It's a tempting idea: why buy expensive outdoor benches when that perfectly good indoor sofa or wooden chair is just sitting there? The short answer is: you can try, but you likely shouldn't. While treating indoor furniture for outdoor use is possible, it's often a temporary and high-maintenance solution compared to investing in proper outdoor-rated pieces.
Indoor furniture is built for a stable, climate-controlled environment. Its materials—untreated woods, certain metals, fabrics, and composites—are not designed to withstand moisture, UV rays, and temperature extremes. Applying a sealant, stain, or outdoor fabric spray can offer a layer of protection. For example, treating a solid wood table with a high-quality marine-grade varnish might buy it a season or two. However, this protection degrades quickly. Joints will swell and contract, leading to warping. Fabrics will mildew. Fasteners will rust. The maintenance required to keep it functional becomes a constant chore.
True outdoor furniture is engineered differently. It uses materials like powder-coated aluminum, teak, acacia, or all-weather wicker. These are chosen for their inherent resistance to rot, rust, and fading. Their construction often includes drainage holes and UV-stabilized fibers. The investment pays off in longevity and safety; a properly built outdoor bench won't collapse after a rainy season.
Verdict: For a temporary, seasonal solution with a piece you're willing to monitor and re-treat frequently, using treated indoor furniture outdoors is a calculated risk. For a durable, safe, and ultimately more economical choice that will last for years with minimal care, sticking to properly constructed outdoor benches and furniture is the unequivocally smarter decision.