Kitchen Cabinet Construction Guide

What Is MDF?

MDF is an engineered wood product — it contains no solid timber. The fine fibres give it a smooth, consistent surface free of knots, voids or grain variation. It is heavier than chipboard of equivalent thickness and machines cleanly, making it easy to route and profile.

• Density: ~700–800 kg/m³ (heavier than chipboard)
• Smooth surface: takes paint and primer exceptionally well
• No grain direction: equal strength in all directions
• Typical thickness for carcasses: 18mm
• Available in moisture-resistant (MR) grade for kitchen use

Pros & Cons

Moisture-Resistant MDF

For kitchen use, always specify moisture-resistant (MR) MDF, identifiable by its green core colour. Standard MDF will swell and delaminate rapidly if exposed to steam, condensation or a minor water leak.

• MR MDF has modified resin that resists moisture absorption
• Identified by green-tinted cross-section
• Still not waterproof — prolonged saturation will cause damage
• Ask your kitchen supplier explicitly: “Is this moisture-resistant MDF?”
• All quality kitchen carcasses should use MR grade as standard

What Is Chipboard / MFC?

Raw chipboard is a compressed board of wood chips. In kitchens, it is almost always supplied as Melamine-Faced Chipboard (MFC) — a thin melamine resin surface bonded to both faces of the chipboard during manufacture. This gives a smooth, hardwearing, easy-clean surface in white, grey or woodgrain effects.

• Density: ~600–680 kg/m³ (lighter than MDF)
• MFC face: smooth, hard, easy-wipe surface
• Standard thickness: 16mm or 18mm
• The workhorse of the flat-pack and trade kitchen industry
• Available in moisture-resistant (P5 / E1) grades

Pros & Cons

The Edge Banding Issue

Raw chipboard edges are the Achilles heel of MFC carcasses. Where cuts are made (for hob cutouts, pipe access holes, shelf pin holes), the chipboard core is exposed. If moisture reaches these raw edges, swelling begins immediately. Quality of edge banding is critical:

• Budget: 0.4mm PVC edge tape — peels, chips, poor moisture seal
• Mid: 1mm ABS edge banding — durable, good seal
• Premium: 2mm ABS edge banding — radius-profiled, excellent seal
• Laser-edge banding (melted-on, no visible glue line) is the premium standard
• Always check edge banding quality at the back of drawers and inside cabinets

Why Plywood Is Superior

The cross-laminated construction of plywood gives it properties that chipboard and MDF cannot match:

• Screw holding: Screws grip into alternating grain layers — far stronger than chipboard
• Moisture resistance: Marine and WBP (Weather & Boil Proof) plywood resists prolonged moisture without swelling
• Strength-to-weight: Lighter than MDF at equivalent structural strength
• No sag: Plywood shelves span further without deflection
• Impact resistance: The layered construction absorbs knocks without chipping or crumbling
• Repairability: Damaged areas can often be filled, sanded and refinished

Pros & Cons

Plywood Grades for Kitchens

• Birch Ply (BB/BB grade): The most common for kitchen carcasses. Smooth, consistent, pale birch veneer. Takes paint and lacquer well.
• Hardwood Ply: Slightly stronger than birch. Used in bespoke joinery and high-end kitchen manufacture.
• WBP (Weather & Boil Proof): Exterior-grade adhesive bond. The correct grade for all kitchen applications.
• Marine Ply: Highest quality, void-free core. Used in boat-building — overkill for most kitchens but technically the best.
• Always specify: WBP bonded, birch ply, minimum 18mm for carcass panels

Exposed Plywood as a Design Feature

In contemporary and industrial kitchen design, the visible edge layers of birch plywood have become a sought-after aesthetic in their own right. Bespoke joiners and high-end kitchen manufacturers increasingly leave plywood edges exposed — sealed with clear lacquer — as an honest, tactile design statement.

