129 Commonwealth Avenue Welcome to this exceptional custom-expanded home in Massapequa offering luxury living, premium upgrades, and incredible attention to detail throughout. This stunning residence features 4 spacious bedrooms, 3.5 bathrooms, a fully finished basement, and a detached 2-car garage designed for both everyday living and high-end functionality. In addition to the bedrooms, the home also includes a private ground-level office that can easily be converted into a 5th bedroom, guest suite, or flexible living space. Inside, you'll find beautifully designed living spaces highlighted by a stunning 16x21 family room featuring a wood-burning fireplace, creating the perfect gathering space for relaxing or entertaining. The home is complemented by central air conditioning and forced hot air heating with 2-zone climate control, a whole-house humidifier, UV air purification system, and smart-home infrastructure throughout. The chef's kitchen is outfitted with premium appliances including a Wolf range and built-in Miele coffee system, offering both luxury and functionality. The expansive primary suite features radiant heated floors in the spa-inspired bathroom, while spray-foam insulation throughout enhances year-round comfort and energy efficiency. Additional upgrades include a fully automatic whole-house Generac natural gas generator, 200-amp electric service with multiple subpanels, FiOS prewiring, Cat5/Cat6 networking, and a conditioned attic with future-ready electrical circuits. The fully finished basement adds tremendous additional living and entertaining space. Step outside to your beautifully manicured private backyard oasis featuring a large patio, propane fire pit, underground-powered landscape lighting, and an in-ground sprinkler system. The home is also equipped with soffit and peak outlets specifically designed for seamless holiday lighting displays, allowing for clean, extension-cord-free decorating with dedicated switch controls throughout the exterior. A rare feature for the area, the property offers two separate driveways along with a detached 2-car garage featuring 14-foot ceilings, tiled floors, drywall finish, mini-split heating and cooling, 240-amp service, and built-in compressed air lines - ideal for car enthusiasts, hobbyists, or workshop use. Major improvements include a dormer and roof completed in 2019, adding both style and long-term value to the home. Conveniently located close to shopping, restaurants, local preserves, parks, and the LIRR, this one-of-a-kind property offers a rare combination of luxury, craftsmanship, smart technology, and everyday convenience.