Skip to content
Call us on 0208 123 9710 | Email us at info@soundstop.co.uk
Call us on 0208 123 9710 | Email us at info@soundstop.co.uk

Phonestar SBx Boards - 15mm

£28.95
Original price £28.95 - Original price £28.95
Original price
£28.95
£28.95 - £28.95
Current price £28.95


  • Superb performance backed by laboratory testing

  • Highly-engineered German flooring product with CE Mark

  • Can be used for walls, floors, and ceilings

These 1200mm x 800mm boards are a superior performance alternative to one of the layers standard acoustic plasterboard due to "fluid mass" contents.


SBx can be used for soundproofing walls, floors and ceilings whether constructed from timber, steel or solid substrate, in new builds, conversions, remedial and refurbishment projects.

SBx boards are an excellent product designed to reduce the transmission of impact and airborne sound between two spaces. The product is our number one choice when trying to improve the soundproofing from noisy neighbours downstairs.

Many customers get confused by the large array of heavy rubber mats on the market which are great at stopping impact sound transmission traveling downwards but are less effective at the more common problem that affects people, that is the airborne sound being transmitted upwards. Due to it's "fluid mass" content, SBx boards can be twice as effective at reducing airborne sound transmission as the heavy 15kg mats available on the market.

38dB (Rw, -5Ctr) Airborne sound insulation, this is manufacturer tested data of the product in isolation, 22dB (;Lw) Impact sound insulation (manufacturer data).

Product Application

SBx Board main applications are in the following:

  • Soundproofing floors
  • Soundproofing ceilings
  • Soundproofing separating walls
  • Soundproofing party walls
  • Soundproofing Home Cinema and Entertainment rooms



SBx Boards are a cross fluted engineered card and hardboard carcass containing a "fluid mass" that is a finely mixed and compacted loose quartz sand mixture, which exhibits high mass and density with unique self-decoupling properties.

SBx Boards are a natural product which are breathable, pollutant free and odourless, the boards are only 15mm thick which avoids problems with door thresholds and re-fitting skirting in refurbishments. They are easy to cut and install with simple butt joints and does not require flanking strips. This makes for a speedy installation time and low cost of labour, or can easily be completed yourself.

SBx boards offer acoustic insulation which also adds thermal mass to lightweight structures it also works seamlessly with under floor heating.

The solution gives comparable sound insulation results to robust floating floors which are a minimum 107mm thick. It provides a solid floor feel underfoot unlike other squashy acoustic floor systems.

Sound insulation performance actually improves by 3dB when a hard surface is fitted on to it and it supports 5kN loading.

This product can be used to very effectively soundproof a floor. Ideally it should be used in combination with 60kg/m3 acoustic mineral wool.

This is a true DIY solution with the only skill necessary being the ability to cut (then tape and seal) the SBx boards.

Technical Data

Phonestar SBx board has been rigorously assessed by various European laboratories and it has a European Technical Approval – ETA 13/0411 – ensuring compliance with Building Regulations Part E for The Resistance to the Passage of Sound. Please note that this is not the case with a number of similar products for which the manufacturer often has done no testing themselves.


Here are the main details for this product:

Dimensions: 800 x 1200mm

Thickness: 15mm

Pack Size: 1 Board

Weight: 18kg/m2

Density: TBC

Coverage: 0.96 sqm

Fire rating: Reaction to fire Class E under EN 13501-1

View Product Information Guide

Visit our Fitting Instructions section for more detailed instructions relating to your specific application.

Please contact our team if you have any questions on this product.

Looking for a complete soundproofing solution?

If your looking for soundproofing for a particular situation or application, then the best place to start is with our soundproofing solutions that cover walls, floors, ceilings and reducing echo. Select the relevant application below to find out more.

Wall Solutions

Floor Solutions

Ceiling Solutions

Echo Solutions

Check out our Echo solutions

If your looking for echo reduction for a particular situation or application, then the best place to start is with our echo solutions.

