Kitchen cabinets typically fasten to wall studs; islands attach to the floor with cleats or brackets anchored into wood or concrete.
New cabinets don’t just sit in place—installers lock them to solid structure so doors line up, drawers glide, and countertops stay crack-free. Wall runs are fixed to studs. Base sections are leveled with shims, screwed to each other, and set tight to the wall. Islands and peninsulas gain floor anchors. The best method depends on layout, subfloor, and the cabinet box style.
Attaching Base Units To Floors And Walls — What Pros Do
Most base boxes along a wall take their strength from the wall, not the floor. Installers find the floor’s high spot, strike level lines, and bring every box up to those lines with plastic or wood shims. Then they drive screws through the cabinet’s back rail into studs. Neighboring units are clamped and screwed through face frames or side panels so the run acts like one piece. The toe-kick meets the floor, yet the fasteners land in framing, not into the finish flooring.
Freestanding sections—an island or a snack bar—need their own anchor. The common approach is a pair of 2×4 cleats screwed to the subfloor inside the island footprint. The cabinet slides over the cleats and locks in with screws. On concrete, installers switch to concrete screws or wedge anchors. With tile or stone on top, a pilot hole and a masonry bit prevent cracks. Metal brackets work too, especially with flat-pack lines that ship matching hardware.
| Situation | Primary Attachment | Typical Fasteners/Anchors |
|---|---|---|
| Base run along a wall | Into wall studs through back rail; boxes joined side-to-side | 2½ in. cabinet screws through shims; #8 or #10 truss-head |
| Island on wood subfloor | Cleats inside footprint | 3 in. wood screws or lag screws into subfloor/joists |
| Island on concrete slab | Cleats or brackets | Concrete screws (e.g., Tapcon) or wedge anchors |
| Peninsula off a wall | Wall studs plus floor cleat near free end | Stud screws; floor cleat screws or brackets |
| Toe-kick base with leveling legs | Legs adjusted to level; wall fasteners carry the load | Leg locks; screws into studs |
| Over finished floating flooring | Anchors bypass floating layer | Through-holes to subfloor; never trap the floating planks |
Why Wall Runs Rarely Screw Into The Floor
Cabinet boxes prefer a stable, plumb reference. Walls and studs give that reference. Floors can dip or crown across the room. If you shoot fasteners down through a base, the box twists to match the floor. Doors rub, reveals go uneven, and stone counters can crack under point loads. Fastening into studs keeps the run straight while shims take up the floor’s waves.
Leveling And Scribing In Plain Steps
- Map studs, plumbing, and outlets. Mark stud centers across the layout.
- Find the floor’s high spot with a level or laser. Strike a level line that represents the finished counter height minus cabinet and top thickness.
- Set the first base at the high spot. Shim under side panels until the box reads level left-to-right and front-to-back.
- Tack the box to the wall. Drive screws through the back rail into studs, through shims so the box stays square.
- Set the next box, clamp faces flush, and screw the frames or case sides together before tying it to studs.
- Scribe the end panel or filler where a wall bows. Plane or trim for a tight, clean fit.
Anchoring An Island To The Floor
An island can’t count on a wall, so installers give it a base that can’t budge. Cleats and brackets are the go-to choices. A pair of 2×4 runners, inset from the layout by about half an inch, get screwed to the subfloor. The cabinet slips over those runners. Screws through the toe-kick or base rail pull the box tight to the cleats. With brackets, angle plates tie the box to the floor from the inside.
Wood Subfloor: Cleats And Lags
On plywood or plank subfloors, wood screws or lags offer strong bite. Many installers aim for joists when they can. If the layout misses joists, longer screws into thick subfloor still work, as the island’s weight and the wide cleat spread resist racking.
Concrete Slab: Concrete Screws Or Wedge Anchors
On slabs, drill a pilot hole with a hammer drill, blow out dust, and drive purpose-made concrete screws. Where loads run higher—thick stone tops or seating overhangs—wedge anchors deliver extra pull-out strength. A bead of construction adhesive under the cleat cuts squeaks and adds grip, but fasteners carry the load.
Tile Over Wood Or Slab
Tile needs careful drilling. A masonry bit with tape as a depth stop keeps the hole clean. The anchor must reach the subfloor or slab below. Don’t sink fasteners into the tile only. When layout allows, set cleats before tile goes down, then cut tile to the toe-kick for a clean seam.
Pro-Level Fasteners, Spacing, And Torque
Cabinet screws have large, flat heads that pull cases tight without chewing through thin back rails. Length typically runs 2½ inches into studs for wall runs. For islands, 3-inch wood screws or ¼-inch lags are common in wood, while 3/16-inch or ¼-inch concrete screws handle slabs. Space fasteners about every 16 inches along rails and cleats. Pre-drill near panel edges to avoid splits. Drive snug, not stripped.
When Brackets Beat Cleats
Brackets shine with narrow bases or when you need access under the cabinet. Flat-pack systems often ship steel plates designed for that line. Some brackets anchor to the slab and the cabinet side, keeping the toe area open for vents or lighting drivers.
Flooring Sequence And Movement
Floating planks expand and contract. Trapping those planks under heavy boxes can cause buckles or gaps. Installers set cabinets first, then run floating flooring up to the base with a small gap hidden by shoe molding. Nail the trim to the cabinet, not the flooring, so the planks can slide. Glue-down or nail-down floors act differently; many crews still prefer cabinets first to save material and avoid damage, with finish height handled by underlayment or toe adjustments.
