Undermount vs Side-Mount Drawer Slides?
By The DIYPicks Team · Updated July 2026
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Blum TANDEM plus BLUMOTION 563H Undermount Drawer Slide (21 in)
The gold standard for a kitchen renovation where drawers carry real weight and you want them invisible. Unforgiving of sloppy drawer boxes, but nothing else glides or closes this well.
| Type | Undermount, concealed, full extension |
|---|---|
| Length | 21 in (9–21 in available) |
| Load rating | 100 lb |
| Soft-close | Yes (integrated BLUMOTION) |
| Extension | Full extension |
| Drawer material | 1/2 in–5/8 in sides |
| Adjustment | 4-dimensional (height, tilt, side, depth) |
Liberty D80622C 22 in Side-Mount Ball-Bearing Full-Extension Slide
The workhorse side-mount for shops, closets, and budget kitchens. You trade the hidden look and soft-close for a slide that's cheap, tough, and nearly foolproof to hang.
| Type | Side-mount, ball-bearing, full extension |
|---|---|
| Length | 22 in (16–24 in available) |
| Load rating | 100 lb |
| Soft-close | No (soft-close model 942205 available separately) |
| Extension | Full extension |
| Clearance | 1/2 in per side required |
| Finish | Zinc plated steel |
Our verdict
Undermount slides (Blum Tandem) hide completely under the drawer, add integrated soft-close, and give a premium look — but they cost more, need locking devices, and demand a precisely built drawer box. Side-mount ball-bearing slides (Liberty) are cheaper, stocked everywhere, and far more forgiving to install, at the cost of a visible slide on each side and no soft-close on the base model. For a kitchen reno where drawers carry weight and you want them invisible, choose undermount. For a workshop, closet, garage, or budget build — or any drawer box that isn't perfectly square — side-mount is the smarter, easier pick.