• Popular in Scandi, industrial and architect-designed kitchens
• Seal edges with clear matt lacquer or hardwax oil
• The layered edge is a mark of quality — not something to hide
• Combine with handleless doors and minimal hardware for maximum impact

When Solid Wood Is Used

Full solid timber carcasses are almost exclusively found in bespoke, hand-built cabinetry. More commonly, solid wood appears as:

• Dovetail drawer boxes: Solid oak or beech drawers with visible hand-cut or machine-cut dovetail joints — a hallmark of premium kitchen quality
• Shelf edging: Solid wood lipping on plywood or MDF shelves to prevent chipping and add a premium feel
• Internal framing: Solid timber corner posts and rails in traditionally-built face-frame cabinetry
• Furniture-grade interiors: Some premium manufacturers use solid oak or walnut for visible interior surfaces of larder units

Pros & Cons

Solid Wood Dovetail Drawers

The dovetail joint is one of woodworking’s strongest connections — the interlocking tapered tails resist pulling apart under load. Solid dovetail drawer boxes are a reliable indicator of a premium quality kitchen because they require skill and material investment that budget manufacturers avoid.

• Traditional hand-cut dovetails: highest end, bespoke only
• Machine-cut dovetails: common in premium fitted kitchens (Howdens Clerkenwell, Wren Premier etc.)
• Look for: solid oak or beech sides, dovetail front & back joints
• Base: solid ply or MDF panel in groove (not stapled thin sheet)
• A dovetail drawer box will outlast the kitchen itself if treated well

How Aluminium Systems Work

Extruded aluminium profiles form the top, bottom and vertical members of the cabinet frame. Infill panels slot or clip into the frame. The frame itself never swells, rots or corrodes — giving a theoretical lifetime that far exceeds any wood-based panel system.

• Frame: powder-coated aluminium extrusion
• Infill options: glass, acrylic, aluminium sheet, melamine board
• Fully modular — individual sections replaceable
• Very lightweight vs panel construction
• Particularly popular in contemporary handleless kitchens

Pros & Cons

Key Aluminium System Brands

• Leicht: German premium manufacturer. Uses aluminium framing in their contemporary ranges. Available through UK showrooms.
• Bulthaup: The benchmark of aluminium kitchen systems. b3 system uses a full aluminium workshop concept. Extremely premium.
• SieMatic: German brand, offers aluminium-framed Pure range. Used in architect-designed kitchens worldwide.
• Arclinea: Italian contemporary kitchen with aluminium frame options.
• Note: most UK high-street kitchen brands do not offer aluminium frame systems — these are typically found through specialist kitchen designers.

Frameless (European / Box) Construction

The dominant system in UK kitchens today. The carcass is a simple box with no front frame — the door or drawer front is hung directly from the side panels using concealed hinges. The door fully covers the front of the carcass.

• Maximum interior space — no frame eating into the opening
• Clean, minimal appearance — works with all door styles
• Doors hung on 35mm cup hinges (Blum, Grass, Hettich)
• Full-overlay or inset door options available
• Standard in virtually all UK kitchen retailers and manufacturers
• Easier to install and adjust than face-frame

Face-Frame Construction

A solid timber frame is applied to the front of the carcass box before doors and drawers are fitted. Traditional American and country British cabinetry style. The visible frame becomes a design feature and adds significant rigidity to the carcass.

• Solid timber frame (typically 38–50mm wide)
• Adds rigidity — very sturdy feel
• Slightly reduced interior opening (frame intrudes)
• Works best with inset or partial-overlay doors
• Traditional, furniture-like appearance
• Common in bespoke and American-style kitchens
• More complex to install than frameless

Inset vs Overlay Doors

Regardless of whether the carcass is frameless or face-frame, door fitting style is a separate decision:

• Full overlay: Door completely covers the carcass front. Minimal gap between doors. Most common in modern UK kitchens.
• Half overlay: Used where two doors share a divider panel — each covers half the panel.
• Inset: Door sits flush inside the cabinet opening. The most exacting and expensive fitting. Requires precise manufacturing tolerances. The mark of a truly bespoke kitchen.
• Inset doors require more skill, larger reveals and higher quality hardware to allow for wood movement.

Back Panels

The back panel is critical for the structural integrity of the carcass — it prevents the box from parallelogramming (racking) under load. It also keeps out dust, pests and moisture from the wall.

