Large gap between plasterboard wall and subfloor Fillers, sealants and adhesives for all types of DIY work. Help, advice and information on all aspects of this subject

[Anakarak]

I just replaced a chipboard floor and behind the skirting boards the plasterboard has a gap that is up to 4cm high and 3cm deep to the blockwork. There is also a gap of up to 15mm betwwen the flooring and the blockwork. Ideally I want to seal the gap at the bottom of the dot and dab plasterboard, the gap between floor and blockwork and the gap between the plasterboard and the chipboard subfloor, so that flanking sound can’t travel through the floor or walls. What would be the best way to fill these large gaps?

[stoneyboy]

Hi anakarak
Suggest you use expanding foam - use fire protection foam if you need fire resistance.
Regards S