Our ~1990s built home has ~25 mm thick EPS foam boards in the cavity between outer brick and inner block. Based on a couple of borescope images (unfortunately I don't have a copy of these), it doesn't look particularly well secured, or evenly distributed.

 

Is there any established method to break up these foam boards, ready for removal by vacuum? This would then leave the cavity ready to be refilled in a more complete / consistent way via pumped EPS beads. 

 

I'm trying to work out if it's worth investing more into improving the cavity insulation, or to focus solely on internal wall insulation (or maybe a combination of both). 

 

Sharing a photo as an example (not the actual external cavity wall, but an internal block / block wall with similar insulation between).

 

I realise this is a very similar ask to @HughF's recent thread, but wanted to ask specifically about removal of EPS foam boards.

 

Apparently the eps beads are very free flowing, so I’d assume that the application technician would be able to inject all around the foam boards?