• Budget: 3mm hardboard — very thin, minimal racking resistance, punctures easily
• Standard: 6mm MDF or chipboard — adequate for most wall units
• Quality: 8mm MDF, chipboard or plywood — noticeably stiffer
• Premium: 12mm plywood or MDF — fully rigid, excellent structural contribution
• Back panels should be dadoed in (slotted into a routed groove in the side panels) not just stapled on — a dadoed back adds massive rigidity vs a stapled-on back

Bottom Panels (Base Units)

The bottom of a base unit carries the worktop and all the weight of contents. This panel takes more load than any other in the carcass and should be the thickest and most moisture-resistant in the whole unit.

• Minimum acceptable: 16mm P5 chipboard
• Better: 18mm P5 chipboard or MR MDF
• Best: 18mm WBP plywood
• Check if the bottom panel is edged — an exposed chipboard bottom inside a sink unit will swell from drips and condensation
• Sink base units: should have a fully sealed bottom — ideally plywood

Shelf Thickness & Sagging

Interior shelves sag under the weight of heavy crockery, appliances and tins. The risk of sagging increases with span width and reduces with thickness.

• 600mm span, 16mm chipboard: will sag noticeably under heavy load
• 600mm span, 18mm chipboard: acceptable for most use
• 600mm span, 18mm plywood: excellent — no sagging
• 900mm+ spans: use 22mm board minimum or add a central support
• Anti-sag bars (metal rods under the shelf): an affordable fix but a sign of thin shelving
• Fixed shelves add significantly more rigidity than adjustable — consider fixing the central shelf in tall units

The 35mm Cup Hinge

The standard concealed hinge used in virtually all frameless kitchen cabinets. A 35mm diameter cup is routed into the back of the door, and the hinge arm clips or screws to the cabinet side panel. Fully adjustable in three directions (in/out, left/right, up/down) after installation.

• 3D adjustment: essential for getting doors perfectly aligned
• Soft-close: built-in damper slows the door in the last 15° of travel. Non-negotiable for quality kitchens.
• Push-to-open: no handle needed — press the door to open. Used in handleless kitchens.
• Standard opening angle: 110° (standard), 165° (wide-angle for corner units)
• Load rating: typically 20–40kg per hinge pair

Hinge Brands: Why It Matters

The difference between a premium hinge brand and a budget hinge is felt every single time you open a door. Premium hinges have tighter tolerances, more consistent soft-close damping and vastly longer cycle-rated lifespans.

• Blum (Austria): The global benchmark. CLIP top BLUMOTION hinges rated to 200,000 cycles. Used in virtually all premium UK kitchen brands.
• Hettich (Germany): Premium quality, close competitor to Blum. Sensys hinge range excellent.
• Grass (Austria): Premium brand, used in German kitchen manufacture.
• Salice (Italy): High quality, popular in Italian-manufactured kitchens.
• Generic Asian hinges: Budget kitchens. Often rated to 30,000–50,000 cycles. Soft-close damping inconsistent. Avoid.

Lift-Up & Folding Door Hardware

For wall units with upward-opening doors (bi-fold or lift-up), specialist hardware replaces the cup hinge:

• Blum AVENTOS: The industry standard lift-up system. HF (bi-fold), HL (single flap), HS (parallel lift). Fully soft-close. Comes in various force settings for different door weights.
• Hettich AvanTech: Premium alternative lift-up system.
• Force setting must match door weight — always declare door material and dimensions to your kitchen supplier
• Lift-up doors dramatically improve accessibility vs traditional hinged doors

Drawer Box Materials

• Budget chipboard box: MFC-faced chipboard sides and front. Stapled or dowelled. Base often thin hardboard. Heavy, prone to sag, feels cheap. Found in entry-level flat-pack.
• MDF drawer box: Smoother than chipboard. Better base. Mid-range standard.
• Metal drawer system (Blum Legrabox / Hettich InnoTech): Thin steel side walls, integrated rear bracket. Very strong, very light, clean appearance inside the drawer. Premium standard.
• Solid wood dovetail: Solid oak or beech sides with dovetail jointed corners. Premium to bespoke. The finest drawer box construction available.

