Insulation

How to finish off cavity and floor up to new installed bifold

Anonymous user 16/01/2026 - 7.57 AM

I recently got new bifold installed and now have a cavity between the inner & outer leaf under the bifold that I am unsure how to finish. The new bifold is sitting on the out leaf and timber joists sitting in between the bricks on the inner leaf. I want to run chipboard/plywood boards all the way up to the new bifold door before installing the finishing floor. The cavity is empty and deep. The workmen suggested no need for cavity closer when they done the work. I am unsure how to finish off the cavity up to the bifold to avoid cold bridging and any damp, should PIR be used to fully seal the cavity?. would appreciate some guidance. thanks