Knock-down frames can reduce the shipping volume for each opening by more than half compared with pre-hung units, especially on multi-door packages, which often translates into double-digit freight savings without compromising a clean, modern look.
Pre-Hung vs. Knock-Down: What’s Riding on the Truck
Pre-hung doors ship as complete, factory-aligned door-and-frame units, so your crew drops the whole assembly into the rough opening instead of building a frame around a slab on site. That factory prep is why pre-hung doors are popular for fast, repeatable installations in both renovations and new builds.
Knock-down (KD) frames ship as three pieces—hinge jamb, strike jamb, and head—that lock together in the opening with clips or screws; you then hang a separate slab. Because those components are flat-packed, they are lighter, slimmer, and far easier to stack on a pallet or tuck into remaining truck space.
Commercial hollow-metal suppliers routinely describe KD frames as the cost-effective, logistics-friendly option, while welded or fully pre-hung frames are the go-to when you prioritize strength and seamless corners over shipping efficiency.
Why Carriers Charge More for Pre-Hung Units
Freight carriers do not just charge by how heavy your shipment is; they use dimensional weight pricing, which treats a bulky but light package as if it weighs more because it eats up space in the truck. Doors fall squarely into that category, which is why the way you package each opening matters as much as the pounds on the scale.
A single 3'-0" x 6'-8" pre-hung interior door with protective packaging can take up around 8–9 cubic feet as a rigid rectangle. The same opening with a KD frame lets you stack the jambs into a tight bundle, often cutting frame-related volume by well over half before you even count the slab.
With pre-hung units, you also pay for more awkward handling, often requiring two people or a material lift for each unit. You face a higher risk of frame twist or corner damage if a pallet tips or a strap loosens. You also have fewer loading options on small trucks and elevators, which limits how many openings you can move per run.
Quick Math: A 20-Door Interior Package
On a 20-door interior package for a boutique apartment building, assume each pre-hung unit consumes about 8.5 cubic feet once wrapped and palletized. That is roughly 170 cubic feet dedicated just to doors, which can easily dominate a small less-than-truckload shipment.
Switch those frames to KD and ship slabs and frames separately, and the frame bundles might drop to around 2 cubic feet of space per opening. Now the frame portion of that shipment is closer to 40 cubic feet—about 75% less volume for the most awkward part of the load.
Because many freight quotes scale with volume and handling complexity, that kind of reduction commonly yields freight savings in the 20–40% range for the door package once you cross 10–15 openings. On multi-floor projects where you are staging in waves, the smaller, lighter bundles also cut time spent jockeying material through corridors and up elevators.
Freight rates are highly regional and contract-based, so treat these percentages as directional benchmarks and verify them with your carrier before you lock in a frame strategy.
When Shipping Savings Justify Knock-Down Frames
Shipping is only one line item, so the smart move is to weigh it against labor and finish expectations, not chase savings in a vacuum. Installing a new interior door typically runs a few hundred dollars per opening, and pre-hung doors often cost 200 more than slabs but buy back labor by reducing on-site fitting and alignment work.
In practice, KD frames tend to win on shipping and overall cost when you are ordering 10 or more openings and shipping them any real distance. They are especially helpful when access is tight—think urban infill, basement studios, or remodels up narrow stairs—and when you want the flexibility to fine-tune reveals or wall finishes on site rather than committing to factory-set casing.
Pre-hung or welded frames still earn their keep where a zero-joint look, fire or security ratings, or aggressive schedules matter more than freight, especially on high-traffic entries and feature doors. For the rest of your interior openings—the bedrooms, studies, and back-of-house doors—stepping down to knock-down frames is one of the cleanest ways to control shipping costs while still delivering a crisp, modern frame line your clients will notice every day.
