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Seamless acoustic plaster ceiling meeting a wall with no visible joint
Specification and technical data

Acoustic plaster — specification and technical data

A seamless sound-absorbing ceiling and wall surface with no grid, no tile and no visible joint. Absorption is a property of the whole build-up — board thickness and mounting type change the figure, so specify the system, not the finish alone.

The system

What sits against what, from the substrate outwards. Junctions, movement joints and edge details are project-specific — send us the drawings and we will mark them up.

Fellert Even Better — hand-applied system

Absorption quoted for type A mounting. The 39 mm board reaches absorption class A on the standard finishes.

BUILD ORDER — SUBSTRATE FIRST, IN SEQUENCE Substrate
16 mm gypsum wallboard, metal ceiling grid at 400 mm centres, concrete, or a previously painted substrate.
 Acoustical board
25 mm (1") or 39 mm (1.5") board, 60% recycled content, adhered with Even Better Board Adhesive or fixed mechanically with Spring Washers.
 Acoustic plaster
Even Better 1 at approx. 3 mm wet, or Even Better 2 at approx. 1.5 mm wet for the Silk finish. Perlite and recycled cotton, 40% recycled content.
 Acoustical coating
Sprayed in two light passes with an air-mix gun. Carries the colour without reducing absorption.

Straight Up — drywall-method system

Built and finished like a drywall ceiling. Designed to be demounted and re-used.

BUILD ORDER — SUBSTRATE FIRST, IN SEQUENCE Grid
Drywall suspension grid at 300 mm centres (metric) or 16" centres (imperial).
 Acoustical board
800 × 1,200 mm at 20 mm, or 600 × 1,200 mm at 15 mm. High-NRC backer board where type A mounting is required.
 Plaster and scrim
Straight Up 1 basecoat, scrim reinforcement, then Straight Up 2.
 Colorant and coating
One box of colorant per 50 m² of system, then the acoustical coating.

Performance data

Taken from the manufacturers' own technical data sheets, with the standard each figure was measured against. Product-level figures are on the product pages below.

Property Result Standard
Sound absorption, Straight Up 20 mm NRC 0.75 type A · 0.85 type E200 · 0.80 type E400; up to NRC 0.95 with the high-NRC backer ASTM C423
Sound absorption, Straight Up 15 mm NRC 0.65 type E200 · 0.55 type E400; up to NRC 0.85 with the high-NRC backer ASTM C423
Sound absorption, Fellert Even Better NRC 0.80 – 0.95 at 39 mm on the standard finishes; NRC 0.60 on Marble and Stone ASTM C423, type A mounting
Absorption class alphaW up to 0.95, class A, at 39 mm EN ISO 354 / EN ISO 11654
Ceiling attenuation class CAC 51 (Straight Up 15 mm) ASTM E1414
Reaction to fire Class A to ASTM E84; B s1d0 or A2 s1d0 to EN 13823 depending on the build-up ASTM E84 / EN 13823
Light reflectance Up to 93 ASTM 1477
Volatile organic compounds 0 g/l over 15 – 39 mm (Straight Up 20 mm); CDPH v1.2 compliant CDPH/EHLB Standard Method v1.2-2017
Mould growth resistance Meets the specification requirements ASTM D3273 / ASTM D3274
Recycled content Up to 92% by weight (Straight Up 15 mm); more than 50% (20 mm); 40% plaster and 60% board (Fellert) Styjl data sheets
Thermal resistance R 4.55 at 25 mm; R 6.82 at 39 mm (Fellert board) Fellert Even Better data sheets

Products in this family

One page per technical data sheet. Each carries the manufacturer's declared figures, the limits, a specification clause and the full document set.

