Acoustic Joist Cap

Easy to install impact isolation strip that sits on-top of the joists. Very good performance for minimal height rise.

Supplied in packs of 50 strips (100 lin. m).



Acoustic Joist Cap

Acoustic Joist Cap is a superb, easy to fit, Direct To Joist System.

Engineered as a Part E compliant acoustic joist treatment, to save the developer time and money. It can be used in both new build and refurbishment projects for timber and masonry builds.

This product, used upside down, can also provide the resilient layer required for customers to make up their own resilient battens.

If the product is used in this manner, on a concrete floor, impact improvements in the order of: :
Delta Lw22dB with a standard batten.
Delta Lw24dB with a deep batten can be expected.
Robust Details only require an improvement of Delta Lw17dB.

If the product is used in this manner, on a timber floor, improvements in the order of:
Delta Rw+C;tr14dB and
Delta Lw20dB can be expected.
Robust Details only require an improvement of:
Delta Rw+C;tr13dB and
Delta Lw15dB.

General Physical Data
Length: 2m
Width: 50mm (but will fit up to 60mm wide joist)
Thickness: 14mm
Density: 30kg/m³

Proven to be the most effective means of achieving superior sound attenuation, the mass of the structure is placed above the resilient layer. The product is then simply placed over the joists before the mass of the floor is added. The cap is suitable for both rough-cut and planed timber joists.

Installation Guide
  • Care should be taken to comply with all relevant safety and building regulations.
  • The joist cap can be fitted from either above or below the joists and even before the joists are fitted.
  • The jaws of the caps are slightly tapered to ensure a tight friction fit. Simply open the jaws and sit the cap over the joist ensuring the base is located tightly with the joist surface.
  • In all applications, our perimeter isolation strip must be used so the floating floor is fully isolated from the structural floor and walls.

Incorporating the latest changes to the Approved Document E 2003, the minimum and maximum sound insulation requirements for separating floors are as follows:

Airborne Sound Reduction DnTw+C;tr Impact Sound Level LnTw
Conversion 43dB or greater 64dB or less
New Build 45dB or greater 62dB or less

Acoustic Joist Cap

  Airborne              Impact
Rw=63dB (Ctr-12)    Ln,w55dB
Rw+ Ctr= 51dB

Acoustic Joist Cap test data

Site test result samples have been:
DnT,w+ Ctr 45dB 47dB 48dB 50dB 46dB
LnT,w 61dB 58dB 53dB 51dB 59dB

Further improvements can be made by placing 19mm gypsum based plank over the joist caps before installing the 18mm T&G chipboard.
This is highly recommended and if this is undertaken first then improved results will be in the order of:
Airborne              Impact
Rw+Ctr= 56dB    Ln,w50dB

Acoustic Joist Cap enhanced