Running cables through a cavity

[DNS1]

Just seen someone mention on another thread that running cables in a cavity is bad practice.

Can anyone elaborate for me, I was under the impression that this was ok but not ideal in a new build etc.

How should it be done these days? I'm in a 1990s flat and just wondering how a rewire will be possible without completely trashing ALL the plasterboard!

 

[Mark_Burgess]

sorry to change subject alittle but,as u say lenny bridging moisture gap, how does that relate to the pump in type cavity wall insulation. had mine done 2yrs ago now seem to have a lot of damp. any advice anyone?

Some of the older insulation was of a porous type so that when the driving rain soaked through the outer wall it wicked through to the inner wall causing damp. The new stuff is supposed to be a silicone based product, I don't believe and will never get this pump in stuff done.
A mate of mine how is a builder, has partially pulled down a pumped insulated wall in prep for an extension, the black mould damp was unbelievable.
I truly believe in insulation whilst a new build as an air space cavity still remains.

Back to running tails through the cavity, I usually use a but of 40mm waste pipe, that can be sealed into place and a little bit of intumescent pillow in the pipe sorts the fire barrier.

 

[Richard]

If were talking about meter tails here, then sorry but it's stright through the cavity for me every time!! I'm aware it's probibly against building regs, but until I see problems with it for myself, i'm carrying on like that!

 

[SPARTYKUS]

Is the capping really necessary?

I've always been under the impression that for a new build the cables are normally just clipped direct to the breeze block before the dot and dabbing...

capping is to stop the plasterers trowel, and thats it! Thats why you get plastic capping! So if it's being dot & dabbed then it is not necessary and a waste of time. But nowt to stop you doing it and making it look really pretty .....

 

[Rampage]

Could you use flexible conduit threaded through from say the CCU downstairs to upstairs through the cavity?

Have to admit I ran a bathroom fan through a cavity today!

 

[GT1]

Slightly off-topic I know. But kind of on the same subject.
It hasn't happened yet but I'm sure sometime soon I'll have to 4" core drill through a wall with blown in insulation for a kitchen extractor.!
What happens to the insulation ?

 

[UNG]

Do people not get taught this in apprenticeships?????

What apprenticeships, didn't they cease to exist years ago to be replaced with the quick course

Slightly off-topic I know. But kind of on the same subject.
It hasn't happened yet but I'm sure sometime soon I'll have to 4" core drill through a wall with blown in insulation for a kitchen extractor.!
What happens to the insulation ?

Depends on the insulation used, blown wool usually stays in place to some degree long enough to get a sleeve in the worst stuff I have found is the polystyrene chips I usually drill some small holes around the diameter of the core bit and inject some foam before using the core drill, the foam will retain the poly chips in the wall and cut down the mess

 

[GT1]

Ahhhh.
Excellent idea !