aerated block fixing/repair

[Malc]

I'm trying to fix some wall cupboards. The walls are dry lined, 12.5mm plasterboard over ~10mm air gap. The wall I reckon is aerated blocks with a skim of plaster undercoat, at least the opposite side wall was like that. I used fisher universal plugs a 10 x 3in screws. The plugs I hammered fully in with the end of the chuck to make sure they were in the block. About 2.5 of the screw is in the wall so must be 1-1.5 of the screw in the block. One cupboard has held and the screws pull tight. The others have all failed so now I need a solution to repair the failed screws. I also wonder if I've hit the mortar bed and that's why the fixing has failed.

I was thinking about some sort of resin fixing. Drill out the plug of course which would make the hole bigger too. There seems to a bit a lot of different resin tubes on screwfix. Would any be suitable? Most seem to be for fixing a stud in but I need to have a screw fixing.

Any suggestions of products that work and how to go about it?

 

[Nige F]

stud/ screw should work the same But you won`t be able to remove the screw, and you`ll need to temporary support the object being fixed until the resin is set

 

[Malc]

Not being able to remove the screw would be a problem. There is the Fischer Wet'N'Fix but how strong would that be? There doesn't seem a way of gluing in a nut/sleeve so I could use a bolt rather than a stud.

 

[mointainwalker]

You could of course just stick the Fischer plugs into the resin and screw into them when set and that would allow the screws to be removed.

Personally though, I think only 50 % in the wall and then hanging the weight a further 25 mm away from the wall is not too safe ( are these kitchen cupboards ?) and would use longer screws or even threaded bar.

 

[Malc]

The cupboards are tight to the wall, but as it is dry lined then you have 12.5mm of plaster board, say 10mm of air, 12.5mm of plaster undercoat, the cupboard back thickness, say 10mm, so 45mm of a 75mm screw, leaving 30mm in the block. Perhaps 100mm screws would be better.