50mm trunking in wall

[gm68]

Hi

I'm currently installing a TV on the lounge wall and have already chased the wall 50mm deep, unfortunately before seeing the posts here and elsewhere about maximum chase depths

What I want to know is, is there any steel reinforcing trunking/pipe available which can be installed into the chased area (in place of the brick) and plastered over, or is my only option now to brick up the chased area and start from scratch?

Thanks for any help

Gav

 

[STI]

If you are going vertical you can chase up to 1/3 of the wall thickness. If you have standard brick wall then yep 50mm is too deep but just in case you have other material wall the limit is a 1/3rd

 

[Monkeh]

Your house is not going to fall down from one vertical chase.

 

[gm68]

Yea I know (now), 1/3 vertical, 1/6 horizontal.

Just to clarify, the chase is mostly horizontal. Hence the concern.

Just wondering if I can use some structural steel tube to run the cables through and plaster it in.

For example:
http://cgi.ebay.co.uk/Steel-box-sec..._Metalworking_Supplies_ET&hash=item19bbb12d8e

or

http://cgi.ebay.co.uk/Box-section-5..._Metalworking_Supplies_ET&hash=item19b56186b8

 

[gm68]

Or

http://www.metals4u.co.uk/detail.asp?cat_id=49&prd_id=2309

 

[gm68]

May have answered my own question..... seems there are tubular steel products on the market designed for reinforcing..... 50mm x 50mm x5mm x 2.5m (square section) seems to be the best option?

Will check with vendors if this is suitable for my project, in the meantime if anyone has any advice it would be gratefully received

 

[ban-all-sheds]

Just wondering if I can use some structural steel tube to run the cables through and plaster it in.

How would you earth it?

 

[gm68]

The boxes either end are already earthed so making an earth connection to the tubing shouldn't be a problem.
Concern is primarily with structural integrity, would 5mm tubular steel be sufficient? 3mm even?

 

[ban-all-sheds]

Dunno - I'm not a structural engineer.

Intuitively 5mm would seem OK.

 

[gm68]

Me neither!
But intuitively I would also have thought that a 5mm tubular rebar should be sufficient.

 

[big-all]

surely you would need temporary support ??
you remove more than half off the brick will it start failing at any crumbly mortar joins ???

 

[gm68]

The wall has been chased to 50mm. I admit I'm a newbie and have made a mistake.
Just want to know what the way forward is....... brick it up or can I use a reinforcing bar and run the cables though it?

 

[big-all]

The wall has been chased to 50mm. I admit I'm a newbie and have made a mistake.
Just want to know what the way forward is....... brick it up or can I use a reinforcing bar and run the cables though it?

sorry missed that bit
so the answer is the wall wont nesisery fall down lol

 

[ban-all-sheds]

The answer is it hasn't fallen down yet.

I'd stick in some of that steel tube. Or 2 lengths in parallel if separation of different band cables would be useful.

 

[monday]

I am a structural engineer.....(but not an electrician)

You don't say where your lounge wall is located: outside wall, party wall, interior wall? Unless it is an interior wall it is unlikely to be only one brick thick, even the inner leaf of a cavity wall will be surprisingly strong and will redistribute load around a chase. If an interior wall it probably isn't carrying much load.

I would put some standard steel conduit in the chase, mix up some sand cement mortar (1 cement to 5 sand, add water to taste) and fill round the conduit to just below plaster level. When that has gone off (2-3 days), skim it up with plaster.

It isn't going to fall down!