Echo Solutions

Instructions for use

The SBX board is used in place of a 12.5mm acoustic plasterboard. The product can be screwed in the same way as plasterboard. Cutting and sealing is done in the same way on both 10mm and 15mm SBx boards.

The boards are labelled with a particular side to be facing outwards. This ensures the product lies consistently from board to board.

Where the developer has opted for a traditional 18mm or 22mm tongue & groove overlay then all flooring finishes are treated conventionally and the following instructions are redundant.

Cutting SBx Boards to size

  • Ensure careful handling to minimise filler spillage – otherwise the final performance may be compromised
  • Only cut the SBx boards while it is laid flat
  • Use a straight edge for guidance
  • Cut with a jigsaw, hand saw, Stanley knife or circular saw (ceramic tile tungsten carbide grit jigsaw blade, or general purpose tungsten carbide fine tooth circular saw blade, for longevity)
  • Immediately seal all cut edges with PhoneStar SBx Tape while holding the board upright - See below for more details on using SBx Tape

Watch the SBx boards being installed by professionals:


Fitting Floor finishes over SBx Boards

Here is guidance on installing different floor finishes on top of the SBx boards:

Fitting Solid Wood, Engineered Wood, Parquet & Laminate Floors Directly over SBx boards

a. Wood flooring must be acclimatised in the fitting location prior to fitting for the length of time specified by the flooring manufacturer. This prevents shrinkage, cupping and warping at a later date.

b. Prior to installation, the installer has the final responsibility to inspect the finished flooring as to grade, manufacture and factory finish. The installer must use reasonable selectivity and discard or cut off pieces with deficiencies.

c. It is imperative that the expansion gap is carefully adhered to as this is also necessary to prevent the transmission of sound from the wood flooring to the adjoining walls which in turn would transmit flanking noise. This gap is usually 6mm (12mm when floating) around all vertical objects and the whole perimeter of the room.

Mechanical fixing (usually 6mm expansion gap):

a. Solid wooden flooring must not be nailed directly to SBx boards or through to the sub-deck, which would cause a sound bridge. For ‘Hidden Nail Technique’ glue 9mm (minimum) plywood, OSB or chipboard on top of SBx boards with wood flooring glue. Leave a 6mm gap between the wooden layer and the walls (and any other vertical structures) to reduce vibration and flanking noise.

b. Then nail the timber flooring directly into 9mm top layer only, leaving expansion gaps as per manufacturer’s instructions. Leave a 6mm gap between the flooring and the walls and any other vertical structures. The gap at the perimeter can be sealed with flexible acoustic sealant.

Bonding (usually 6mm expansion gap):

a. If the installer requires the option of being able to remove the wood flooring at a later date without damaging the SBx boards acoustic layer, then a wooden overlay must be laid and bonded to SBx boards - 3mm to 6mm thick plywood is common. It is important to leave a 6mm expansion gap around vertical objects and the whole perimeter of the room.

b. For bonding wooden flooring, use the wooden flooring adhesive as recommended by the flooring manufacturer (usually rubberised wood flooring glue) which should be spread evenly on the floor with a medium notched trowel, as per the flooring manufacturer’s instructions.

c. Always check for an adequate adhesive bond before proceeding.

Floating (usually 12mm expansion gap, 6mm for Laminate):

a. Flooring suitable for fitting as a floating layer, as per manufacturer’s guidance, (usually over 7mm thick), should be laid directly over SBx boards without underlay for the best acoustic performance.

b. It is important to leave a 12mm expansion gap, as recommended by flooring manufacturer, around vertical objects and the whole perimeter of the room. For laminate use the manufacturers recommended 6mm gap.

c. Joint Sealant for laminate flooring can be used to permanently protect laminate from moisture effects, if necessary.

