SonaSpray K-13 Special

SonaSpray K-13 Special

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Spray applied seamless one coat decorative acoustic ceiling & wall finish
  • Easily applied to flat or curved surfaces
  • Reduction of noise reverberation
  • Rain on roof noise reduction
  • Thermal insulation and condensation control
  • K-13 Special acoustic ceiling finish typically provides these features at lower installed prices than fixed panel systems
  • Build Regs. part ‘E’ & BB93 compliant, to be used to reduce reverberation

SonaSpray K-13 Special acoustic ceiling & wall finish is spray applied directly to most substrates: concrete, plasterboard, GRP, steel, glass, expanded polystyrene etc. and will maintain its fire rating.

Domes, vaults, profile, corrugated, flat etc.  Almost any shaped substrate can be sprayed with SonaSpray K-13 Special acoustic ceiling & wall finish.

Office Acoustics

  • Carbon neutral
  • Low embodied energy
  • Good for the environment
  • Recyclable

Naturally safe recycled cellulose fibre.  Reconstruction of a building may necessitate removal of SonaSpray cellulose fibre acoustic ceiling.  It can be recycled or disposed of as a non-special waste to landfill and your local authority waste disposal will give advice on recycling.

Reception Acoustics

Different acoustic finishes available

Available in a range of standard colours from stock, SonaSpray K-13 Special acoustic ceiling spray can also be manufactured to the client’s colour requirement [minimum quantity applies].

SonaSpray K-13 Special is a total acoustic ceiling & wall finish system, with in-built treatment for fire and mould resistance; coloured through the full thickness of the coating. Manufacture is accredited ISO 9001:2000 certification.

SonaSpray K-13 Special acoustic ceiling spray was developed for installations where the standard SonaSpray K-13 surface was considered to be too coarse. It has a finer texture and is an attractive surface finish in new build and renovation projects.

Should finer acoustic ceiling & wall finishes be required, please see the rest of the range including the smoothest acoustic ceiling & wall finish available.  The excellent sound absorbing qualities of the SonaSpray range allows designers to utilise smaller areas for effective noise reverberation control and improved ambient sound quality.

“Following the recent installation of nearly 3,000m2 of SonaSpray K-13 Special to the corridors, classroom and activity hall ceilings plus an extra 200m2 of works to the main sports hall at  St. Pauls Way Community School, Bouygues UK Ltd would like to thank Oscar Acoustics for their hard work in delivering a high standard of work within our programme, for which speed of installation was critical. 

Your site teams should be commended on the professional manner in which they conduct themselves. We found them to be extremely helpful and knowledgeable whilst keeping comprehensive day to day records of events.  They kept a 100% health & safety record for the duration of the project, passing unannounced inspections from an independent health & safety company organised by yourselves. We are delighted with the appearance of the finished SonaSpray K-13 Special product and the performance that it provides; so too is our client.  It passed all regulation testing first time.  We would also like to thank Oscar Acoustics for their over and beyond acoustic technical advice on our project which meant the need for outside acoustic consultancy was kept to a minimum.  We  have  recommended you for further Bouygues UK projects and look forward to continuing our working relationship with Oscar Acoustics."

Chris Stevens
Managing Director, Bouygues UK
5 star review rating  

Excellent noise control within large building spaces

SonaSpray K-13 Special acoustic ceiling & wall finish is a popular choice in a wide variety of large spaces such as sports and other large hall facilities, school drama studios, television and sound studios, airports, railway stations, swimming pools and entertainment venues.  In fact any indoor space where noise reverberation is a problem. 


Visit our Acoustic Projects page for more information on SonaSpray acoustic spray installations throughout the UK.


Patented adhesives provide unequalled bond strength allowing application thickness of up to 32mm in one application (see SonaSpray K-13 for thicker applications).


See our full range of acoustic decorative finishes from textured to the smoothest available

School Acoustics

"I'd just like to convey my utter delight and relief at being able to use the new large hall. It was literally visible this evening, how our Beaver Scouts calmed as they moved from the small hall to the larger, more peaceful room.  Thanks to you we had one of our best ever indoor activities.  It was calm, fun and enjoyable for all.  Thank you so much, I am only vaguely aware how much work you have put into this project, and want to make sure you know how much we appreciate it.

Well worth the money!"

The Beaver Scout Team and Wye Village Hall committee

5 star review rating

SonaSpray K-13 Special Installations

UCL Torrington

UCL Torrington

With its student population increasing rapidly, University College London (UCL) required more space on its campus in Bloomsbury.  Working with the University’s Design Team, Structure Tone helped develop a scheme to refurbish the ground floor and basement and also renovate Level 10 at Torrington Place.  

