AV cables in solid wall - what the regs say?

[Deuce]

Hi all,

Just being cheeky and asking for some advice really..

In my new house, we have solid walls throughout - great, but not so great for my home cinema kit. My issue is that whilst I would can chase the AV cables to wherever they need to be, I would prefer to do it in such a way that leaves the system open for future expansion. In the previous house we had stud walls and I was able to route flexible trunking between wall ports and pull through/swap whatever I needed.

In an ideal world, I would do something similar by cutting into the block, embedding some solid wall PVC trunking/pipe, and plastering back over. I can keep all my cuts continuous in either the horizontal or vertical, but my concern is what depth I'm allowed to cut into the block wall. Ideally I would need to go in to the block in 50x50mm channels to allow the space to run multiple feeds including moulded connectors... I'm not as regs savvy as you lot so thought I'd just ask the experts

NB for the mains power I'm chasing along separate routes to run the mains independently from speaker flex/hdmi etc.

 

[snowhead]

When you say solid I assume you mean Block / Cavity / Brick as opposed to Timber frame / Cavity / Brick?

Cutting 50mm depth into 100m blocks isn't going to do much for thier structural strength.
How long are these 50m chases going to be?

 

[SparkyChick]

So the EGBR (Electricians guide to the building regulations) sets out maximum permissible chase depths....

Horizontally across the wall it's one sixth of the wall/leaf thickness
Vertically up and down the wall it's one third of the wall/leaf thickness

And the handy diagram on page 144 of the 17th Amd 3 edition appears to include the finish in this. For 20mm OD, you'd struggle going horizontally with a leaf thickness of 100mm but vertically, no problem.

 

[Deuce]

When you say solid I assume you mean Block / Cavity / Brick as opposed to Timber frame / Cavity / Brick?

Cutting 50mm depth into 100m blocks isn't going to do much for thier structural strength.
How long are these 50m chases going to be?

Yes, block, cavity, brick.

I could use something like 50 x 25mm trunking to limit the cut depth. I am concerned about the amount of block I would be removing (I assume there is a building regulation that covers that!?). Obviously 50 x 50mm trunking would be preferable if it was allowable, but I can cope with 50 x 25mm..

Length wise, probably a horizontal length of 2m for the main run, with an inspection cover at either end. Then a vertical drop down another metre or so from each end (so in the end, the cuts form a goal post shape).

 

[suffolkspark]

Use a bit of D-line trunking

 

[Deuce]

So the EGBR (Electricians guide to the building regulations) sets out maximum permissible chase depths....

Horizontally across the wall it's one sixth of the wall/leaf thickness
Vertically up and down the wall it's one third of the wall/leaf thickness

And the handy diagram on page 144 of the 17th Amd 3 edition appears to include the finish in this. For 20mm OD, you'd struggle going horizontally with a leaf thickness of 100mm but vertically, no problem.

Useful and informative, but annoying!

How do people deal with AV in solid walls then? at 1/6th leaf thickness there is no chance of embedding trunking sufficient to pull through HDMI or anything else with moulded connectors really, and I can't just do vertical runs due to the fireplace - I have to go up and across at some point. I know that runs should be straight, so I was going to install inspection points at the corners with flush fitting covers to make it obvious where the run started/ended at.

My other option is to go through the cavity wall and do it all on the exterior...

 

[Deuce]

Use a bit of D-line trunking

What... on the wall surface

The last thing Mrs Deuce will accept is anything on the wall, it was hard enough to convince her that surround sound is 'vital' in the first place..

 

[suffolkspark]

Is the fireplace used? If not you could drill at an angle to cone out in the corner of the room beside it then trubk top to bottom down the corner

 

[telectrix]

Kopex into and up the cavity.

 

[littlespark]

Stud the wall, new plasterboard and form a cavity.
Yes, much work and lose 2 inches off length of room, but it wouldn’t look like you’ve cut a huge dusty channel in your wall and patched it up.

 

[Deuce]

Kopex into and up the cavity.

Are there not regs about running cables (albeit not mains in this instance) through the cavity?

 

[Deuce]

Is the fireplace used? If not you could drill at an angle to cone out in the corner of the room beside it then trubk top to bottom down the corner

It will be used, there is a log burner going in at the same time, ahead of then plastering/decorating once all done.

 

[SparkyChick]

I'm surprised none of the guys have suggested this to be honest... New Mrs. Deuce... one who understands the value of surround sound and AV and who doesn't mind a bit of trunking if it helps achieve the end result


Just kidding of course

 

[Deuce]

Stud the wall, new plasterboard and form a cavity.
Yes, much work and lose 2 inches off length of room, but it wouldn’t look like you’ve cut a huge dusty channel in your wall and patched it up.

Sadly the fireplace prevents this - the fireplace itself would have to be brought forwards by the same distance. Possible but costly!

 

[Deuce]

I'm surprised none of the guys have suggested this to be honest... New Mrs. Deuce... one who understands the value of surround sound and AV and who doesn't mind a bit of trunking if it helps achieve the end result


Just kidding of course

I've been looking, but in spite of my rugged good looks and disease free status, there have been fewer takers than I had hoped.

But thank you for the offer, it's always good to have backup options

 

[Squid]

How serious are you about you AV stuff as it might be cheaper to sell the house and build your own?

 

[Deuce]

How serious are you about you AV stuff as it might be cheaper to sell the house and build your own?

View attachment 45997

Wow that's some setup - I don't even know what the things in a circle on the floor are!?

Mrs Deuce would not accept anything like that. She's a hard, angry woman

In the next house I'm totally having a dedicated cinema room though

 

[suffolkspark]

how about going straight up central from behind the tv..... then under the floor boards and 1 straight run down in a corner? just put spare hdmi cables in... presuming the wall is this shape>? ---|__|---

p

 

[Squid]

Wow that's some setup - I don't even know what the things in a circle on the floor are!?

Mrs Deuce would not accept anything like that. She's a hard, angry woman

In the next house I'm totally having a dedicated cinema room though

That set-up cost $6M

Mate has a cinema room, 5M screen sofa's etc etc full cinema surround sound etc etc I think he has 225 speakers around the house, the sound is amazing in the cinema room though.

 

[Deuce]

That set-up cost $6M

Mate has a cinema room, 5M screen sofa's etc etc full cinema surround sound etc etc I think he has 225 speakers around the house, the sound is amazing in the cinema room though.

225 speakers

I'm not quite at that level! I just have a 5.1 setup (although very high quality), but want to leave scope to add another two speakers to have a 7.1 setup.

My AV receiver does also have the capability to control speakers in other rooms too, which I'll probably allow for during this install. Not that I can afford speakers for any other room just yet, the new main stereo speakers in the lounge are going to be around £2k second hand..

Makes a hell of a difference when you're watching movies though. surround sound is certainly not just a gimmick