Fitting Ceramic Tiles Directly over SBx boards

a. It is recommended to use marine plywood as your sub floor, if possible.

b. If floor height is not an issue it is recommended to lay a Tile Backing Board or a 6mm Marine (WBP) plywood board over SBx boards which is bonded to SBx boards using a grab adhesive. This will protect the SBx boards acoustic floor should you wish to change the tiles in the future. It is imperative to leave a 6mm expansion gap between the tile backing board / plywood and any vertical objects, as well as the whole perimeter of the room, and fill the gap with a permanently flexible and waterproof sealant, to reduce flanking noise.

c. If floor height is an issue, place a 100mm wide fibre glass mesh ‘scrim tape’ over all SBx boards joints.  Then lay the tiles in a thin bed of rapid setting flexible cement based tile adhesive, suitable for wooden floors.  The scrim tape ensures no movement will take place due to vapour in bathrooms and kitchens. If tiling a wet room, please see the next section.

Fitting Ceramic Tiles Directly over SBx boards in Wet Rooms

a. It is recommended to use marine ply as your sub floor, if possible.

b. SBx boards is moisture resistant and its performance will not deteriorate in these applications. Do not knock boards tightly together - simply lay lightly butted allowing for minimal expansion.

c. In high moisture areas it is important to lay a vapour barrier, or else it is recommended that a Tile Backing Board or a 6mm Marine (WBP) Plywood board should first be laid and bonded over SBx boards using a grab adhesive.   It is imperative to leave a 6mm expansion gap between the tile backing board and any vertical objects, as well as the whole perimeter of the room, and fill the gap with a permanently flexible and waterproof sealant, to reduce flanking noise.

Fitting Carpet Directly over SBx boards

Carpets requiring an independent underlay:

a. SBx boards are not an ‘underlay’; a good quality carpet underlay is still required to protect the carpet and SBx boards.

b. Carpet grippers can be bonded to SBx boards in the same manner as for solid concrete floors; using a rapid set grab adhesive recommended for carpet grippers.  Carpet tacks or nails ( if used ) are hammered through the carpet and into the carpet gripper - however it is imperative that these nails do not pass through into the sub-deck below. Common carpet gripper nails are insufficient length to pass through the SBx boards, but it is the installer’s responsibility to confirm this on site. Ideally there should not be penetrations through the carpet gripper but further screws can be added to support grippers as long as they don't exceed 500mm centres. What should be avoided is multiple penetrations though the board over a small area.

Carpets with a pre-bonded foam or felt underlay:

a. These carpets usually incorporate a thin foam or felt backing, insufficient to spread point pressure load, and therefore require a 3mm to 6mm plywood bonded to SBx boards prior to fitting the carpet.

b. The plywood is bonded to the SBx boards leaving a 6mm expansion gap around all vertical objects and the whole perimeter of the room, which can be filled with permanently flexible acoustic sealant.

c. Foam backed carpets should always have a brown building paper laid prior to fitting which prevents the foam from sticking to the floor when its glue seeps out.

Fitting Linoleum & Vinyl Directly over SBx boards

a. Linoleum or Vinyl cannot be fitted directly on the surface of SBx boards.  For commercial applications use a hard Linoleum and Vinyl subfloor system floating over SBx boards or 6mm plywood bonded to SBx boards. For domestic applications, bond 3mm to 6mm plywood or similar to SBx boards.

b. The plywood is bonded to the SBx boards leaving a 6mm expansion gap around all vertical objects and the whole perimeter of the room, which can be filled with permanently flexible acoustic sealant.

Sealing a Cut SBx Board

Whenever the cut edge of the board is exposed the SBX sealing tape should be used to prevent silica leakage, here are basic instructions for sealing the cut boards:




Visit our Fitting Instructions section for more detailed instructions relating to your specific application.

Check out our Soundproofing Guides for more information, advice and tips on all aspects of soundproofing.

Don’t forget your SBx Board Sealing Tape!

Don’t forget your SBx Board Sealing Tape!

Whenever the cut edge of the board is exposed the SBX sealing tape should be used to prevent silica leakage.

Shop SBx Tape