Description
Traditional multi-coat internal wet plaster needs a corner bead that survives the drying phase, not just the working day. The Wet Plaster Corner Aluminium 3 m is an extruded aluminium angle profile sized for browning-and-set, bonding-and-skim, and sand-and-cement build-ups at 12–19 mm total finished depth, supplied in a full storey-height 3,000 mm length and stocked as part of the render and plaster corner beads range. It is specified to eliminate the rust-bleed failure mode that affects galvanised steel beads in kitchens, bathrooms, and other persistently damp internal rooms.
What the Wet Plaster Aluminium Corner Bead Does in an Internal Plaster System
The Wet Plaster Corner Aluminium 3 m is an extruded aluminium angle bead, 3,000 mm long, dimensioned for internal multi-coat wet plaster build-ups at 12–19 mm total depth and classified A1 for reaction to fire — subject to the wider wall assembly's fire strategy. Metal wet plaster beads sit inside the plaster coats rather than on the surface: the perforated wings key mechanically into the undercoat, and the nose sets the finished plaster depth at the corner while the skim is ruled off to it.
At a full 3 m length, the profile covers a UK storey-height corner in a single piece, removing the horizontal joint that is the most awkward detail to keep invisible under a raked light source after decoration. The wider wing geometry typical of wet plaster beads gives a generous keying surface for thick undercoat materials and resists the shrinkage movement of heavy multi-coat plaster as it dries — so the arris line stays where it was set on the day of fixing.
What Makes the Wet Plaster Aluminium Bead Worth Specifying
- Aluminium construction for damp internal rooms: resists alkaline attack from freshly mixed wet plaster during the drying phase, eliminating the rust-bleed at the arris that affects galvanised steel beads in kitchens, bathrooms, and basements.
- Full storey-height 3,000 mm length: removes the horizontal joint from a typical UK internal corner run, producing one continuous arris line from floor to ceiling.
- Sized for 12–19 mm wet plaster build-ups: nose and wing geometry matches browning-and-set, bonding-and-skim, and sand-and-cement undercoat depths — neither buried by skim nor proud of the finish.
- Wide perforated wings: generous mechanical keying surface for thick undercoat plaster, locking the profile into place through the shrinkage and thermal movement of a multi-coat build-up.
- Reaction to fire A1: the aluminium profile itself meets the highest non-combustible classification — the assembly classification is typically governed by the wider system fire strategy.
- Rigid through the full 3 m: holds plumb and set line under the weight of thick plaster coats applied in multiple passes, with no bowing between fixing points when fixed at 600 mm centres.
Technical Specifications — 3 m Aluminium Wet Plaster Bead Data
| Property | Value |
|---|---|
| Length | 3,000 mm |
| Material | Extruded aluminium alloy, corrosion-resistant |
| Suitable plaster depth | 12–19 mm total finished depth (multi-coat wet plaster) |
| Internal angle | 90° |
| Wings | Perforated for mechanical plaster keying |
| Reaction to fire | A1 (profile classification; assembly subject to system fire strategy) |
| Standard reference | BS EN 13914-2:2016 · BS EN 13658-2:2005 (subject to system confirmation) |
| Primary application | Internal — multi-coat wet plaster on masonry, block, and concrete |
| Fixing method | Plaster dabs at max 600 mm centres or non-corrosive mechanical fixings |
| Application temperature | +5 °C to +30 °C (air and substrate) |
| Storage | Dry, away from acidic atmospheres and de-icing salts |
| Pack | Single 3.0 m length (trade pack quantities available) |
Dimensional data reflects the standard 12–19 mm wet plaster class for aluminium angle beads. Confirm against the current manufacturer datasheet for warranty-critical or specification-governed work.
How the Wet Plaster Aluminium Bead Installs Into a Multi-Coat Plaster System
The bead is bedded into the undercoat plaster ahead of the main wall coat. Apply dabs of the same undercoat material to each wing at maximum 600 mm centres, press the profile square to the corner, and check plumb across the full 3 m with a long spirit level before the dabs begin to grip. The plaster squeezing through the wing perforations forms the primary mechanical bond, so each dab needs to spread across the perforation pattern rather than sit as a single button on the wing face.
Once the bead is set, the main undercoat is applied across the full elevation and ruled off to the nose as the depth gauge, within the open time of the undercoat material. The finish skim follows once the undercoat has reached the correct suction. The full sequence — including stop bead and bellcast detailing at terminations — is set out in the step-by-step corner bead installation guide for UK projects, and corner-and-reveal detailing across complete elevations is covered in the render detailing guide for windows and doors.