Code, Standards, And Trusted How-Tos
Good practice lines up with respected trade sources. A clear walk-through on leveling, shimming, and fastening wall runs appears in This Old House’s cabinet install guide, which shows screws driven through shims into studs and faces clamped flush. For slab anchors, the Tapcon concrete screw guide explains pilot sizing and dust removal that keeps anchors biting hard. Links sit below for easy reference.
See the This Old House cabinet install steps and the Tapcon concrete screw guide for details that match the methods described here.
Box Construction And Where Screws Should Land
Face-Frame Lines
Many North American lines use face frames. When two bases meet, clamps pull the frames flush. A pair of trim-head screws through the frames locks the seam. Stud screws pass through the back rail near the frame so the force carries into the thickest part of the box. Where a sink base lacks a full back, add a ledger or blocking on the wall to catch fasteners at the right height.
Frameless Lines
European-style boxes depend on dense side panels. Use wide-headed cabinet screws in the back rail or metal hanging strip, and join cases with confirmat screws or through-bolts placed near the front and back. Pre-drill accurately so the laminate skin stays clean and the core holds tight. Because the sides do the work, even spacing of fasteners matters.
Toe-Kicks, Legs, And Bases
Some systems ride on adjustable legs with clip-on toe-kicks. Others sit on integrated bases. Either way, the goal is a level platform. Legs make quick work of uneven floors and help with water protection during a small leak. Integrated bases give a solid feel and more bearing surface for shims. In both cases, the wall fasteners keep the run locked while the toe hides gaps at the floor.
Planning Tips That Prevent Callbacks
Lay Out Level Lines Before A Single Box Goes In
Laser or long level, your choice. Once that line is on the wall, every shim and screw aims at that datum. Countertops rest flatter, and appliance gaps line up.
Join Boxes Before You Lock To Structure
Clamping faces first gives a flush seam. Pilot holes through face frames keep splits away. Then sink stud screws. That sequence produces a straight, tight run.
Add Blocking Where Studs Miss The Rails
Open walls give a chance to add 2× lumber where backs will land. Blocking behind drywall means your screws always hit meat, even where studs are off layout.
Protect Plumbing, Wires, And Appliances
Pilot holes and short screws near services save headaches. Set dishwashers and ranges after the boxes are anchored so clearances stay true.
Second Reference Table: Floor Types And Anchor Choices
| Floor/Subfloor | Common Anchors | Notes |
|---|---|---|
| Plywood or plank | 3 in. wood screws; ¼ in. lag screws | Aim for joists when layout allows |
| OSB | Coarse-thread wood screws; lags into joists | Use longer screws for solid bite |
| Concrete slab | 3/16–¼ in. concrete screws; wedge anchors | Hammer drill; clear dust; set to depth |
| Tile over wood | Through-holes to subfloor; wood screws | Drill tile cleanly; avoid cracking |
| Tile over slab | Concrete screws or anchors | Use masonry bit; avoid tile-only grip |
| Floating laminate/LVP | Do not pin with fasteners | Run planks to toe; leave expansion gap |
Troubleshooting Common Problems
Island Wiggles Or Creaks
Check cleat contact. If the base sits proud, add shims between cleat and box and snug the screws. On wood, add a second cleat run across the short direction. On slab, confirm hole depth and anchor size. A thin coat of adhesive under cleats can silence minor squeaks.
Gaps At The Wall
Walls rarely run straight. Scribe and plane end panels or use fillers to close daylight. Add a strip of blocking behind drywall where the rail needs a bite but a stud misses the mark.
Doors Out Of Plane
First, check level across the run. Shim low spots under side panels. Then check the wall fasteners—loosen, tweak shims, and re-tighten. Use hinge adjustments last, after the boxes sit dead level.
Floor Heaves Against A Base
Floating planks swell. If trim nails pin the floor to the toe, pull the nails and re-attach the shoe to the cabinet only. Leave the expansion gap clear.
Materials And Tools Checklist
Have the kit on hand so the process moves fast and clean:
- 2×4 cleats or steel brackets for islands
- Cabinet screws, 2½ in. for studs
- Wood screws or lags, 3 in. for wood subfloors
- Concrete screws or wedge anchors for slabs
- Shims, plastic or wood
- Level or laser; stud finder
- Clamps, drill/driver, countersink bit
- Hammer drill and masonry bits for tile or slab
- Construction adhesive and painter’s tape
Small Details That Make A Big Difference
Run a strip of tape on tile where you plan to drill; it reduces bit wander. Pre-finish toe-kicks and removable panels so touch-ups stay minimal. Label every screw location through the back rail while the boxes are empty; later access gets tricky under sinks and corners. Where an island hosts seating, upgrade to wider cleats or more anchors along the overhang side for better racking resistance.
Recap: Where The Load Actually Goes
Perimeter bases lean on stud screws and shims for level. The toe meets the floor, yet fasteners live in studs. Islands and peninsulas tie down with cleats or brackets set to the subfloor or slab. Pick anchors that match the substrate, keep fastener spacing steady, and mind movement gaps where floating planks run. Follow those rules and the boxes stay put, the stone stays calm, and doors swing true.