Chisenhale Gallery Acoustics

Chisenhale Gallery Acoustics

SonaSpray K-13 Special in white applied directly to the concrete soffit at Chisenhale Gallery, London to control reverberation for perfect gallery acoustics. 

YRM Architects’ Studio, Kings Cross, London

YRM Architects’ Studio, Kings Cross, London

Office acoustics are a hot topic at the moment within the design and build industry as more and more designers and architects recognise that good acoustics really are essential to creativity and productivity within the workplace. Working in a uncomfortably noisy space for long periods of time can lead to unnecessary stress and work related frustrations. Trying to concentrate or have a conversation with someone over the phone can feel near on impossible when you can barely hear yourself think in such a sonic battleground.

Le Pain Quotidien Restaurant, London

Le Pain Quotidien Restaurant, London

Oscar Acoustics K-13 Special acoustic ceiling spray was applied for Du Boulay Contracts in white to control reverberation and decorate the existing rib deck at the Le Pain Quotidien Restaurant in Monument, London.

St. Paul's Way Community School

St. Paul's Way Community School

Throughout the construction of St. Pauls Way Community School in London's Tower Hamlets, Oscar Acoustics assisted Bouygues UK with their school acoustic ceiling requirements. 3,000m2 of SonaSpray K-13 Special was applied to light wells, corridors, balconies & the activity hall resulting in easy 1st time compliance with BB93 testing.

Hope Academy - Wilmott Dixon

Hope Academy - Wilmott Dixon

Hope Academy in Newton-Le-Willows was a BSF design and build project by Willmott Dixon. Outside acoustic consultation lead to Oscar Acoustics’ SonaSpray FCX being specified for the impressive giant feature, yellow pods in the main dining space, SonaSpray K-13 Special in light and dark grey for the auditorium walls and SonaPanel acoustic panels for the main sports hall upper walls.

Penarth Pier Pavillion

Penarth Pier Pavillion

For excellent gallery acoustics, the designers incorporated our SonaSpray K-13 Special, a spray applied seamless one coat decorative acoustic ceiling & wall finish at 16mm in white for the main gallery area and in black for the cinema theatre.

Sevenoaks Prep. School

Sevenoaks Prep. School

Sevenoaks Preparatory School is an Independent, Primary School in Godden Green, Sevenoaks.

In 2005, work was completed on a new school hall. This was intended to be used for sports lessons, assemblies, school, drama productions etc. It soon became apparent that due to poor school acoustics, the new hall was unfit for purpose.

Harpurhey Leisure Centre

Harpurhey Leisure Centre

At the Harpurhey Leisure Centre swimming pool, acoustic design calculations demonstrated there would be a problem with speech audibility in the pool area due to high levels of noise reverberation. Oscar Acoustics was employed to apply 16mm of SonaSpray K-13 Special to the soffit in white. 

SonaSpray K-13 Special Technical Specification

   Download BIM Object

Acoustic DATA:

Where noise reverberation is a problem SonaSpray K-13 special acoustic ceiling and wall finish can be tailored to meet your specific project acoustic needs.  There is a choice of finish; you may select texture, colour and acoustic performance.  SonaSpray K-13 Special acoustic ceiling and wall finish can be applied at variable thickness and variable area to provide a designed acoustic ambience.  It is spray applied to the full thickness in one application.

SonaSpray K-13 Special absorption coefficients

in mm
12.5mm 0.09 0.22 0.58 0.79 0.88 1.04 0.65
16mm 0.10 0.35 0.83 0.88 0.99 1.04 0.75
19mm 0.10 0.35 0.87 0.87 1.03 1.07 0.80
25mm 0.14 0.54 0.93 1.03 1.08 1.05 0.90
32mm 0.18 0.60 0.98 1.03 1.04 1.05 0.90

Test DATA certified by TNO Technical University Delft NL.  SonasSpray acoustic ceiling and wall finish tests were on a solid backing.  A panel backing with air space behind the panel will change absorption; normally there is improved absorption at low frequency.


SonaSpray K-13 acoustic ceiling and wall finish achieves M1 certification for Building Materials emissions.  This is the best possible classification.  Click here for certificate.

Thermal DATA

SonaSpray acoustic ceiling and wall finish insulates by creating dead air spaces macroscopically between and within the hollow cellulose fibres.  Testing on actual buildings demonstrates that sprayed insulation outperforms fibreglass bats that are mechanically retained. 