Installation Notes — Conditions, Fixings, Cutting
Work within +5 °C to +30 °C ambient and substrate temperature, and confirm the background is sound, clean, and free of loose material before bedding the bead. Cut to length with metal tin snips or a fine-toothed hacksaw, and deburr the cut end with a file before fitting so joints butt tightly without standing edges.
Where mechanical fixings are needed in addition to plaster dabs — typically on hard, low-suction backgrounds — use stainless steel or aluminium-compatible fasteners. Galvanised nails create a bimetallic contact point with the aluminium profile that can accelerate localised corrosion at the fixing under damp conditions, which is exactly the failure mode the aluminium specification is chosen to avoid in the first place.
What UK Plasterers Do Differently With Aluminium Wet Plaster Beads
- Fix at seven points per 3 m run, not four: on a 3 m length, dabs at 600 mm centres give seven fixing points and prevent the bead deflecting under the weight of a thick browning coat between widely spaced supports.
- Specify aluminium for the room, not the building: a heated, well-ventilated lounge may run galvanised beads for decades without issue; the kitchen, bathroom, and basement on the same job benefit from the aluminium upgrade where drying-phase moisture lingers.
- Check plumb at each intermediate dab, not just the ends: a long spirit level and a steady push at each dab position locks the line in before the undercoat closes over.
- Butt joints tight and plaster continuously across: at horizontal joints on taller walls, a tight butt with a continuous plaster pass over the join reads as one uninterrupted arris under decoration.
Is the Wet Plaster Aluminium Corner Bead Right for Your Project?
- Traditional multi-coat internal wet plaster at 12–19 mm total depth: the primary use case — aluminium construction removes the rust-bleed failure mode of galvanised steel during the plaster drying phase.
- High-moisture internal rooms — kitchens, bathrooms, wet rooms, vaulted basements: the correct metal specification where ventilation is limited and moisture lingers in the plaster after application.
- External render corners on facade systems: the external corner aluminium 3.0 m is the matching profile, dimensioned for outdoor render build-ups with UV and weather exposure considered.
- Internal skim coats at 2–3 mm on plasterboard: the PVC L250 plastering corner is the correct thin-coat profile — this wet plaster bead would stand proud of a skim-only finish.
- Drier internal plastering where PVC is acceptable: the 6 mm PVC corner bead is a cost-effective alternative where corrosion resistance is not the governing factor.
FAQ — Wet Plaster Aluminium Bead Specification and Installation
Why specify aluminium over galvanised steel for internal wet plaster?
The drying phase of freshly applied wet plaster is highly alkaline and moisture-saturated, and that is exactly the environment in which a zinc coating on galvanised steel begins to fail. In a well-ventilated room the risk is low; in a kitchen, bathroom, or basement the moisture lingers for weeks and the zinc starts to attack before the plaster has cured, producing rust bleed at the arris within a few years. Aluminium resists alkaline attack during this phase, which is why it is the preferred specification for damp internal rooms.
Can this bead be used on external render corners?
This profile is sized for internal wet plaster at 12–19 mm depth — the nose geometry and wing dimensions are matched to browning and bonding coat thicknesses, not external render build-ups. For external corners on render systems, specify the external-grade corner aluminium 3.0 m, which is dimensioned for outdoor render depths and the exposure conditions of a UK facade.
What fixings are compatible with aluminium bead?
Use stainless steel nails or aluminium-compatible non-corrosive fixings when mechanical pins are required. Galvanised nails create a bimetallic contact between zinc and aluminium that can drive localised corrosion at the fixing point under damp conditions — undoing the durability advantage of choosing aluminium in the first place. Plaster dabs at maximum 600 mm centres remain the preferred fixing method on backgrounds with adequate suction.
How is the aluminium bead cut to length on site?
Cut with metal tin snips for clean, fast trims, or a fine-toothed hacksaw for square, accurate ends at long lengths. Deburr the cut with a file or fine abrasive paper before fitting so the butt joint sits tight without a standing edge, and check the cut piece is plumb across the full run before the dabs grip.
Can the bead be used where the finish is a 2–3 mm skim coat only?
At 2–3 mm skim depth, the nose of this wet plaster bead would stand proud of the finished surface — it is sized for total plaster depths from 12 mm upwards. For skim-only finishes on plasterboard, the PVC L250 plastering corner is the matched profile, with a thinner arris dimensioned to finish flush at standard skim coat thickness.
How many beads are needed for a typical UK room?
A standard UK storey-height internal corner runs around 2.4–2.7 m, so one 3 m bead covers one corner with the offcut available for short reveal returns. A typical bedroom with one chimney breast or partition wall return will use two to four beads; a full re-plaster of a four-bedroom house tends to land in the 25–40 bead range depending on the number of openings and partitions. Order with a small overage to allow for cutting tolerance and any deburred ends discarded during fitting.