Styjl Fellert Even Better Silk Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. The smoothest of the three standard finishes — a close, even surface. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Sahara Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A fine open texture. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Secern Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A coarse open texture, the most pronounced of the standard three. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Concrete Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A concrete effect, without the loss of absorption the other decorative finishes carry. There is no grid, no tile and no visible joint. Styjl Fellert Even Better New England Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A lined decorative finish. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Silk Metallic Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. The Silk surface carrying a metallic coating. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Marble Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A marble effect. It trades absorption for appearance — specify it where the acoustic duty sits elsewhere in the room. There is no grid, no tile and no visible joint. Styjl Fellert Even Better Stone Seamless acoustic plaster A hand-applied seamless sound-absorbing ceiling and wall system: an acoustical board of recycled fibre, an acoustical plaster of perlite and recycled cotton, and an acoustical coating that carries the colour. A stone effect. Like Marble it trades absorption for appearance. There is no grid, no tile and no visible joint. Styjl Fellert Even Better 1 Acoustic plaster Acoustic plaster made from recycled cotton fibres and perlite. The base coat under every Even Better finish, and the top coat for the Sahara and Secern finishes. Sprayed and trowelled at approximately 3 mm wet. Styjl Fellert Even Better 2 Acoustic plaster Acoustic plaster made from recycled cotton fibres and perlite, used as the top coat for the Silk finish. Sprayed and trowelled at approximately 1.5 mm wet. Styjl Fellert Even Better Acoustical Coating Acoustic coating A water-based coating for acoustic ceilings that carries the colour. Applied correctly it does not reduce the acoustic absorption of the ceiling beneath it, which is what separates it from ordinary paint — and it is the route to restoring an existing acoustic ceiling rather than replacing it. Styjl Straight Up 20 mm Seamless acoustic ceiling and wall system Styjl's current system, built and finished much like a drywall ceiling but absorbing sound across the whole surface. Smooth, non-directional and monolithic, with no grid and no visible joint. Designed to be demounted and re-used rather than demolished. Styjl Straight Up 15 mm Seamless acoustic ceiling and wall system The shallower Straight Up build-up, for ceilings where the void will not give up 20 mm. Same seamless, non-directional surface and the same installation method as a drywall ceiling, at up to 92% recycled content by weight.

Where not to use it

Specifying a material into the wrong place is the most expensive mistake on a finishes package. These are the limits we will raise at review whether or not they are asked about.

  • An interior ceiling and wall system. Not a wet-area or external finish.
  • Absorption is a property of the build-up. Board thickness, mounting type and the presence of the high-NRC backer each change the published figure — they are not interchangeable.
  • The Marble and Stone finishes absorb materially less than the standard three: NRC 0.60 against 0.80 to 0.95. Specify them where the acoustic duty sits elsewhere in the room.
  • Straight Up 15 mm has no published type A absorption figure without the high-NRC backer board.
  • Fire classification depends on the set-up and must be confirmed against the specified build-up.
  • Respiratory and eye protection are required when mixing the dry powder products.
Specification clause

Acoustic plaster: Styjl [Straight Up 20 mm / Straight Up 15 mm / Fellert Even Better] seamless acoustic ceiling and wall system, board thickness [25 mm / 39 mm], mounting type [A / E200 / E400], with high-NRC backer board where required, finished [Silk / Sahara / Secern / Concrete / New England / Silk Metallic / Marble / Stone] and acoustical coating in colour [ref] to the approved sample panel. Sound absorption not less than NRC [ref] to ASTM C423. Reaction to fire [Class A to ASTM E84 / B s1d0 to EN 13823]. Supply and application by Conmarble Natural Finishes as exclusive Middle East dealer for Styjl.

Square brackets mark the choices that belong to the project. Send us the finishes schedule and we will return the clause completed, with the sample and mock-up programme against it.

Document library

Every publishable document for this family, reproduced in full and unaltered under our cover. Free to download, no form.

Related systems

Microcement A seamless mineral coating at 2 to 3 mm over a prepared substrate, sealed to a defined system. Microcement is durable and low-VOC. It is a cementitious product: specify it for wear, chemical exposure and continuity, not as a natural or breathable finish. Decorative finishes Italian decorative interior finishes, applied by brush, roller, sponge or trowel over a primed and cohesive substrate. These are decorative coatings rather than mineral plasters: specify them for effect and interior wall surfaces, and prime the substrate properly first.

Technical support for the design team

We supply the material and we apply it, so the specification and the workmanship sit with one party. Send a finishes schedule, an elevation or a mood board and we will come back with the system, the build-up, the sample programme and a completed clause.

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