Hanging a heavy mirror on block backed plasterboard

[aex57]

I bought some self drilling screws such as these today to provide two screws to hang a fairly heavy mirror onto a plasterboard wall (roughly 10mm thick). I have used this approach previously for a heavy bathroom cabinet into plasterboard with good results. This time I started to turn the self drilling screws into the plasterboard and once through immediately hit a concrete type block which prevent my screw going all the wall.

I guess my only option now is a long screw through the plasterboard and into the block but I do not know how to gauge the length of the screw I need, what type of screw I should use, nor what plug is most suitable. Do I need a really long plug to accommodate the really long screw?

Thanks in advance.

 

[SFK]

If you are happy with those fittings taking the load of the mirror....
If the gap between the plasterboard and wall is small I have cut the blade section off the fitting to make it shorter.
(have to then use a drill to make a pilot hole).

Sfk

 

[foxhole]

70mm screw into standard wall plug will do, plug does not bed to be long just make sure all of it is in the block.No good cutting down the current plugs as screw will still be too long .

 

[aex57]

If you are happy with those fittings taking the load of the mirror....
If the gap between the plasterboard and wall is small I have cut the blade section off the fitting to make it shorter.
(have to then use a drill to make a pilot hole).
Sfk

Thanks for the comment, I'm confident the fittings will take the weight and had considered chopping the end off to shorten it, but as Foxhole points out the screw supplied with the fitting would still be too long.

70mm screw into standard wall plug will do, plug does not bed to be long just make sure all of it is in the block.No good cutting down the current plugs as screw will still be too long .

Do you think the plug and screw being in the block would give good strength and hold up a heavy mirror? I guess this would be stronger than the fitting into plasterboard I am suggesting. Regarding the plug, if it is just to go into the block only, I suppose I'll have to drill a hole in the plasterboard larger than in the block so I can push the plug through and into the block. This job was supposed to be an easy one - sigh.

Thanks all.

 

[SFK]

Foxhole suggestion is better (stronger) than mine.

But answering your question,

screw supplied with the fitting would still be too long

I would drill a 4mm wide hole in wall to take the end of the screw.

 

[aex57]

Foxhole suggestion is better (stronger) than mine.

But answering your question,

I would drill a 4mm wide hole in wall to take the end of the screw.

I would definitely consider this as an option. The problem now is that the plasterboard at the location I want to fix to is now ruined so I think this option is off the table. Unless I move the positioning of the mirror a bit lower and get a fresh attempt. I'm sure I've weakened that general area of the plasterboard now even if I fill the hole in.

 

[foxhole]

I would definitely consider this as an option. The problem now is that the plasterboard at the location I want to fix to is now ruined so I think this option is off the table. Unless I move the positioning of the mirror a bit lower and get a fresh attempt. I'm sure I've weakened that general area of the plasterboard now even if I fill the hole in.

Doesn’t matter about the plasterboard the screw will be fixed in blockwork, the hole you have will allow plug to be inserted .