JCW Acoustic Impactalay Plus

high performance and versatile acoustic matting

JCW Acoustic Impactalay Plus is probably one of the quickest, most effective and economical high performance acoustic overlay mat solutions available.

It’s an all-in-one product solution, comprising three soundproofing layers that together dramatically reduce both impact and airborne noise from things like footfall, loud talking, music and other airborne sounds.

It’s made from an acoustic foam resilient layer sandwiched between 2 layers of weight enhanced acoustic barrier mat.

Initially designed as an underlay matting to combat impact noise and increase airborne sound insulation on timber floors, it can also be successfully used on concrete floors. This product is highly recommended where a superior level of noise control is required.

Installing this product over a timber floor usually means there is no need to go to the additional expense and disruption of installing false floors or walls.

Because this product is so effective and yet slim, there is minimal loss of floor to ceiling height.


JCW Acoustic Impactalay Plus features an acoustic foam resilient layer sandwiched between and laminated to 2 layers of acoustic barrier mat.

At the same time as acting as a superb carpet underlay, the acoustic foam of the central resilient layer will not harden and crumb like lower quality underlay, bouncing back from impact pressure every time, and de-coupling the floor from the carpet to deny sound transfer.

Product summary and benefits

  • All in one product with excellent impact and airborne sound reduction
  • Incredibly cost effective solution
  • No need to lift floorboards
  • Works superbly on timber and can also be used on concrete floors
  • Ideal as a quality carpet underlay
  • Works in all types of room and dwelling (widely used in new build, refurbishment, change of use, conversions, commercial and residential apartments)
  • Minimal impact on available floor to ceiling height – at just 15mm thick
  • Suitable for all final floor finishes
  • Meets and easily exceeds acoustic requirements of Building Regulations: Approved Document Part E (England & Wales) and Section 5 (Scotland)
  • Supplied in easy to handle, lay and install slab form. Easy to cut and shape

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    Technical Specifications


    • Standard size: 1200mm x 600mm x 15mm
    • Standard density: 17.083 kgs per m2
    • Sheet or slab weight: 20.5 kgs

    Acoustic Performance

      Impact Sound Insulation/Timber Floors Airborne Sound Insulation/Timber Floors
    JCW Acoustic Impactalay Plus 39 dB 51 dB
    Building Regulation minimum requirement 64 dB 43 dB


    For full details of acoustic performance requirements for “dwelling houses and flats” and “rooms for residential purposes” go to Building Regulations Acoustic Requirements.

    Ancillary products

    • JCW Waterproof PVA Adhesive
    • JCW Acoustic Sealant and Applicator Gun
    • JCW Impactalay Plus Perimeter Gripper Strip (9mm thick x 30mm wide x 1m long)
    • JCW Impacta Adhesive

    At a glance guide to calculate what you’ll need when ordering JCW Acoustic Impactalay Plus

    You can quickly work out how much soundproofing products and ancillaries you’ll want if you use this Product Selector to calculate things. Check the square metre dimensions of the area to be treated and apply to the tables below

    Floor Area in m2
    JCW Impactalay Plus (sheets/m2) JCW Spray on Contact Adhesive JCW Impactalay Plus Perimeter Gripper Strip
    JCW Waterproof PVA Adhesive
    1 1 (1.2) 1 1 1
    2 2 (2.4) 1 1 1
    3 3 (3.6) 1 2 1
    4 4 (4.8) 1 3 1
    5 5 (6.0) 1 4 1
    6 5 (6.0) 1 5 1
    8 7 (8.4) 1 6 1
    10 9 (10.8) 1 7 2
    15 13 (15.6) 1 9 2
    20 17 (20.4) 1 12 2


    Remember, you may need to add extra materials to cope with mistakes and mis-measures, so we advise you think seriously about allowing for wastage and off-cuts.

    DIY Installation Guide for JCW Acoustic Impactalay Plus soundproofing mat

    Incorrect installation techniques and materials can compromise the integrity of any acoustic solution. Please follow this general guidance to avoid any incorrect installation which could have an adverse effect on acoustic performance.

