I recently tried making a modular sofa from an old mattress, and it turned out to be one of the most rewarding DIY projects I've done for my small apartment. The process began with repurposing a 1.5×2 meter mattress that was just taking up space. Cutting it into two halves allowed me to create comfortable seat cushions, which I then wrapped with foam to avoid sitting directly on the springs—a step I found crucial for comfort. Using spray adhesive to securely attach the foam was straightforward, and sewing the sofa covers was surprisingly enjoyable. Taking precise measurements ensures the covers fit snugly, and adding a zipper makes cleaning hassle-free. For extra durability and style, I stitched decorative piping along the edges, which also reinforced the seams. One of the best parts was integrating a sofa frame made from stainless steel tubes, providing sturdy support while keeping the design lightweight and modern. This modular sofa-bed is perfect for small living rooms or studios because it can be folded and rearranged according to the occasion—whether as a cozy sofa for entertaining guests or a comfortable bed for overnight stays. This upcycling project cost around 600 yuan, making it highly affordable compared to buying new furniture. It not only helped reduce waste but also added a personal touch to my home decor. If you have unused mattresses lying around, this DIY is definitely worth trying—it's a fantastic way to combine creativity, functionality, and sustainability in your living space.