100mm thick U = 0.32 W/m2K


Dry Weight of SonaSpray Special K-13 per 10mm thickness = 0.90 kg/m2

Wet Weight of SonaSpray Special K-13 per 10mm thickness = 1.72 kg/m2

Dry Weight of SonaSpray K-13 Special per 20mm thickness = 1.80 kg/m2

Wet Weight of SonaSpray K-13 Special per 20mm thickness = 3.44 kg/m2

Bonding to substrate

SonaSpray K-13 Special acoustic ceiling and wall finish can be applied to virtually any substrate; some surfaces may need priming to control suction.  Old surfaces may need a barrier coating to prevent staining from leaching out contaminants while the surface is wet.  Fully cured SonaSpray K-13 Special will improve strength as well as reducing noise reverberation.

Condensation control

For areas such as indoor pools and ice arenas, SonaSpray K-13 Special acoustic ceiling and wall finish aids in not only noise reverberation control but condensation control and cold bridging.  The proper combination of SonaSpray K-13 Special and ventilation prevents condensation on metal, concrete and other similar surfaces.  SonaSpray K-13 Special actually reduces ventilation requirements, saving in both the ventilation equipment cost and operating costs.

RH control:

SonaSpray K-13 Special acoustic ceiling and wall finish is a natural humidity moderator.  At times of increasing humidity SonaSpray K-13 Special will absorb large amounts of water vapour.  When the humidity drops SonaSpray K-13 Special will exhale water vapour and maintain a balance.  This characteristic promotes a healthy atmosphere.


The adhesive used with SonaSpray K-13 Special acoustic ceiling and wall finish provides a strong, durable and resilient bond.  When fully cured, surface strength of old plaster will typically improve.

Recessed Items

Recessed services e.g. spot lighting will require a halo spacer to match the material depth.  Oscar Acoustics manufacture and install stainless steel halo spacers to the same size as the hole cut out.  Stop beads may be required around openings which again we can supply and install.  Specially designed access hatches are also available through Profab, enabling the SonaSpray to continue across the hatch door.  Problems can arrise from using other hatches.  These items are at extra cost and are to be purchsed direct from the Profab.  Please contact Oscar Acoustics for details and an item code.  Surface mounted fittings e.g. hanging/pendant lights will require pattresses to match the material depth.  Please contact Oscar Acoustics for further advice.

Please Note:  90% of flangeless fittings do not work properly with any acoustic finish.  If you are specifying a flangless fitting, please contact Oscar Acoustics for advice.

Where to use

SonaSpray K-13 Special acoustic ceiling and wall finish can be quickly and effectively applied to any prepared surface and construction configuration where noise reverberation is a problem.  This allows minimum working down time in existing structures with abilities to meet critical deadlines in new construction.  SonaSpray K-13 Special has a medium surface texture and is suited to reducing noise reverberation in large rooms and halls.  When applying to walls, position acoustic finishes above head height.  For lower walls or areas of high impact, see EchoCheck acoustic blocks or Oscar Evo-Panels.

Other SonaSpray products offer a finer surface texture.

Fire performance ratings

UK Fire test by Warrington Fire Research:
Class 1 to BS476 Part 7
Class 0 to BS476 Part 6

European test by Warrington Fire Research:

USA – Factory Mutual Standards research corp. approvals: category I, II, III, IV and V:

Category I: As an interior finish material of low fire hazard [class I building material] over non-combustible surfaces not requiring automatic sprinkler protection in and of itself.

Category II: As a protective coating to delay the ignition and reduce the surface burn rate of combustible wood and cellulosic fibre building material.

Category III: As a protective coating to delay the ignition and reduce the surface burn rate of low melting point, combustible cellular plastic building materials and to protect their dimensional stability for a brief period.

Category IV: As a protective coating for building structural steel to supplement automatic sprinkles protection in preventing structural failure temperatures of the steel in high fire hazard occupancies.

Category V: As a protective coating to the underside of a Class II insulated steel roof deck construction, to sufficiently lower the rate of fuel contribution from the Class II deck components to qualify the construction as Class I, so allowing automatic sprinkler protection to be omitted under Factory Mutuals Standards .


SonaSpray K-13 Special acoustic ceiling and wall finish can be over-painted (consult Oscar Acoustics technical department before painting as noise reverberation controlling properties can be significantly reduced if applied incorrectly), or applied with additional coats of SonaSpray.  Small areas of damage can be repaired by hand.

If SonaSpray K-13 Special acoustic ceiling and wall finish is disturbed or damaged so that fibre is released into the atmosphere, the resulting contamination is harmless.  Maintenance work can be undertaken while the building is occupied.  Please refer to COSHH data for detailed product analysis.

SonaSpray is manufactured by ICC, Houston, Tx 
ISO 9001: 2000 certification

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