Routing speaker cables through thermally insulated plasterboard

[pcdj]

Sorry if this is in the wrong section. Please can an admin move this post if so.

I'm having a dilemma on how to route some speaker cables through, or behind, the plasterboard in my living room.

The plasterboard appears to be of the thermally insulated type - 14mm of plasterboard plus another 25mm or so of polystyrene, directly attached to the breezeblock of an external wall.

The previous occupants have left us with a vertical conduit in which to run power/HDMI/coax cables vertically up the wall behind the TV but I'd like to extend two runs of speaker cable to the left and right of the TV horizontally where some surround speakers will be mounted on the wall.

I've poked a long coat hanger in through one of the conduit access panels to check if there's any clearance between the polystyrene and breeze block and can't seem to get very far at all, so fishing the speaker cable through that void is a no-go.

Does anyone have any recommendations on how best to achieve this?

 

[ktuludays]

You're going to have to make a hole to do what you want then make good afterwards

 

[pcdj]

You're going to have to make a hole to do what you want then make good afterwards

Sorry, I'm not following. A hole to where?

If I cut through the plasterboard I hit the thermal insulation; if I cut through that I hit breeze block; beyond that is the exterior of the house. All three layers have no gaps in between.

 

[Tigercubrider]

 

[pcdj]

That's really cool!

Unfortunately I have to go horizontally sideways from my TV, rather than vertically :-/

 

[Tigercubrider]

There must be timber between sheets of PB?
If there wasn't then possibly a reasonable sized hole behind the TV and a length of blue water pipe could be rammmed sideways, withdrawn and tried again, possibly using a vacuum cleaner to suck debris out?
Or drain rods/ copper pipe ?

 

[Tigercubrider]

Is there any gap between the PB /polystyrene /breezeblock?
There is a system that uses magnets to pull a string through rockwool type insulation.

You could try pulling fishing wire through with cobalt magnets off eBay or £25 for the proper tool - but it won't tunnel through solid polystyrene

I guess you could create a tool with a bendy pipe and a battery with a paper clip as a Hotwire? Don't blame me if the house burns down

 

[geraldthehamster]

That hot ball is going to work on polystyrene, but I don't see it working on PU-backed insulated plasterboard.

The OP is going to have to make a channel, as suggested, then make good afterwards.