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How to soundproof an existing floor where the ceiling is replaced

How to soundproof an existing floor where the ceiling is replaced

Q: How do I soundproof an existing floor where the ceiling is replaced?

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A: Soundproofing an existing floor in a refurbishment or conversion development is simple with one of Cellecta’s soundproofing acoustic floor board treatments. If the ceiling below is being replaced we offer DECKfon 37T a high performance tongue and groove board with a high performance resilient layer. To install the system following the installation process below.

DECKfon 37T sound proof flooring

Preparation[dt_divider style=”thin” /]

Before commencing installation of the acoustic flooring system, ensure the building is weather tight. The timber joists should level, securely fixed and swept clean of any building debris to allow the DECKfon CHiP 37T boards to be laid flat. All potential air paths in the surrounding walls should be sealed with materials.

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1. Place YELOfon FS (Flanking Strip) around the floor perimeter.

2. Lay the DECKfon boards in a staggered formation across the floor. Apply Cellecta “fon” PVA adhesive to all joints, ensuring the boards are fitted together tightly.

3. Install wall skirting and trim off excess FS strip.[dt_call_to_action style=”1″ background=”plain” content_size=”normal” text_align=”left” animation=”none” line=”true”]NOTES.

To address possible flanking transmission – DECKfon boards must not make direct contact with the wall or its treatments.  To prevent this place YELOfon ES (Flanking strips) around the floor perimeter.

NO mechanical fixing should be used to fix DECKfon boards.  Apply Cellecta fon” PVA adhesive to the t&g edges and push tightly together. Wipe off any excess adhesive with a damp cloth.   [/dt_call_to_action]


Ceiling boards should be installed prior to the wall treatments to prevent flanking transmission, especially when “dot & dab” is adopted. Two layers of plasterboards with a minimum mass of 20kg/m3 should be fixed to resilient bars in accordance with the manufacturer’s recommendations, perpendicular to the floor joists.

Floor Cavity Insulation

To achieve acoustic efficiency, 100mm 45kg/m3 mineral wool insulation should be placed into the void between the joists, on top of the ceiling. There must be no any gaps between the insulation and the surrounding structures.


Stud partitions should be built directly off the timber floor joists to reduce the effect of camber. A flanking strip should then be installed to eliminate acoustic flanking.


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Kitchen units can be built off the DECKfon 37T boards. Seal any gaps around services with flexible mastic.

Bathrooms and Washrooms 

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When laying DECKfon boards in a bathroom it is recommended that the bath is fixed to a sub-floor and the DECKfon boards are dressed up as close as possible to the legs of the bath (without touching them). The bath surround can then be installed, thus producing a flush, neat finish. Seal any gaps with flexible mastic.

Mount all sanitary ware on timber packing built off a timber sub-floor (to the same height as DECKfon) and dress the DECKfon boards to within 5mm and seal all gaps with flexible mastic.


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Boards should be stored level in a dry environment. The foam on DECKfon boards is manufactured from polyurethane polymers and should be kept away from naked flames and smoking near the boards should be prohibited.


DECKfon boards are heavy. Care should be taken when lifting them. Appropriate gloves should be worn to protect hands from splinters.


When cutting the board either by hand or machine, a dust mask should be worn as the dust particles may irritate if inhaled.


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Should you need any further assistance in installing DECKfon boards or specific information regarding your soundproofing project, please do not hesitate to contact our technical team on 08456 717174 or email technical@cellecta.co.uk.

Posted in: Acoustic Insulation

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