed or chase Minou across the back of the couch?