    • Step 1: Remove all existing floor coverings.
    • Step 2: Once the carpet or other floorcovering is removed, concrete and other types of solid floor are easy to identify. If the revealed floor however is timber, check whether it is a traditional timber tongue and grooved floor by inserting a thin, sharp object, like a small screwdriver or thin bladed knife through the gap between the boards. If the knife goes through easily without resistance, the floor boarding used will be “butt” or “square jointed”. Any gaps will firstly need to be filled with JCW Acoustic Sealant to avoid noise leakage through and into/out of the room. This step must be done before proceeding to lay JCW Acoustic Impactalay Plus and JCW Impactalay Plus Gripper Strip. Step 2 is not relevant if the floor to be treated is concrete or if the existing floor is a traditional timber tongue and groove make-up, although it is still advisable to seal any significant gaps between the flloorboards with JCW Acoustic Sealant at this stage.
    • Fitting over concrete and suspended timber floors as Carpet Underlay using standard Gripper Rods
      Glue JCW Impactalay Plus Perimeter Gripper Strips around the perimeter of the room. Nail carpet gripper rods in place on top of the Gripper Strip, taking care not to compress the Gripper Strip.Loose lay JCW Acoustic Impactalay Plus sheets in brick bond pattern and tightly bond against the Gripper Rod/ Gripper Strip. Take care to ensure there are no gaps between the JCW Acoustic Impactalay Plus sheets.

    • Fitting under Vinyls or Bonded Carpet
      Bond JCW Acoustic Impactalay Plus to the sub floor in a brick bond pattern using JCW Impacta Adhesive. Sheets should be butted up to the perimeter wall/skirting.Then adhesive bond a layer of 9mm tongue and groove (t&g) MDF on to the JCW Impactalay Plus taking care to ensure that the joints do not coincide. Bond the t&g joints using JCW Waterproof PVA Adhesive. Leave a minimum isolation gap of 5mm between the MDF layer and the perimeter wall to avoid flanking sound transmission. When all the sheets have been laid, fill the 5mm gap with JCW Acoustic Sealant.
    • Fitting under Timber Floor Finishes
      JCW Acoustic Impactalay Plus can be used under timber floor finishes but its suitability should be confirmed with the floor finish manufacturer before installation.
      If the manufacturer or installer considers that movement underfoot could be excessive, use a 9mm t&g MDF or 6mm butt-jointed plywood layer (follow steps as in Vinyls or Bonded Carpets guidance above).
    • Fitting on Stairs
      Cut the JCW Acoustic Impactalay Plus to the correct size and bond to the stair tread (and riser) as required using JCW Impacta Adhesive. Use JCW Impactalay Plus Perimeter Gripper Strip and gripper rods where necessary. Where a nosing detail is specified, fit a 15mm thick section of timber under the nosing to ensure the correct height.
    • General use under units, fixtures and fittings
      When kitchen or bathroom units need to be fixed to the floor they should be mounted on to a 15mm timber plinth and the JCW Acoustic Impactalay Plus butted up to the plinth. This will ensure a consistent floor height.

    Note: Before using any adhesives or other bonding materials to fix your choice of final floor finish to the JCW Impactalay Plus, please refer to the manufacturers recommendations and guidance. Use only those products recommended by the manufacturer that are considered suitable. When in doubt, contact the manufacturer.

    Professional Installation Service available

    For customers who need or prefer it, Soundproofyourhome offers a professional acoustic installation service across the UK.

    Our skilled and experienced tradesmen understand acoustic materials and how to fit them quickly and correctly.

    The result is a cost effective service and peace of mind about the acoustic integrity of your project. Contact us today for a free quotation.

    Soundproofyourhome is the domestic market operations division of JCW Acoustic Supplies Ltd, the UK’s leading manufacturer and distributor of soundproofing, sound insulation and sound absorbing products.

    Sound advice from Soundproofyourhome:

    Contact us today and tell us more about the noise problems you are experiencing. Our friendly, helpful advisors will offer you the most appropriate acoustic solutions available to meet your acoustic needs and budget from our comprehensive range.

    We believe talking about your situation and offering sound advice based on our vast experience in the acoustics business is a more reliable way of solving your noise problem than simply taking your order or selling “off the screen”, as some companies do.

    And if you are in any doubt about issues associated with soundproofing, like weight of materials, structural strength or meeting Building Regulations, then please talk to us – we’ll be happy to help.