Plasma wallmounting queries...

[jamieboy]

Couple of things - how deep a wallmount do you need? The picture in the TV manual shows it mounted on a stand, and says 70mm is needed behind it, but they also say that if you're wallmounting it then you should "follow the instructions that came with your bracket".

I'm guessing the 70mm has a safety margin to cover the maker, but is there an unwritten rule about how much space you actually need in reality for heat dissipation?

Second thing, and this should maybe be in DIY but I guess plenty of people here will know - what are the rules / regulations / accepted practice for running a power cable down the insulated cavity of an external wall?

Basically, I'd like to have as thin a mounting bracket as I can get away with, and I'd like to just drop the power cable down inside the wall, but if either or both of those is going to end up ruining the TV / my house, then I'll get someone who knows what they're doing to do something else instead.

[garycat]

You will probably need at least 50mm for the Scart connectors, mains plug etc unless you can get all these with a right-angle fitting.

If the speakers are on the back, as with many plasmas, mounting too close will affect the sound.

There's no problem with running a mains cable down, it should be done vertically and you can only have one spur socket off the ring main.

[jamieboy]

Thanks for that.

Sound should be fine, everything will be going through a home cinema thing.

For plugs and things, I was intending to leave a recess in the wall behind the TV for them to jut out into - something like the back-box for an electrical socket, if you can picture what I mean?

Edited by jamieboy on Thursday 17th September 18:33

[jamieboy]

I'll just give this a quick bump, with hindsight maybe it's a better fit for the DIY forum.

[Mr Will]

jamieboy said:

I'll just give this a quick bump, with hindsight maybe it's a better fit for the DIY forum.

Moved it for you!

[Plotloss]

No cables in the cavity, chase from the plaster side.

Depends on the set as to the space required, most sets have recessed input sockets and you can get flexible HDMI connectors etc.

Most flat to wall brackets (50mm) are fine in the vast majority of applications.

[jamieboy]

Plotloss said:

No cables in the cavity, chase from the plaster side.
...
Most flat to wall brackets (50mm) are fine in the vast majority of applications.

Hmmm. It's this 20mm bracket I was thinking of, because it's a) nice and slim, and b) on Der's list of suitable accessories for the TV.

The plasterboard is about 13mm, so I think I'd struggle to chase cables into that, wouldn't I? The cables must be nearly that size themselves.

I think I'm gradually answering my own "how hard can it be" question...

[headcase]

We need to know about your wall type to give advice. You mention an insulated cavity? Do you mean the cavity between the internal blockwork and exterior brickwork? So if its a new house (that have an insulated cavity) then you cant use it because its full of insulation , also if its new then the plaster side of the wall will be dot 'n' dab so you will have the thickness of the plasterboard then the gap between the plasterboard and the blockwork, sometimes this is even deep enough to post scarts through it! if it is dot 'n' dab then you will have plenty of thickness there to chase out, put capping over the cables and re plaster. The only time you get problems is in older houses that have 2 coat plaster, sometimes this isnt thick enought to take the cables so you end up chasing into the brickwork also to get the depth.

[jamieboy]

headcase said:

We need to know about your wall type to give advice. You mention an insulated cavity? Do you mean the cavity between the internal blockwork and exterior brickwork? So if its a new house (that have an insulated cavity) then you cant use it because its full of insulation , also if its new then the plaster side of the wall will be dot 'n' dab so...

It's a new-ish house, ~7 years old, timber frame.

From what I can see from taking off the existing phone / aerial sockets to have a look, it is:

13mm plasterboard : 100mm-ish cavity full of insulation : Exterior brickwork

It's not dot-n-dab, it's just (what I think of as) a normal plasterboard wall fixed to wooden studs. The cavity I'm talking about is between the plasterboard and the exterior brickwork, there is no interior blockwork.

You say "can't use it because its full of insulation" - is that can't as in mustn't use it, or as in it'll be difficult to use it? I ask because the Sky and telephone cables already come through the wall...

[miniman]

I don't see any reason why you can't run the cables between the plasterboard and the block wall behibnd, but I'm not sure you can hang a big TV straight onto a plasterboard wall even if you screw fixings right through into the block.

[cjs]

Yes you can fish the cables down the cavity, try and keep them between the plasterboard and the insulation rather than against the brick.

Obviously try and fix your bracket to the wooden studs.

Don't worry about heat, keep he screen as close as you can to the wall, it looks so much better.

[headcase]

jamieboy said:

You say "can't use it because its full of insulation" - is that can't as in mustn't use it, or as in it'll be difficult to use it? I ask because the Sky and telephone cables already come through the wall...

I was making an assumption that it was dot 'n' dab as timber frame buildings arnt too common.
You can use this space but the insulation makes fishing cables more difficult, also there will be noggins approx half way up the wall so they will cause a blockage at that point. There should be a vapour barrier directly behind the plasterboard where ever you break this you also need to fix it where possible. Chasing this type of wall is a bad idea as you end up with floppy plasterboard. Your better of making a hole behind your TV and find out EXACTLY what you have there, lots of times there is a gap between the back of the timber frame and the exterior brick work, if so then you are laughing, all you need todo is to make the hole behind your tv and carefully part the vapour barrier and the fiberglss insulation (if is kingspan then your gunna need to cut a hole through this too)and through the backer, you then do the same whereever your cables are going to come out of the wall and fish between the two. Then your gunna need to repair the lost insulation at those two points and finally tape up the vapour barrier (sometimes sprayfoam helps to re seal these areas)

If there is no gap between the timber frame and the exterior brickwork then the cables are going to have to run through the insulation layer. Its a little more tricky as the insulation gets in the way and there will be at least 1 noggin in the way, if you do come across one then all you can do is break out the plasterboard at thet point and go around the noggin and re plaster the area. Its important to repair anyware you break the vapour barrier as you can end up with damp spots that will prematurly rot out the timber frame.

[jamieboy]

Thanks for all the replies.

There's obviously more to it than I initially thought, but I reckon I'll still have a go.

Keep an eye out in a couple of weeks for my 'builder / electrician needed - urgently' thread