It's a 30kg television that I'm at pains to mount properly with 10mm anchor bolts into a solid brick wall, except there is 40mm Kingspan foam insulation and finished plasterboard sandwiched between.
I'm looking for some cheap / easy to deploy (read circular) solid spacer material as I'm not keen on putting force on the plasterboard / foam combo and risking it cracking. The TV screen will be unavoidably tilted downwards a few degrees, I don't want it continuing gravity's journey.
Thought about dowel, but the grain is in the wrong direction. Metal standoff spacers from eBay are expensive.
What's cheap and ubiquitous? A hacksaw to bits from a car?
Thanks, nice products (will certainly keep it mind for other things) but looking at a datasheet Rigifix copes with a maximum gap of 20mm behind the plasterboard. I've unfortunately got 40mm of the kingspan and probably at least 15mm behind that of crumbly plaster stuff before the fixing hits pure brick. Both products are not going to grab onto much. Cheese indeed :(
That's a pint and a bag of crisps...
Have thought of that as well, but would rather avoid any stress on the plaster if I could help it.
We have to fix big tellys in hospitals, usually waiting areas. It is assumed that someone at some time will reach up to the telly and take their feet off the ground. That's the test.
When we have the sort of problem you describe we would probably:
Drill oversized holes at spacing dictated by the footplate of the wall bracket, so that we can peer and probe down them to check that the fixing hole isn't near the edge of a brick or in the mortar.
Use very long anchor bolts of a type that don't expand and risk cracking the brick. Sleeve anchors are good.
If the bricks turn out to have frogs drill to the frog then inject exterior filler then wait a few days.
You later add 15 m of plaster as well before the brick. So 15 + 40 +
12.5 + skim = 70 mm from finished face to brick, assuming no gap between kingspan and brick. How is the kingspan fixed dot 'n dab (+5 mm?) or battens (+20 or more mm = 90 mm)?
Is this a simple, just tilting, flat against wall type bracket or one with an arm so that 30 kg load could be some way from the wall bracket?
Plasterboard is pretty strong stuff in sheer. I wouldn't dismiss using hollow wall anchors into the plasterboard. I'd decide if a load spreading ply plate is desired based on the spacing of mounting bracket holes. Anything less that 30 cm square I'd fix a ply plate with 30 cm square fixings to the wall with hollow wall anchours and the bracket to that.
12 mm isn't very much for a wood screw, so either counter sunk nout abd bolt from the rear of the plate or hollow wall anchours through the lot, is ones designed for 20 to 30 mm substrate thickness are avaliable.
The plate/bracket won't fall off the PB but the PB might pull away from the wall. But the forces involved to keep a vertical wall next to a vertical wall aren't high so a few long screws (120 - 130 mm depending on the brick to finished distance) correctly sized for the plugs into a correctly sized holes 30 mm into the brick will stop that.
Most of the load puts the bracket/plate fixings into sheer with a little bit of torque, the "hold back" long screws counter that and are in tension.
Not using the PB to take the weight puts a heck of a bending moment on the fixing where it hits the wall. You either need hefty fixings,
8+ mm dia, going a fair bit into the brick 50+ mm or some means of bracing them. Some one mentioned scaff tube. Cut hole to take scaff tube *right back to the brick*, cut length of scaff tube to fit from brick to finished face, fit suitable length fixings through braket to firmly clamp scaf tube between bracket and brick, 120+ long. Note hole for scaf tube is not centered on hole for fixing. We want maximum bracing below the fixing so the fixing hole is arranged such that the fixing runs along the the top inside of the scaff tube.
Cut out hole in plasterboard larger than the TV bracket plate. Fix piece of wood direct to brick wall. Make good and paint over. Fix TV bracket to wood (or through holes in wood plate to anchor bolts in wall).
It's vertical battens, which were inter-spaced (don't ask) between slabs of kingspan when this room was decorated. The original walls were not flat, and the battens were not completely screwed flat to it. So in parts it sort off floats like a mid room partition would, hence I don't want to upset it, even screwing the tv just into the battens. The skim is painted. This is a totally wallpaper free site.
Flat against wall, not an arm.
Actually (for interest as it is amazingly strong for the price), this one.
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Only it's up high (yeah - I know), so TV will be pitched downwards.
I'll leave that for my "scared of cracks paranoia". Hate plasterboard.
Think I'm probably on the right track with the 1-inch section square steel, the four M10 anchor bolts are 140mm Fischer where the 50mm body will be located entirely into the brick. Thanks for the point of not centering fixing holes with the "tube". Will do that.
Now the above is sounding overkill?
My alternative, that Mike T has suggested, of cutting a large hole and mounting a large block of wood was my first idea, but got a lot of domestic shaking of heads around here when the 'statement of works' was discussed. Chiefly the potential mess....
Dave P suggested a toolstation pack of washers. Apart from the bending moment issue with washers, it spured a thought on getting some M12 nuts brazed together...
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