The short answer
For new construction, order prehung. The door arrives already hung in its jamb with hinges set, so carpenters only plumb, shim and fasten it. Slabs are the cheaper part, but they need a frame on site plus hinge and lock prep. They suit renovations where good frames are already in place.
What you get
| Prehung | Slab | |
|---|---|---|
| Door | Yes | Yes |
| Jamb (frame) | Yes, sized to the wall | No |
| Hinges | Mounted | No |
| Lock and strike prep | Bored and prepped | Usually bored for the knob |
| Work on site | Set, shim, fasten, case | Build or reuse a frame, mortise hinges, hang, case |
| Price per unit | Higher | Lower |
| Best for | New openings and new construction | Renovations with sound existing frames |
Why prehung wins on new multi-unit work
- Less carpentry per opening. Hinge mortises, jamb assembly and door fitting are done at the factory, so the crew isn’t repeating that work hundreds of times.
- Consistent reveals. Every door sits the same way in its frame, which shows in finished hallways.
- Fewer callbacks. Factory-hung doors are less likely to bind or rub once the building settles.
What prehung needs from you
- Handing. Every prehung door is left-hand or right-hand. Send counts, or mark the swing on the plans.
- Jamb width. The jamb has to match the finished wall thickness. A 2×4 wall with ½″ drywall both sides takes a 4-9/16″ jamb. See door jamb width explained.
- Storage space. Prehung units are bulkier than slabs, so plan where pallets will sit on site.
When slabs make sense
Slabs are the right call when the frames are already in good shape: a renovation, a like-for-like swap, or a phase where frames were built on site. They also work for barn doors, which hang on a track instead of a jamb.
We supply both. Our prehung doors come in 4-9/16″ finger-jointed pine jambs as standard, with other jamb widths made to order.
Sources
Code requirements change and local rules vary. Confirm sizes and clearances with your designer and building department before ordering. We supply doors and trim; we’re not a code consultant.