Drawer Runner Systems

The runner determines how the drawer slides. This is the most important component for long-term feel and reliability:

• Budget bottom-mount runners: Two plastic slides under the drawer base. Noticeably wobbly side-to-side. Not soft-close. Found in budget kitchens.
• Side-mount runners: Metal runners on each side of the drawer. Smoother but not as refined as undermount.
• Undermount runners (Blum TANDEM / Hettich Quadro): Hidden under the drawer base. Completely invisible. Soft-close, full extension, 3D adjustment. The gold standard for kitchen drawers. Load-rated to 30–70kg.

Blum LEGRABOX vs TANDEM

Blum’s two premium drawer systems and when to use each:

• TANDEM (with BLUMOTION): Undermount runner only. Drawer box is separate (any material). More affordable, widely used in mid-premium kitchens. Available in standard and full extension.
• LEGRABOX: Integrated metal drawer side walls with undermount runner combined. Thinner walls = more interior space. Higher load rating (up to 70kg). Very contemporary appearance. Used in top-end kitchen brands.
• Both are soft-close as standard. Both have 3D adjustment. Both carry a 10-year warranty from Blum.

Flat-Pack Carcasses

Panels are cut, edged and drilled in the factory, then boxed flat for delivery. Assembly happens on site using cam locks, dowels or screws.

Pre-Assembled / Rigid Carcasses

The carcass is fully assembled in the factory — glued, stapled and often nailed. Delivered as a complete box. The rigid construction is stronger than flat-pack assembly and eliminates on-site assembly error.

Which to Choose?

• For most fitted kitchens installed by a professional: pre-assembled is better — stronger, faster, no risk of poor assembly
• For difficult access (steep staircase, narrow hallway, loft conversion): flat-pack is necessary — you simply cannot get a pre-assembled 600mm base unit up a tight staircase
• For DIY installation: flat-pack is fine if assembly instructions are followed carefully and cam locks are fully tightened
• Trade tip: always glue dowel joints in flat-pack carcasses during assembly — PVA adhesive dramatically increases rigidity over cam locks alone

Carcass Checks

• ✓ Ask: “Is this P5 chipboard / MR MDF / WBP plywood?” Get a written answer.
• ✓ Check the carcass thickness — tap the side panel. Solid thud = 18mm+. Hollow tap = 16mm or thinner.
• ✓ Look inside a base unit — is the bottom panel edged? An exposed chipboard bottom near the sink is a red flag.
• ✓ Check the back panel — is it dadoed in (slotted into a groove) or just stapled on? Dadoed = quality.
• ✓ Look at the back panel thickness — poke it. 3mm hardboard flexes. 8mm+ is rigid.
• ✓ Check shelf thickness — push down in the centre of a laden shelf. Quality shelves don’t flex.

Hardware Checks

• ✓ Open and close every door. Does it self-close smoothly and silently? Blum/Hettich soft-close is consistent and quiet.
• ✓ Push a door slightly off-centre and release — does it self-correct and close straight? Premium hinges do.
• ✓ Open every drawer. Pull it side-to-side slightly while open — premium undermount runners have zero side-play.
• ✓ Look at the inside of the drawer box — is it MFC, solid wood or metal? Stapled thin hardboard base = budget.
• ✓ Ask: “What brand of hinges and drawer runners?” Blum, Hettich or Grass = quality. No-brand = flag.
• ✓ Check that all hinges have 3D adjustment screws — budget hinges often have only 1D or 2D.

Edge Banding & Finish Checks

• ✓ Run your finger along the edge of a door or carcass panel. Premium ABS or laser-edged banding is smooth with no perceptible join. Budget tape has a visible glue line.
• ✓ Look at the inside rear corner of a drawer — is the edge banded? Budget drawers leave raw chipboard inside.
• ✓ Check the finish inside the cabinet at the back — quality cabinets are fully finished inside. Budget ones use thin melamine that peels at the corners.
• ✓ Inspect the hinge drilling — clean, sharp holes indicate CNC precision. Ragged or off-centre holes indicate poor manufacture.
• ✓ Check that all cam lock holes are clean and correctly positioned — misaligned holes cause weak joints.