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HUSH-Felt 25 meets the Building Regulation requirement for 80/140 kgs/m³ density and 25 mm nominal thickness. Tough polypropylene fibres are felted to a polyester matrix, permitting secure stapling to joist tops. The polypropylene fibres maintain their resilience over the long term, and will not fracture, perish, harden or settle more than a nominal 12%. The product is non-carcinogenic.

HUSH-Felt 25 comprises a double layer of HUSH-Felt strip, 50 mm wide, factory stapled to 140 x 50 mm hardboard slats, each having a 25 mm gap to accommodate stapling, with 16 mm staples, to joist tops. The slats present a firm, smooth surface to support the tongued and grooved short ends of the boards over the joist tops.

Chipboard, OSB or plywood tongued and grooved sheet flooring is preferred, laid across the treated joists. Traditional wood strip flooring must be glued and screwed together on intermediate timber battens. Nailing is impracticable over a resilient layer, and it is extremely difficult to achieve a satisfactory 'squeak free' floating floor in this manner. Alternatively, a hardwood veneer may be glued and pinned to a sheet floating layer. No nails or other fastenings penetrate the HUSH-Felt 25, and the floor must be permitted to float freely between walls and around door frames and pipes. A bead of water proof PVA adhesive is applied to the hardboard slats as the flooring is laid and also the tongued and grooved joints of each board (other than access panels).

Related literature

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Standard product features


Stapled to joist tops.

NBS Specification

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This product is associated with the following NBS Create clause:
45-45-70/437 Resilient layer insulation

Product specification

An important note about specifying



Hush Acoustics


+44 (0)151 933 2026

Product reference

Hush-Felt 25

Manufacturer details

44 Canal Street,
Merseyside, L20 8QU
Tel +44 (0)151 933 2026
Fax +44 (0)151 944 1146
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