Walls - What lies beneath??

D

dowlinj

Registered User
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38
Hi,

I'm fairly new to this DIY lark and last night I attempted to hang a LCD TV wall mount for a friend. Basically there were 2 sets of instructions, 1 for brick/concrete walls and one for timber/plaster board walls. The position of the holes for the screws and rawl plugs is different depending on the make-up of the wall.

Now, the instructions were straightforward enough and I was confident I could complete the task, however I wasn't quite sure what type of wall I was dealing with. It's a new apartment and the wall in question was internal, situated between the living area and one of the bedrooms. The position where the mount was to be placed was also adjacent to another wall. I knocked on it and it seemed to be hallow and I used one of those stud finder devices to try and locate the timber to which I would affix the mounting (I was now working under the assumption that I was dealing with a plasterboard/timber wall).

The detector indicated where the studs were and I marked the positions for the screws and began to drill away. Now, once I had drilled the holes, I began to realise that there was apparently no timber stud on the other side of the plasterboard. Upon closer inspection it appears that there was a thick layer of plaster/plasterboard, a gap of some sort and then some brick/concrete.

Now, I don't know the first thing about how apartments or houses are put together these days, so would someone be able to tell me how walls are "generally" constructed and what is the most probable type of wall that I'm dealing with here? I'm wondering should I have opted for the concrete/brick instructions!! Please excuse my ignorance on the subject.
 
it could be another type of wall construction where by the concrete or block built wall was covered with insulated plasterboard by 'blobbing' it on, i.e. using blobs of adhesive to stick the boards to the wall. Used for insulating the room to a higher standard than just a plastered block built wall. these boards are about 50-75 mm thick, so you may need to just get longer plugs & screws to properly attach the bracket/tv to the wall. I know that I recently attached one to a block built wall, just a couple of screws that catch a couple of holes in the back of the tv, and I was wary of how stable it was, but 2 weeks later its still hanging (would hate it to fall though).
Whatever you do, make sure they have a good grip, so you'll probably need to go right back into the block to achieve this, so you may need longer plugs and screws. And it goes witout saying to make sure you don't drill through any electrical cabling, am always paranoid about the Mrs. or one of the kids coming in to find me buzzing away and trying to grab me and therefore getting a blast themselves, which is why I told them that if they ever came across this to wallop me (or any other unfortunate individual who may be getting electrocuted) with a piece of timber.
Unfortunately, my young fellow seems to have taken that advice up a bit wrong, and seems to think that I get shocked all the time, as he keeps sneaking up on hitting me with bits of timber.
 
Thanks for that. That sounds like it could be it alright. Would explain the gap between the plasterboard and brick. Fortunately, the screws provided are heavy duty and quite long (don't ask me for specifics!!) and came with the necessary rawl plugs so I don't think they should cause any problems. They should penetrate the plasterboard and the brick work. It's a 32" TV so needs all the necessary support. I also did a 15" TV with just 2 screws like yourself, this didn't need the same level of support, more like hanging a picture. I'll make sure not to get electrocuted. Don't fancy getting battered with planks of timber!! Hanging the bracket is bad enough!
 
A 32" tv is quite a heavy object the would be in a cantilever position if you just try to use longer screws and rawlplugs to attach to the concrete wall beneath the plasterboard. You will be much better served cutting out a square of plasterboard where you will be attaching the brackets and use express nails to fix timber out to the inside of the plasterboard. Refix the plasterboard to this solid base and then attach the bracket to this. If you cut it out pretty neatly it should just slot back in and you can polyfilla/paint the joints.
 
Thanks for that but I fear that goes beyond my DIY skills, particularly as it's not my wall!! It's a good idea though. One thing, what are express nails?
 
i would not do that. its a bad idea , a lot of hassle and you would destroy the wall .
either use "rawl bolts " (best) or "hammer fixings" (next best)
to hold a telly id like at least 2 inches in the concrete wall.

rawl bolts - drill hole, push in , hang bracket, tighten nut

hammer fixings - drill hole , push in plastic bit, align bracket , push in screw bit and whack with a hammer until its tight

easy peasy
 
xt40 said:
i would not do that. its a bad idea , a lot of hassle and you would destroy the wall .
either use "rawl bolts " (best) or "hammer fixings" (next best)
to hold a telly id like at least 2 inches in the concrete wall.

rawl bolts - drill hole, push in , hang bracket, tighten nut

hammer fixings - drill hole , push in plastic bit, align bracket , push in screw bit and whack with a hammer until its tight

easy peasy
Click to expand...


problem with this idea is that you are depending on a very soft plaster board to be the anchor you tighten your rawlbolts etc against. In order for the rawlbolts/hammer fixings to expand they have to be put under pressure by tightening. You will be tightening against 12mm plasterboard with 2" air gap behind - what do you think will happen ? - my best guess would be plaster board splits and tears at back of bracket - as you say "Destroying the Wall"

And if they aren't tightened correctly - as soon as the weight is put on the bracket you will have a cantilever effect which will either -
1. pull the bolts out of the concrete. (possible)
2. push plasterboard inwards at bottom - tearing board - the effect of this will depend on what type of bracket is used to hold lcd and what the extension is on the bracket. (probable)
 
nai said:
A 32" tv is quite a heavy object................ You will be much better served cutting out a square of plasterboard where you will be attaching the brackets and use express nails to fix timber out to the inside of the plasterboard. Refix the plasterboard to this solid base and then attach the bracket to this. If you cut it out pretty neatly it should just slot back in and you can polyfilla/paint the joints.
Click to expand...

This is probably the best suggestion for drylined walls and stud partitions; regular plugs and cavity fixings are fine for non load bearing applications (like pictures, light curtains, mirrors etc) but for heavy stuff you've got to have a solid ground to fix to. In the apartments that we build we incorporate solid timber grounds at key locations (using MDF or ply) to enable fixtures to be securely hung later (including fire extinguishers, radiators, handrails, sanitary ware etc).
 
P.Ranks said:
i...
Unfortunately, my young fellow seems to have taken that advice up a bit wrong, and seems to think that I get shocked all the time, as he keeps sneaking up on hitting me with bits of timber.
Click to expand...

LOL.

Anyway with something like a 32" TV I'd be fixing my own timber to the wall aswell. I want to have a couple of heavy fixings into the concrete/block behind.
 
It's not that heavy a TV actually. Just checked the spec and it's only 11.2 kg. Would this make a difference?
 
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