Most gates get replaced for one of three reasons: the old one sags until it drags on the concrete, the posts have rusted out at ground level, or the opening was never a standard size in the first place. Custom metal gate fabrication exists for that third problem and solves the other two along the way — the gate is built to the opening you actually have, not trimmed down from something that came off a pallet. In older neighbourhoods around Vernon, Boyle Heights and Maywood, almost nothing is square. Driveways slope toward the street for drainage, property walls were poured at different times, and a driveway opening often measures an inch or two wider at the top than at the bottom. A stock gate hung in that opening either scrapes or leaves a gap a dog can get through.
Custom gate fabrication starts with someone standing in the opening with a level, a tape and a string line, and the measurements taken that day dictate everything that follows. The clear opening gets measured at the top, the middle and the ground. The slope across the opening and the slope front-to-back both get recorded, because a swing gate on a driveway that falls toward the street will bind on its own arc unless the bottom rail is cut to rake, or the hinges are set to allow lift as the gate opens. The condition of the posts or the wall matters as much as the numbers. A gate is only as good as what it hangs from, and a hinge post set in a shallow footing will lean within a year under the weight of a steel driveway gate. If the existing posts are sound, they can often be reused; if they're rusted thin at the base where water has sat, new posts and new footings are part of the job and you should expect them to be priced in rather than discovered later.
This is also when the design gets pinned down. Pickets spaced close enough to stop a small dog, infill panels or perforated sheet for privacy, a solid kick plate along the bottom, an arched or straight top, scrollwork, mail slot, pedestrian gate matched to the driveway gate so the frontage reads as one piece. Each of those changes the fabrication hours more than it changes the material cost. A plain picket gate is a frame, a few rails and repetitive welds. The same gate with ornamental work, a curved top rail and matched panels on a separate walk gate is several times the shop time.
Most driveway and yard gates here are built from mild steel tube and square bar, which is strong, easy to weld and repairs cleanly years later. Wrought iron styling is usually mild steel worked to look the part. Aluminium is worth asking about where weight matters — a long cantilever slide gate, or a swing leaf hung on an old masonry pillar you'd rather not load up — and it won't rust, though it costs more and dents easier. Stainless and heavier structural steel show up on commercial and industrial frontages, where the gate has to take a knock from a forklift or a delivery truck.
Whatever the metal, the finish is what decides how it looks in five years. Rust in this part of Los Angeles starts where water sits and where the coating got thin: the bottom rail, the inside of hollow posts, and every weld that was painted over without being ground and primed. Galvanizing before coating is the most durable route. Powder coat is tougher than brush-applied enamel and holds colour better, but it has to be done before hardware goes on, and touching it up after a repair never matches perfectly. Ask what happens to the cut ends and the inside of the tube, because that's where a cheap job rots from.
Decide early whether the gate swings or slides, because the fabrication differs from the frame out. Swing gates need clear arc inside the property and level enough ground that the leaf doesn't catch — single leaf for narrow openings, double for wide ones to keep each leaf light. Slide gates suit short driveways and tight street parking in Bell and Huntington Park, but need run-back room alongside the opening, either on a bottom track or built as a cantilever with a counterbalance tail.
If an opener is going in now or later, say so before anything is cut. Automated gates need hinges rated for the load, a straighter and stiffer frame than a hand-operated gate, mounting points welded in for the arm or the rack, and a conduit path for power and safety sensors. Retrofitting all of that to a gate built for hand use is slower and uglier than building it in. Before booking, ask who sets the posts, how the welds are prepared and coated, whether the gate is assembled and checked in the shop before it arrives, and who comes back to adjust the hinges after the first few weeks of use — a heavy gate always settles a little.